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Poster Summaries

Effects of Oxidant Air Pollutants on Pine Litter-fall and the Forest Floor 2

Rodney J. Arkley and Rudolph Glauser

Oxidant i n j u r y t o western yellow p ines (Pinus ponderosa and P. Jeffrey!) i n t h e San Bernardino Mountains r e s u l t s i n need le i n j u r y followed by inc reased f a s c i c l e m o r t a l i t y and a b s c i s s i o n , decreased needle l e n g t h , branch m o r t a l i t y and f i n a l l y t r e e m o r t a l i t y . The degree of i n j u r y has been es t ima ted each year f o r 6 yea r s by a scor ing system based on obse rva t ion of a l l of these f a c t o r s w i t h b inocu la r s and combining them i n t o a s i n g l e oxidant i n j u r y s c o r e (01s). Fol iage d e n s i t y i s d i r e c t l y p r o p o r t i o n a l t o OIS a s expected. The number of annual needle-whorls r e t a i n e d (W) i s r e l a t e d t o t h e s c o r e by W = 0.171 x OIS wi th r = .75** and t h e grams of need les pe r twig by F = 2.71 x OIS wi th r = .62*. Note t h a t OIS dec reases w i t h i n c r e a s i n g i n j u r y and a score of 0 i n d i c a t e s a dead t r e e . Scores g r e a t e r than 35 i n d i c a t e no obvious i n j u r y .

EFFECT ON NEEDLE-FALL The oven-dry weight of need les c o l l e c t e d on

0.209 m2 s c r e e n s placed under p i n e s of varying OIS is shown i n Figure 1. The average annual need le f a l l i n c r e a s e s from 131 gm/m2 under h e a l t h y t r e e s t o 357 gm/m2 wi th OIS of 9 t o 14, and dec reases a s t h e t r e e n e a r s dea th ,

The weight pe r need le f a s c i c l e i n t h e l i t t e r - f a l l dec reases p rogress ive ly wi th i n c r e a s i n g i n j u r y a s shown a l s o i n Figure 1. (Sig. < .001).

The inc reased l i t t e r - f a l l (170 pe rcen t ) can be expected t o i n c r e a s e t h e t h i c k n e s s of loose d ry l i t t e r on t h e f o r e s t f l o o r wi th consequent inc reased f i r e hazard and decreased seed l ing germination.

P l a n t Nut r i en t Content L i t t e r - f a l l samples were analyzed t o determine

t h e e f f e c t of oxidant i n j u r y on t h e p l a n t n u t r i e n t of t h e l i t t e r . The r e s u l t s a r e shown i n Figure 2. The s c a t t e r of p o i n t s (not shown) represented by t h e r e g r e s s i o n l i n e s is wide, bu t 187 samples were analyzed and t h e t r e n d s ind ica ted a r e c l e a r l y r e a l , s i n c e they a r e h i g h l y s i g n i f i c a n t (P = < .001). Magnesium was a l s o analyzed b u t

p r e s e n t a t t h e Symposium on E f f e c t s of Ai r P o l l u t a n t s on Mediterranean and Temperate Fores t Ecosystems, June 22-27, 1980, R ive r s ide , C a l i f o r n i a , U.S.A.

2 ~ o i lMorphologist and S t a f f Research Associa te , r e s p e c t i v e l y , Dept. of S o i l s and P l a n t N u t r i t i o n , Unive r s i ty of C a l i f o r n i a , Berkeley, C a l i f .

showed no t r end whatsoever. The response of t h e s e elements i s perhaps due

t o d e c l i n i n g c e l l w a l l th i ckness wi th i t s calcium p e c t a t e and an i n v e r s e d i l u t i o n e f f e c t on N, P, and K.

The d a t a f o r t h e r e g r e s s i o n l i n e s shown i n Figure 2 a r e a s fo l lows:

N(pct) - ,598 - .00255 QIS, r = -.264, n = 187 P(pc t ) = .0707 - .00034 OIS, r = -.28, n = 185 K(pct) = .346 - .00331 OIS, r = -.37, n = 187

Ca(pct) = .303 + .00431 OIS, r = .58, n = 147

0 MEAN 1

"I - RANGE n

I 0* \- 5 NI

/ -\+I \ - .2S'Si

Â

1 I ' Â-./ b - .20 2

Ã1 NEEDLE SIZE - .IS ZI

Oxidont Injury Score Dead 4 Heolthy

Fig. 1. E f f e c t of oxidant i n j u r y on p ine need le f a l l and need le s i z e .

3 I 1 I I 1 1z 01 10 20 3 0 40 50

Oxidant Injury Score Dead < Healthy

Fig. 2. Needle-fall con ten t of p l a n t n u t r i e n t s .

Regional Air Pollution Impacts on Forest Growth

Thomas V. Armentano, Orie L. Loucks, and Wayne T. wi l l iams2

Recent s t u d i e s underway i n t h e Ohio River Basin Energy Study (Loucks 1980) have shown t h a t chronic a i r p o l l u t i o n l e v e l s may b e reducing r e g i o n a l growth over much of e a s t e r n North America. During June through August, 1977, monitoring s t a t i o n s r e p r e s e n t a t i v e of f o r e s t a r e a s recorded hour ly maxima > 0.10 ppm on 14 t o 27 percent of t h e days, and maxima > 0.05 ppm on 70 t o 93 percent of t h e days.

A survey of e a s t e r n whi te p ine (Pinus s t r o b u s L.) s t a n d s i n r u r a l and urban l o c a t i o n s throughout c e n t r a l and sou the rn Indiana showed widespread ozone damage symptoms: c h l o r o t i c mot t l ing , c h l o r o t i c dwarfing and premature need le senescence, on a s c a l e from moderate t o severe . Sycamore (Plantanus o c c i d e n t a l i s L . ) , s i l v e r m a p l e (& saccharinum L . ) , yellow poplar (Lireodendron t u l i p i f e r a L. ) , and t h e black oak group (Quercus spp. ) a l s o a r e somewhat s e n s i t i v e . The 37.3 x l o 6 a c r e s of f o r e s t s i n t h e Ohio Basin y i e l d about 40 f t 3 / a c r e 1 of wood an-n u a l l y , bu t an es t ima ted 25 pe rcen t of t h e f o r e s t c o n s i s t s of 03-sens i t ive s p e c i e s , i n d i c a t i n g a y i e l d r educ t ion from oxidant e f f e c t s (and i n t e r a c - t i o n s w i t h o t h e r gases and pathogens), ranging from 3 t o 6 pe rcen t annual ly (Table 1 ) .

Table I--Total l o s s i n wood product ion i n Ohio River Basin f o r e s t s e s t ima ted t o r e s u l t from d i r e c t and i n d i r e c t a i r p o l l u t a n t e f f e c t s upon f o r e s t growth and m o r t a l i t y r a t e s . To ta l normal wood y i e l d f o r t h e r eg ion i n 1970 was 1 . 5 x 10' f t 3 . Data expressed i n m i l l i o n s of cub ic f e e t .

Wood Annual Product ion M o r t a l i t y

Loss 1 Loss T o t a l Loss 1(pe t . ) 1 ( lobf t3 ) I ( P C ~ . )( 1 0 b f t 3 ) (pe t . )

Independent s t u d i e s i n d i c a t e 03 l e v e l s w i l l in-c r e a s e i n t h e Ohio River Basin over t h e next 20 y e a r s , depending on i n c r e a s e s i n u t i l i t y NOx emis-s i o n s . A conse rva t ive energy development scenar io

'presented a t t h e Symposium on E f f e c t s of Air P o l l u t a n t s on Mediterranean and Temperate Fores t Ecosystems, June 22-27, 1980, R ive r s ide , C a l i f o r n i a , U.S.A.

r e s e a r c h S c i e n t i s t , Science D i r e c t o r , and Research S c i e n t i s t , r e s p e c t i v e l y , The I n s t i t u t e of Ecology (TIE), Ind ianapo l i s , Indiana.

suggests t h a t O 3 l e v e l s w i l l cont inue upward a t l e a s t through 1985. A t t h e c u r r e n t r a t e of 03 in - c rease , 0.02 ppm per decade, wood l o s s e s could reach 166 x l o 6 f t 3 , twice t h e c u r r e n t es t imated l o s s e s (Table 1 ) .

A p a t t e r n of inc reas ing t r e e m o r t a l i t y i n t h e r e l a t i v e l y young e a s t e r n f o r e s t s (30 percent mor-t a l i t y inc rease i n t h e Northeas t , and 10 pe rcen t i n t h e South from 1962 t o 1970) has been repor ted dur ing a per iod of s i g n i f i c a n t a i r p o l l u t i o n in-c reases i n t h e Northeas t (U.S. Fores t Se rv ice 1978). This m o r t a l i t y may be a t t r i b u t a b l e , a t l e a s t i n p a r t , t o degradat ion of a i r q u a l i t y . This hypothesis i s supported by n e a r l y cons tan t m o r t a l i t y i n western f o r e s t s where a i r p o l l u t i o n i s g e n e r a l l y low, d e s p i t e overmatur i ty i n these f o r e s t s . I f mor-t a l i t y l o s s e s i n t h e Ohio Basin were in te rmedia te between those of t h e Northeast and South from 1962 t o 1970, t h e l o s s of wood would be 4.08 f t 3 / a c r e / y r l . Propor t iona te ly g r e a t e r l o s s e s a r e i n d i c a t e d f o r 1985 and 2000 (Table 1 ) .

Other s t u d i e s underway i n d i c a t e t h e s e f o r e s t l o s s e s could be s i g n i f i c a n t f o r t h e g l o b a l C02 balance (Armentano and Rals ton 1980). Because of a f avorab le s t a n d age d i s t r i b u t i o n brought on by p a s t ha rves t p a t t e r n s , temperate zone f o r e s t s now s t o r e around 10' tons of carbon annual ly i n long- l i v e d t r e e components, 20 percent a s much a s t h e carbon r e l e a s e d from f o s s i l - f u e l combustion. This s t o r a g e could cont inue f o r t h e next two decades, bu t increased h a r v e s t , f o r e s t maturat ion, and a i r pol lu- t i o n e f f e c t s can reduce carbon seques te r ing and wood product ion r a t e s . Thus, only management of f o r e s t s focused on a balance between wood product ion and wood accumulation can provide optimum economic and eco log ica l b e n e f i t s . I f p resen t a i r p o l l u t i o n t r ends cont inue, and i f r e l a t i o n s h i p s t o f o r e s t growth suggested i n t h i s paper a r e s u b s t a n t i a t e d by f u r t h e r r e sea rch , t h e long-term p r o d u c t i v i t y of f o r -e s t s w i l l be th rea tened i n s e v e r a l r eg ions of t h e United S t a t e s .

LITERATURE CITED

Armentano, T.V. , and C.W. Rals ton. 1980. The r o l e of temperate zone f o r e s t s i n t h e g loba l carbon cycle . Can. J. For. Res. 10:53-60.

Loucks, O.L. (ed.) . 1980. Crop and Fores t Losses Due t o Current and Pro jec ted Emissions from Coal- f i red Power P l a n t s i n t h e Ohio River Basin. TIE Report i n review. Ind ianapo l i s .

U.S. Fores t Service . 1978. Fores t S t a t i s t i c s of t h e U.S. 1977. De-partment of Agricul ture .

Canopy Analysis of Pollutant Injured Ponderosa Pine in the San Bernardino National Forest l 3

M.C. Axelrod, P.I. Coyne, G.E. Bingham, J.R. Kercher, P.R. Miller, and R.C. ~ u n ~ ~

Nine trees were selected from a ponderosa pine (Pinus ponderosa Laws.! stand which was estab- lished after a fire in the mid-1950's. These trees were classified into three injury groups, [(I) slight, (2) moderate, and (3) severe injury] in accordance with a scoring devised by P.R. Miller. During the summers of 1978 and 1979, a detailed inventory was made of the canopy on each tree. The lengths of all main stem internodes

.were measured along with the number of primary branches radiating from each of these internodes. At roughly every other main stem internode, sev-eral of the primary branches received a detailed inventory. The length of the primary branch and the number of internodes were recorded. This inventory was carried on through to the secondary, tertiary, and quarternary branch levels. The compass angle of each of the inventoried primary branches was also recorded. Whenever needles were found on an internode, the following information was recorded: (1) needle age, (2) needle condition on a scale of 0-4, (3) the number of fascicles, (4) the average needle length, (5) the average needle chord width, and (6) the length of the internode bearing the needles. Note that while not all the primary branches at a selected main stem internode were inventoried, the ones selected did receive a complete inventory.

A preliminary analysis of the 1978 canopy data has been completed, characterizing the distribution of needle surface area for each tree. The total needle surface area for each inventoried primary branch was computed separately for each needle age. In order to determine the distribution of needle surface area for a whole tree, we estimated the needle area at the main stem internodes where no data was taken. The curve repre- senting needle area as a function of height is approximately bell-shaped. We have developed an algorithm designed to yield estimates of the missing points and a smooth curve. The algorithm is iterative and uses linear interpolation be-

presented at the Symposium on Effects of Air Pollutants on Mediterranean and Temperate Forest Ecosystems, June 22-27, 1980, Riverside, California, U.S.A.

~lectrical Engineer, Lawrence Livermore Natl. Laboratory (LLNL), Livermore, Calif.; Plant Phys- iologist, Southern Plains Range Research Station, uSDA/SEA/AR, Woodward, Okla.; Environmental Scien- tists, LLNL; Research Plant Pathologist, Pacific Southwest For. and Range Exp. Stn., Riverside, Calif.; and Environmental Scientist, LLNL.

work performed under the auspices of the U.S. Department of Energy by the Lawrence Livermore Natl. Laboratory under contract number W-7405- ENG- 48.

tween known points to produce a set of initial estimates. The algorithm first computes the cumulative needle surface area as a function of height, then a linearizing transformation is made. Linear interpolation is carried out on this new curve. The transformation is then inverted and first differences taken, resulting in a reproduc- tion of the original data and a new set of estimates for the missing data. The new estimates are used as initial values each iteration. A weighted average of the needle conditions for each primary branch was also computed. These averages are then combined to yield an index of the condition of the needles on the whole tree.

In table 1A, we see the total leaf area index for each needle age class, with the trees grouped into injury classifications. We can see the leaf area indices decrease across injury classes within age groups. There is a pronounced decrease in the retained leaf area with needle age even in the slightly injured group; the severely injured group has essentially no needle area except in the 1 year age category. Table 1B shows the (weighted) average needle condition for the inventoried trees and presents further evidence that ozone injury is dose accumulative with young needles being less affected by ozone than older needles. Since the current year needles were still growing at the time the initial inventory was taken, they were inventoried separately the following year. This data is still being processed and is not yet available, but is expected to add proportionately to the numbers presented here. The trend in leaf area decline indicates the competitive disadvan- tage of an injured tree.

Table I--Needle properties by needle age for nine trees under pollution stress. -

(A) Leaf Area Index Injury Class 1 Year 2 Year 3 Year

Slight 9.53 4.13 0.70 Moderate 5.23 0.73 0.00 Severe 3.55 0.03 0.00

(B) Average Needle condition2 of Canopy

Slight 0.96 1.31 1.28 Moderate 2.18 2.42 NA Severe 2.63 NA NA

"~oes not include data for current year needles. Averages for 3 trees in each injury class.

~ e e d l e condition scale: 0 = green; 2 = chlorotic mottle. 4 = uniform yellow with necrosis.

Photosynthesis and Stomatal Behavior in Ponderosa Pine Subjected to Oxidant Stress: Water Stress Response 1 1 2

Gail E. Bingham and Patrick I. coyne3

Light response curves for net and/or gross photosynthesis, stomatal conductance, and needle xylem potential of ponderosa pine (Pinus ponderosa Laws.) subjected to water and/or ozone stress were studied in the field and laboratory. In the field, measurements were made on a stand of ponderosa pine in the San Bernardino National Forest, which has experienced long-term oxidant fumigations from the south coast air basin since their establishment following fire in the mid-1950's. These trees were stratified for comparative studies into three groups (slight injury, moderate injury, and severe injury) having similar oxidant symptoms, on the basis of the scoring system of P.R. Miller.

Controlled studies using ten healthy, uniform, Oregon-grown, six-year-old saplings growing in 55 1 containers were conducted to elucidate specific field responses. These trees were approximately 2 m tall, and were randomly allocated to positions in two naturally-lighted, mylar- covered, air and humidity conditioned exposure chambers. One chamber was supplied charcoal filtered air and the other with air containing 0.01 ppm ozone for six hours/day during the midday period.

Measurements were made at regular intervals from May through October at the forest site and during the fumigation and water stress cycles in the laboratory. During the laboratory study, net photosynthesis (Pn) and stomatal conductance (Cs) measurements were made at constant humidity and temperature using the LLNL developed minicuvette system, with only the fascicle being measured and a few surrounding needles exposed to light. The rest of the tree was surrounded with heavy black cloth from before dawn until after light response curves had been measured on three fascicles.

The relationship between needle xylem potential and maximum stomatal conductance (Cmax) was not single valued, and depended on predawn

"presented at the Symposium on Effects of Air Pollutants on Mediterranean and Temperate Forest Ecosystems, June 22-27, 1980, Riverside, California, U.S.A.

'work performed under the auspices of the U. S. Dept. of Energy by the Lawrence Livennore National Laboratory under contract number W-7405-ENG-48.

3~nvironmental Scientist , Lawrence Livermore National Laboratory, Livermore, Calif.; Plant Physiologist, Southern Plains Range Research Station, USDA/SEA/AR, Woodward, Okla.

qX. When predawn ifiv was in the range from -3 to -5 bars, Cs (and Pn) decreased only slightly during the normal daily decrease in ifiv due to changes in the diurnal course of irradiance. Minimum iy under these conditions seldom exceeded -14 bars. However, when $x was forced below -15 to -17 bars (by severing the fascicle from the branch) a sharp decrease in Cs occurred, with complete stomatal closure (Cs<O.O1 cm/s) in the range of -36 to -40 bars. When predawn started in the -5 to -8 bar range, however, a bilevel relationship between Cg and iy was observed, with Cmax reaching an initial full light value, followed at some later time by a step decrease to a lower value. Conductance and Pn remained at this significantly lower level throughout most of the day, with an accelerated closing trend toward the late afternoon. Late afternoon values were usually only 60 to 70 percent of their light corrected morning opening value.

Care had to be taken when interpreting pre-dawn $x measurements in the field. It was often observed that at 'a predawn ifiv of -3 to -7 bars, the stomata would partially open in the predawn hours, resulting in Cs values approaching one-tenth of their full light value. Under these conditions, sufficient transpiration occurred to make predawn qX very sensitive to wind speed. Differences between predawn $x on calm and windy mornings as large as 3 bars were observed.

The second factor depended solely on the predawn xylem potential and controlled the maximum stomatal conductance (Cmax) observed during the diurnal cycle. This relationship could not be adequately examined in the forest due to untimely late season rains during the three years that field studies were conducted, and was investigated using potted trees. As predawn $x decreased below -7 bars in control trees and about -10 bars in fumigated trees, a drastic reduction in Cmax and Pn was observed. In trees kept in filtered air, Cmax was decreased from 0.36 to 0.036 cm/s by the decrease of predawn $x from -5 to -15 bars. Since the majority of the tree was kept in the dark during the measurement, the relationship between Cs and $x at QX values greater than can normally be observed in nature (due to root and xylem resis- tance) were examined. Conductance and Pn of fumigated trees in this region was not significantly higher than that observed at potentials associated with full illumination. Reductions in GaXof 25, 31, and 44 percent were measured for slight, moderate, and severely injured needles. Net photosynthesis for the same needle injury classes was reduced by 38, 54, and 69 percent from the 12.9 mgco2/dir -h rate measured in trees which had not been exposed to ozone.

Oxidant Impact on Ponderosa and Jeffrey Pine Foliage Decomposition1

2J. N. Bruhn, J. R. Parmeter, Jr., and F. W. Cobb, Jr.

Litter decomposition was studied on four plots located along the oxidant dosage gradient in the San Bernardino Mountains (SBNF). Precipitation decreased with decreasing oxidant dosage along this gradient, while forest floor-level solar radiation and temperature ir .eased. Ponderosa (Pinus ponderosa Dougl.) a1.d Jeffrey pine (Pinus Jeffrey! Grev. & Balf.) dominated the most and least severely impacted sites, respectively. Nylon mesh envelopes of fresh-fallen litter were exchanged among healthy and sick trees on the four study sites. Decomposition was measured as percents overall and nutrient (N, P, K. Ca and Mg) weight loss.

During the first two years of decomposition, its rate at each site was directly related to precipitation and oxidant dose. While site moisture apparently dominates litter decomposition, evidence suggests that oxidant injury to live needles is directly related to the rate at which they decompose. One year weight loss of ponderosa pine litter was negatively correlated (P .05) with the oxidant injury scores (O.I.S.)(Miller 1973) of litter source trees. One year weight loss by litter of both species was negatively correlated (P .05) with the O.I.S. of litter destination trees.

Live needle internal microflora may be initi- ated in the foliar bud and can be thought of as pioneers in a succession of microorganisms re-sponsible for litter decomposition. Microbial populations involved in foliage decomposition were studied via incubation of surface-sterilized live and litter needles on water agar. Eight trees from each of two central Sierra Nevada sites, Stanislaus National Forest (SNF) and Blodgett Experimental Forest (BEF), were included for comparison with the 15 SBNF study trees. Both taxo- nomic richness and population density increased with needle age. Both parameters increased similarly with age on all four SBNF sites. However, both parameters increased faster on the somewhat less oxidant-impacted BEF, and both parameters developed fastest on the least oxidant-impacted site (SNF).


2~nstructor of Forest Pathology, Michigan Technological University, Houghton, Mich.; Pro- fessor and Associate Professor of Plant Pathology, respectively, University of California, Berkeley, Calif.

Because not all fungi recorded in incub ation studies were identified, they are individually referred to as categories rather than species. Live SNF foliage yielded approximately twice as many fungus categories (60) as foliage from any other site. The two BEF plots harbored a few more categories (29 and 32) than did HV (27), the healthiest SBNF site. HV, in turn, provided more categories than any other SBNF site (15 to 20). Similar effects were not evident in forest floor litter. Oxidants apparently affect live needle microflora in two ways. By reducing needle lon- gevity, internal microflora development is prema- turely truncated. It also seems likely that oxidants further reduce the variety of fungi coloniz- ing live pine foliage by eliminating susceptible species. Insofar as community functional properties are stabilized by a combination of species adaptability and community diversity, reduction of live foliage microfloral diversity by oxidants is viewed as weakening the functional stability of these communities. The significance of such weakening is unknown.

In a growth chamber experiment, propylene oxide- sterilized pine needles were incubated on moist forest floor organic matter from either Che SNF or one of the SBNF sites. No meaningful differences in weight loss developed between treatments over 22 weeks, showing that oxidants to date had not significantly impaired the abilities of study-site microflora to cause litter weight loss. In a sec-cond growth chamber experiment, propylene oxide- sterilized pine needles were incubated on a uniform moist forest floor organic matter mixture in either filtered air or filtered air enriched with 20pphm ozone 8 hours daily for 14 weeks. The weight loss difference between treatments did not reach significance ( .05 P .01). Any effect in the field would be slight and probably limited to surface litter during moderate to severe oxidant episodes.

Acknowledgments: This project was funded in part with federal funds from the Environmental Protection Agency (E. P. A.) under contract number 68-03-0273.

LITERATURE CITED

Miller, P. R. 1973. Oxidant-induced community change in a mixed conifer forest. In Air pollution damage to vegetation. p. 101-117. Advances in Chemistry Series, Number 122. American Chemical Society.

Integrated Lake-Watershed Acidification Study

Carl W. Chen and Robert A. olds stein'

OBJECTIVES

The Integrated Lake-Watershed Acidification Study (ILWAS) was designed to determine the ecological effects of acid rain under natural conditions (EPRI, 1979, Goldstein et al., 1980). Since the most widely reported effect of acid rain has been the acidification of lake water leading to elimination of fish, it is of interest to learn how and why the ecosystem becomes acidified by acid rain.

Three forested watersheds (Panther, Woods, and Sagamore) within 15 km of each other in the Adirondack Park region of New York were selected for investigation. Each watershed has different configurations and characteristics. Principle hypothesis of the study is that these differences may lend to different pH dynamics, i-e., Panther Lake alkaline, Woods Lake acidic, and Sagamore Lake in-between.

This research will produce a comprehensive data base for the three watersheds covering a period of almost 4 years, a series of interpretive reports, and a calibrated and verified mathematical model. The wealth of understanding gained and the mathematical model developed will be readily applicable to other lake basins.

APPROACH

ILWAS couples field investigation with theoretical modeling. The interactions between the model and the field research are practiced in an interactive manner, each influencing and strengthening the other. Other research findings on mechanisms and rates of acidification processes are integrated into the model formulations.

FIELD PROGRAM

The watershed ecosystem is envisioned to com- prise a cascade of basic compartments: atmosphere, canopy, snowpack, catchment, soil layers, bogs, stream segment and lake. These are the compartments that the acid rain must pass through before it reaches lake outlet. As it passes through each compartment, biogeochemical processes acting in


2~ice-~resident,Tetra Tech, Inc. , Lafayette, California; Program Manager, Electric Power Research Institute, Palo Alto, California

series and in parallel will produce or consume acids and will release chemicals that shift the pH and other chemical equilibrium.

-Meteorology1 -Air duality

Rain Quality

-Throughfall Chemistry

-Hydraulics -Geochemistry - Microbial Processes (& Lab)

Hydrology-Aquatic Chemistry

Hydrology

-Aquatic Chemistry

- Paleoecology

Hydrology

Figure 1--Field Program Components

Field surveys are being conducted to character- ize the properties of the basic ecosystem compartments in each watershed. At selected locations, measurements are made for ambient air quality, the quantity and quality of waters that move through the system from tree top to lake outlet (see fig. 1). Data are collected monthly, weekly, synoptic, and once only, depending on the parameters and their temporal variability. The field program began in 1977 and will be completed in 1981.

MODELING

The model organizes the data into an integrated theoretical framework (Goldstein et al., 1980). The model also serves as a vehicle to check the consistency of theory and data from rainfall quantity to lake outlet quality. Eventually, the model may provide scientific answers to such management questions as: What will and will not happen if a certain air quality standard is imposed, and if the acidity of precipitation is increased or decreased.

The model flowchart shows the computation se-quence (fig. 2 ) . The model calculates dry deposition as a function of ambient air quality and simulates the quantity and quality of water in throughfall, soil horizons, bogs, stream, lake, and lake outlet (Chen et al., 1978). All impor- tant acidification processes are included in the model.

Ambient air quality

Basin properties

Dry deposition Exudate

Calculate Throughfall chemistry

Snow accumulation Snowmelt Ion-teaching

Calculate . Soil moisture Vertical infiltration Lateral outflow

+ Organic decomposition Nutrient uptake

.Weathering Cation exchange Equilibration (At-sys, etc.)

Quantity and quality of H20 through stream

Figure 2--Model Flowchart

The model uses a network of compartments to account for spatial variability of ecosystem. It updates meteorological conditions daily and ambient air quality weekly. The calculations are performed on a daily time step to simulate the dynamic responses of ecosystem throughout years. Graphic outputs are provided to facilitate inter- pretation.

PRELIMINARY FINDINGS

Data indicate that the H+ deposition rates are seasonal and are approximately the same for all three watersheds (Johannes and Altwicker, 1980). The seasonal pattern of H+ deposition seems to follow that of SO4 deposition (Johannes, 1980). The deposition rates of various ions in acid rain as measured at seven ILWAS stations correlate well with those measured at the nearby MAP3S stations. This is significant because it suggests that acid rain data from regional monitoring stations may be used to perform preliminary calcula- tion of acid rain effect for a new site.

The pH at Panther Lake inlet is normally 7.3 to 7.5 throughout the year. The pH at the outlet is similar except during the snowmelt periods. Dur- ing that period, pH drops to as low as 5.0. Some- thing must have happened in the lake. Alterna- tively, it was argued that the inlet was only a small spring, not representative of all inflows.

The pH profiles measured in the lake show that only surface water is acidified during the period of snowmelt (Hendrey et al., 1980). What is the source of H+ ions that acidify the lake surface?

To resolve the puzzle, the model was used to help trace the source of water at the outlet. The model was first calibrated to the Panther Lake basin (Chen and Goldstein, 1980). After that, precipitation falling directly on lake surface is set to zero. This allows estimation of the con- tributions of this input to the total observed outflow. Approximately two-fifths of the peak flow can be accounted for by the direct precipitation to the lake surface. During that period, lake water is inversely stratified with respect to temperature. Direct precipitation which has a pH of 3.8 to 4.2 quite possibly is deposited right on the surface to acidify the lake surface water (pH 5.0). Another possible explanation is surface runoff resulting from snowmelt which has a high acidity (Galloway et al., 1980).

The significance of the capability to manipu- late the model to examine the effect of a single process on the integrated response of the ecosystem should not be overlooked.

LITERATURE CITED

Chen, C.W., S.A. Gherini, and R.A. Goldstein. 1978. Modeling the Lake Acidification Process. In Ecological Effects of Acid Precipitation, - Report of a Workshop, Galloway, United King- dom, September 4-8, 1978, ed. M.G. Wood, Electric Power Research Institute, Palo Alto, CA, U.S.A., EA-79-6-LD.

Chen, C.W., and R.A. Goldstein. 1980. "Techniques for Assessing Ecosystem Im- pacts of Air Pollutants." & Proc. Inter- national Conference Air Pollutants and their Effect on the Terrestrial Ecosystem [May 10- 17, 1980, Banff, Alberta, Canada].

EPRI Technical Work Statement for the Integrated Lake-Watershed Acidification Study RP 1109. 1979. Electric Power Research Institute, Palo Alto, California.

Galloway, J.N., C.L. Schofield, G.R. Hendrey, and A.J. Johannes. 1980. "Sources of Acidity in Three Lakes Acid- ified During Snowmelt." In Proc. of Inter- national Conference on the Ecological Impact of Acid Precipitation, [March 11-14, 1980, Sandefjord, Norway].

Goldstein, R.A., C.W. Chen, S.A. Gherini, and J.D. Dean. 1980. A Framework for the Integrated Lake- Watershed Acidification Study. & Proc. of International Conference on the Ecological Impact of Acid Precipitation, [March 11-14, 1980, Sandefjord, Norway].

Hendrey, G.R., J.H. Galloway, and C.L. Schofield. 1980. "Temporal and Spatial Trends in the Chem- istry on the Ecological Impact of Acid Pre-

cipitation." Proc. of International Con- ference on the Ecological Impact of Acid Precipitation, [March 11-14, 1980, Sandef jord, Norway] .

Johannes, A.H., and E.R. Altwicker. 1980. "Atmosphere Imputs to Three Adirondack Lake Watersheds." 3 Proc. of International Conference on the Ecological Impact of Acid Precipitation, [March 11-14, 1980, Sandefjord, Norway] .

Photosynthesis and Stomatal Response to Light and Temperature in Ponderosa Pine Exposed to Long-Term Oxidant Stress1

P a t r i c k I.Coyne and Gai l E. ~ i n ~ h a m *

Seasonal courses (May t o October 1977) o f gross photosynthes is ( c a l c u l a t e d from CO2 uptake) and stomatal conductance were charac te r i zed as a f u n c t i o n o f l i g h t and gross and n e t photosynthes is were charac te r i zed as a f u n c t i o n o f temperature (May and J u l y 1978) i n a s tand o f ponderosa p i n e (Pinus ponderosa m.)i n t h e San Bernardino Na t iona l Forest . The CO2 d i f f u s i o n pathway was p a r t i t i o n e d i n t o i t s stomatal and r e s i d u a l (mesophyll , carboxy la t i on , e x c i t a t i o n ) res i s tance components f o r c o n d i t i o n s o f l i g h t s a t u r a t i o n and 20 C. These t r e e s have exper i - enced l o n g term o x i d a n t fumigat ions f rom C a l i f o r - n i a ' s South Coast A i r Basin s ince t h e i r e s t a b l i s h ment f o l l o w i n g f i r e i n t h e mid-1950's. Nine trees were s t r a t i f i e d f o r comparative s tud ies i n t o three ch ron ic i n j u r y c lasses ( I - s l i g h t i n j u r y , I 1 -moderate, I 1 1 - severe) hav ing s i m i l a r ox idan t i n j u r y symptoms based on t h e sco r ing system o f P. R. M i l l e r .

Maximum o r l i g h t sa tu ra ted gross photosyn- t h e t i c r a t e s (Pmax) and photochemical conversion e f f i c i e n c i e s (dP/dI ) I=o were h ighes t i n t h e cur - r e n t needles and decreased w i t h i nc reas ing nee- d l e age and w i t h season. D i f fe rences among nee- d l e age c lasses w i t h i n an i n j u r y c l a s s d iverged as t h e season progressed i n d i c a t i n g an acce le r - a t i o n o f senescence b y ozone. Maximum stomatal conductances (Cmax) and stomatal s e n s i t i v i t y t o i nc reas ing 1 i g h t (dC/dI) I=o d u r i n g opening f o l - lowed a s i m i l a r t r e n d t o Pmax and dP/dI except i n t h e c u r r e n t needles i n which Cmax and dC/dI were h i g h e s t i n t h e severe ly i n j u r e d t rees . Th is suggests a p o s s i b l e f a c t o r c o n t r i b u t i n g t o d i f - f e r e n t i a l ozone s e n s i t i v i t y i n t h i s stand. The r a t i o o f t h e stomatal r e s i s t a n c e f o r CO2 ( r l ) t o t h e t o t a l r e s i s t a n c e (r', s tomata l+res idua l ) decreased w i t h o x i d a n t i n j u r y , i nc reas ing 'need le age, and season suggest ing t h a t l o s s o f photo- s y n t h e t i c c a p a c i t y r e s u l t e d more from 1 i m i t a t i o n s a t t h e c h l o r o p l a s t s than from res i s tance t o CO2 d i f f u s i o n through t h e stomata.

Temperature optima (Top ) f o r photosynthesis were s i m i l a r i n a l l i n j u r y c lasses and averaged

'presented a t t h e Symposium on E f f e c t s o f A i r P o l l u t a n t s on Mediterranean and Temperate Fores t Ecosystems, June 22-27, 1980, R ivers ide, C a l i f o r n i a , U.S.A.

2 ~ 1 a n t P h y s i o l o g i s t , Southern P l a i n s Range Research S ta t i on , USDA/SEA/AR, Woodward, Okla.; and Environmental S c i e n t i s t , Lawrence Livermore Laboratory , Livermore, Cal i f .

^h is work was supported by a U.S. Dept. o f Energy c o n t r a c t (W-7405-ENG-48) w i t h Lawrence Livermore Laboratory .

about 20Â° i n May and 25OC i n J u l y . L i g h t r e s p i - r a t i o n (es t imated as Pgross-Pnet) was h i g h e s t i n hea l thy younq needles and increased w i t h tempera- t u r e from 5Â° t o To t and then l e v e l e d o f f between Topt and 35OC. ~lthough l i g h t r e s p i r a t i o n was i n v e r s e l y r e l a t e d t o ox idan t i n j u r y , t h e r a t i o o f Pnet/P ss tended t o decrease w i t h o x i d a n t injury. ~ ~ ~ a r e n t ? ~ox idan t s t ressed t r e e s n o t o n l y had reduced r a t e s o f CO2 f i x a t i o n , b u t r e t a i n e d a smal l e r p r o p o r t i o n o f a s s i m i l a t e d carbon a f t e r r e s p i r a t i o n losses. Summary data f o r s e l e c t parameters are compared i n Table 1.

Table 1--Comparison o f s e l e c t parameters normal- i z e d by d i v i d i n g each mean by t h e maximum mean va lue i n each column.

I n j u r y Needle 1977 Means Class Age Pmax ] Cmax lr;/r1

I 0 1.00 0.89 1.00 1 0.61 0.84 0.80 2 0.32 0.62 0.59

II 0 0.92 0.92 0.82 1 0.53 0.75 0.71 2 0.17 0.38 0.40

III 0 '0.79 1.00 0.59 1 0.35 0.57 0.45

Max. value1 8.30 0.24 0.29

J u l y 1978 Pgross-Pnet

1.00 0.60 0.35 0.95 0.51 0.18 0.94 0.35 2.46

^ p a r meters d e f i n e i n t e x t . Un i t s : P, mg CO2 g -7t-1-1; C, cm s-y ; r, s cm-1; age i n years.

The d i f f e r e n t i a l response i n photosynthes is and stomatal conductance among these f i e ld -g rown ponderosa p ine t r e e s growing i n a common env i ronment i n d i c a t e d t h e presence o f eco typ ic v a r i a t i o n i n ozone s e n s i t i v i t y . The d i f f e r e n c e s among i n j u r y c lasses were man i fes t as an a c c e l e r a t i o n o f t h e normal d e c l i n e i n CO2 f i x a t i o n and stomatal conductance assoc ia ted w i t h needle aging. Par t i c -u l a r l y ev iden t were t h e premature senescence and absc iss ion o f needles o c c u r r i n g a t about t h e t ime gross CO2 uptake dropped t o 10 percent o f t h e p o t e n t i a l f o r c l a s s I c u r r e n t needles w i t h o u t f o l i a r i n j u r y symptoms. T h i s occurred a t i n t e -gra ted i n c i d e n t ozone doses as low as 450 ppm-h i n severe ly i n j u r e d t r e e s ( c l a s s 111) o r as h i g h as 800 ppm-h i n s l i g h t l y i n j u r e d t r e e s ( c l a s s I ) .

A probable scener io f o r ox idan t e f f e c t s can be descr ibed. As f o l i a r i n j u r y symptoms increase, photosynthet ic capac i t y and n e t carbon accumula- t i o n pe r u n i t l e a f mass o r area, mass and area per needle, needle mass per u n i t area, and number o f needle whor ls r e t a i n e d pe r t r e e dec l i ne . These f a c t o r s c o n t r i b u t e t o t h e steady l o s s o f t r e e v igo r , weakening them t o t h e p o i n t o f v u l - n e r a b i l i t y t o pathogenic organisms such as r o o t r o t t i n g f u n g i and bark beet les .

----- --

The Effect of Air Pollution on Western Larch as Detected by Tree-Ring Analysis1

Car l A . Fox and Thomas H. Nash 1112

The number of p u b l i c a t i o n s i n r e c e n t y e a r s d e a l i n g w i t h t h e e f f e c t s o f a i r p o l l u t i o n on p l a n t s has been voluminous. A v a s t m a j o r i t y of t h e s e have d e a l t wi th t h e e f f e c t s of shor t - te rm (hours o r days) fumiga t ions on p l a n t response. I n con-t r a s t t o t h e s e s t u d i e s , t h e r e i s r e l a -t i v e l y l i t t l e i n f o r m a t i o n on t h e l ong -term, cumulat ive e f f e c t s o f a i r p o l l u t i o n over decades. To examine t h e s e long-term e f f e c t s , a dend roeco log ica l ( t r e e - r i n g ) a n a l y s i s was employed t o a s s e s s t h e growth r e s p o n s e o f w e s t e r n l a r c h ( L a r i x o c c i d e n t a l i s N u t t . ) t o s u l f u r d i o x i d e . U t i l i z a t i o n of dend roeco log ica l t echni -ques provided a means f o r q u a n t i t a t i v e l y removing t h e e f f e c t o f c l i m a t e on t h e g r o w t h r e s p o n s e o f l a r c h a n d , t h u s , pe rmi t t ed a n examinat ion of t h e r e s i d u a l g r o w t h r e s p o n s e i n t e r m s o f l o c a l s i t e f a c t o r s , s p e c i f i c a l l y s u l f u r d i o x i d e .

F i v e wes te rn l a r c h s tudy s i t e s were l o c a t e d i n t h e Columbia River Val ley n e a r t h e lead-z inc s m e l t e r a t T r a i l , B r i t i s h C o l u m b i a . T h i s p a r t i c u l a r l o c a t i o n r e p r e s e n t s a unique s tudy a r e a i n t h a t t h e s u l f u r d i o x i d e g r a d i e n t h a s been w e l l documented , b o t h o v e r s p a c e and t i m e , s i n c e s m e l t i n g a c t i v i t y began i n 1896 .

S u l f u r e m i s s i o n s f rom t h e s m e l t e r i n c r e a s e d i n t h e e a r l y 19001s , reached a maximum i n 1930, and r e s u l t e d i n a con-commitant dec rease i n annual t r e e growth. A f t e r 1930 , s u l f u r e m i s s i o n s d e c r e a s e d d r a m a t i c a l l y w i th t h e implementat ion of p o l l u t i o n abatement measures. However, t h e growth response of wes te rn l a r c h t o t h e d e c r e a s e d s u l f u r e m i s s i o n s was n o t immediate, and r e f l e c t e d t h e low frequency n a t u r e o f t h e v a r i a n c e o f t h e s u l f u r d i o x i d e e f f e c t on t r e e growth.

p r e s e n t e d a t t h e Symposium on E f f e c t s of A i r P o l l u t a n t s on Mediterranean and Temperate F o r e s t Ecosystems, June 2 2 - 2 7 , 1980, R i v e r s i d e , C a l i f o r n i a , U.S.A.

^ ~ e s e a r c hS c i e n t i s t , Southern C a l i f o r n i a Edison Company, Rosemead, C a l i f o r n i a ; Assoc i a t e P r o f e s s o r of Botany, Arizona S t a t e U n i v e r s i t y , Tempe, Arizona.

C o r r e l a t i o n and r e g r e s s i o n a n a l y s e s were u t i l i z e d t o d e v e l o p m u l t i v a r i a t e models f o r t h e l a r c h s tudy s i t e s sampled a t v a r y i n g d i s t a n c e s f r o m t h e T r a i l sme l t e r . Cl imat ic models developed f o r t h e c o n t r o l s i t e ( t r e e - r i n g ) chronology were app l i ed t o s i t e chronologies l o c a t e d w i t h i n t h e s u l f u r d iox ide a f f e c t e d a r e a t o remove t h e e f f e c t s o f c l i m a t e on t r e e growth and examine t h e r e s i d u a l response of t h e system. The p a t t e r n of t h e r e s i -d u a l s c l o s e l y resembled t h e s u l f u r emis-s i o n s f r o m t h e s m e l t e r w i t h t h e m o s t n e g a t i v e r e s i d u a l s o c c u r r i n g when s u l f u r emiss ions were g r e a t e s t .

F u r t h e r r e g r e s s i o n modeling i d e n t i -f i e d t h e r e l a t i v e i m p o r t a n c e o f s u l f u r emiss ions , p r i o r y e a r ' s growth, tempera-t u r e , and p r e c i p i t a t i o n t o a n n u a l f r e e g rowth . I n t h o s e s i t e s c l o s e s t t o t h e s m e l t e r , s u l f u r emiss ions accounted f o r t h e g r e a t e s t p ropor t i on of t h e v a r i a n c e c a l i b r a t e d b y t h e r e g r e s s i o n models. A s d i s t a n c e from t h e s m e l t e r i n c r e a s e d , t h e va r i ance a t t r i b u t a b l e t o s u l f u r emiss ions decreased i n each s i t e model. I n a l l of t h e s i t e models, t empera ture , p a r t i c u l a r l y summer t e m p e r a t u r e , a p p e a r e d t o b e a primary l i m i t i n g c l i m a t i c f a c t o r . P r i o r g rowth a l s o a c c o u n t e d f o r c o n s i d e r a b l e va r i ance i n t h e models wi th p r e c i p i t a t i o n v a r i a b l e s a p p e a r i n g t o be o f l e s s e r importance i n e x p l a i n i n g t h e v a r i a n c e of t h e s i t e chronologies .

The r e s u l t s of t h i s s t u d y demon-s t r a t e t h e a p p l i c a b i l i t y of t r e e - r i n g a n a l y s i s i n i d e n t i f y i n g and q u a n t i f y i n g t h e long-term e f f e c t s of a i r p o l l u t i o n on f o r e s t communities. It a l s o p rov ides a b a s i s f o r examining t h e i n t e r r e l a t i o n s h i p s between a i r p o l l u t i o n , c l i m a t e , and t r e e growth.

Acid Rain: Threshold of Leaf Damage in Eight Species from a Forest Succession1

2B.L. Haines, M. S te fan i , and F. Hendrix

Eight p l a n t spec ies were subjected t o a r t i - f i c i a l a c i d r a i n s of pH 2.5, 2.0, 1.5, 1.0, and 0.5 i n order t o determine t h e threshold f o r and symptoms of damage. I n a previous study a r t i - f i c i a l ac id r a i n s of pH 5.5, 4.5, 3.5, and 2.5 f a i l e d t o produce symptoms of damage. The pre- s e n t s tudy was designed t o extend t h e pH range. The p l a n t s were E r e c h t i t e s , Robinia, Pinus, Quercus, Carya, Liriodendron, &, and Cornus from t h e Fores t s e r v i c e ' s owee eta ~ ~ d r o l o ~ i c -Laboratory near Frankl in , North Carolina. Du-p l i c a t e 0.01 m l drops of each of t h e 5 simulated ac id r a i n s o l u t i o n s were appl ied t o a s i n g l e mature l ea f on each of two p l a n t s of seven spe- c i e s . The e n t i r e experiment was performed twice. I n Pinus needle t i p s were immersed i n t h e solu- t ions . The s i z e s of n e c r o t i c spo ts a r e shown i n Fig. 1. Droplets of pH 2.0 produced brown nec- r o t i c s p o t s on a l l spec ies except Pinus whi le d r o p l e t s of pH 1.0 produced necroses on leaves of a l l spec ies examined. Pinus needles were dam-aged a t pH values between 1.0 and 0.5. Damage was confined t o younger needles and was evidenced by browning and col lapse. For angiosperms t h e s i z e s of n e c r o t i c s p o t s increased with decreasing pH. This suggests t h a t t h e l e a f has some buf fe r ing capaci ty which was p rogress ive ly overcome by increas ing d r o p l e t a c i d i t y . Comparison of re-s u l t s wi th l i t e r a t u r e suggests t h a t developing leaves a r e more e a s i l y damaged than a r e mature leaves used i n t h i s study. No successional t r ends i n s u s c e p t i b i l i t y were observed.

p r e s e n t e d a t t h e Symposium on E f f e c t s of A i r P o l l u t a n t s on Mediterranean and Temperate Forest Ecosystems, June 22-27, 1980, Rivers ide, Ca l i fo rn ia , U.S.A.

' ~ s s i s t a n t Professor of Botany, Department of Botany, Univers i ty of Georgia, Athens, GA 30602; Graduate Research Ass i s tan t i n P lan t Pathology, and Prof. of P lan t Pathology, Dept. of P lan t Pathology and Genetics, Univers i ty of Georgia, Athens, Georgia 30602. Research supported by U.S. EPA Grant R80530510 and NSF g r a n t s DEB 7619930, DEB 7705324A01 and DEB 7904537 t o t h e Univers i ty of Georgia.

The volume weighted average r a i n f a l l pH f o r Coweeta i s 4.6 with observat ions ranging from 3.2 t o 5.9. Because t h e pH s c a l e i s logar i thmic with a decrease i n 1 pH u ?it corresponding t o a 10-fold inc rease i n t h e H concentrat ion, i t i s apparent t h a t a 100-fold inc rease i n t h e volume weighted average concentrat ion of H a t Coweeta would change t h e pH from 4.6 t o 2.6 which is near t h e threshold of damage. However, t h e extremes may be f a r more c r i t i c a l than t h e volume weighted average. With t h e lowest pH va lue recorded f o r Coweeta being pH 3.2, merely a 10-fo ld inc rease i n a c i d i t y t o pH 2.2 i n a s i n g l e spr ing o r summer storm seems l i k e l y t o b r ing damage o r death t o mature leaves of t h e flowering p l a n t s a t Coweeta.

PLANT SPECIES MD L I F E FORM pH OF DROPLETS APPLIED

0 . 5

ERECHTIKS HlEMClFOLIA(L) RAF. HERBACEOUS W E D (N - 6)

P U U S STROBUS L. TREE ( N - 8 )

ROBIHIA PSEUDO-ACACIA La SHRUB TO TREE ( N - 6 )

ACER RUBRUH L. THE ( N = 0

1 . 0 1 . 5 2 .0 2.5

Figure 1. Average diameter i n mm of n e c r o t i c s p o t s on leaves subjected t o d r o p l e t s of 5 pH l e v e l s . (*) Spot diameters no t measured on needles, s e e t e x t f o r desc r ip t ion of damage.

Prioritization of Research on Air Quality Related Resources of the National Parks1

E. A. Howard, L. If. Boyd, W. M. Brock, D. W. Morse, S. S. Shin and K. L. steel-sabo2

The National Park Service (NPS) has the legal responsibility and authority to preserve and protect the resources of lands under its jurisdiction. Air pollution has been recognized as a significant threat to the parks and the 1977 Amendments to the Clean Air Act provided the Service the authority and responsibility to protect resources that are air quality related. The NPS Air Quality Office intends to conduct research programs to determine air pollution effects, to emphasize the use of sensitive receptors to detect effects, as well as to ensure that scientific evidence is readily a- vailable when NPS must make determinations of adverse effects. These efforts are subject to time and funding limitations and therefore guide- lines on setting research priorities are being developed.

The first step in establishing cause and effect relationships is to identify the pollutants that may. affect park resources (fig. 1). Pollutants from existing or planned sources may be identified by monitoring or estimated from permit requirements. If sources are not known, pollutants must be identified through some early warning process or on the basis of the potential development of regional natural resources. Existing sources of air pollutants that may affect the natural or cultural resources of park units must be ranked according to pollutant type, concentration, frequency, and duration of exposure of the resource. The rankine must also incorporate the estimated lead time before new pollutant sources begin operation. The identification and ranking of pollutant sources is necessary to economize the search for potential effects.

The identified pollutants are then used as a basis of comparison between the list of resources present on a park unit and the literature or current research information on resource susceptibility (fig. 1). The presence or absence of information on park resources must be incorporated into the setting of priorities. If these data are unavail- able, obtaining information on air quality related resources may be the most pressing need. If the resource inventories are available, then the information from these inventories is used in the comparison between resources present and those


2~hysical Scientist and Environmental Protec- tion Specialists, Denver Service Center, National Park Service, U.S. Department of Interior, Denver, Colorado.

that are susceptible to the effects of air pollution. The availability of current research information or literature on susceptibility must be similarly considered in establishing research priorities. Time constraints on recovering information or research results on air quality effects on natural ecosystems has prompted the development of a quick access annotated bibliography that uses a codin8 system based specifically on natural and cultural resources of NPS units. The bibliography has been used on several occasions to provide lists of references in support of litigation and testimony for hearings.

Setting priorities for research on air quality effects is altered by other influences and constraints (fig. 1). Funding and time limitations must be incorporated into the prioritization. In- sufficient funding may cause postponement of the highest priority research until these requirements can be integrated into the budget cycle. Time constraints also have considerable influence on priority setting. Substantive scientific data on air quality effects cannot be produced within the short time schedules of hearings or litigation. The timing of the budget cycle creates difficulty in obtaining sustained funding for long-term effects research. Political requirements at the Washington level may override the regional prioritization. The setting of priorities must be continually updated in conjunction with any change imposed by these influences or constraints.

POLLUTANT SOURCES RANKED ACCORDING TO IMMINENCE AND DAMAGE

POTENTIAL

LISTS OF RESOURCES LITERATURE AND FOR PARKS OF THE RESEARCH INFOFNA-

REGION TION ON RESOURCE SUSCEPTIBILITY

OTHER INFLUENCES OR CONSTRAINTS

PRIORITIZE RESEARCH NEEDS

Figure I--Considerations in setting research priorities for air quality related resources.

Estimation of Adverse Effects of Air Pollution on Danish Forests1

2I b Johnsen

E f f e c t s o f air p o l l u t i o n on Danish f o r e s t s do probably on ly occur under cond i t ions , where SO2, NO,, and/or 03 a r e p r e s e n t t o g e t h e r , t h u s r e s u l t - i ng in s y n e r g i s t i c a c t i o n on t h e l eaves . The maximum observed monthly average urban immission of NOx and SO2 a r e w i t h i n t h e range f o r syner- g i s t i c a c t i o n he reof . I n r u r a l r e g i o n s on ly t h e most s e n s i t i v e s p e c i e s may be a f f e c t e d by combi- n a t i o n s of S02, NOx and 03. Oxidants, and 0 3 i n p a r t i c u l a r , probably p l a y a s t r o n g e r r o l e in r u r a l a r e a s s i t u a t e d in t h e o u t e r pe r iphe ry of c i t i e s . Here l e v e l s exceeding t h e v a l u e s a t which e f f e c t s on r a t h e r s e n s i t i v e s p e c i e s occa- s i o n a l l y occur dur ing summer time. Unstable s u p e r a d i a b a t i c c o n d i t i o n s combined wi th h igh i n s o l a t i o n l e a d t o h i g h 03 formation r a t e s , and h igh ground l e v e l S O ~ / N O ~l e v e l s a r e observed when h igh s t a c k emiss ions a r e t r a n s p o r t e d t o t h e ground r e l a t i v e l y c l o s e t o t h e source .

F l u o r i d e s a r e on ly o f importance in ve ry re-s t r i c t e d a r e a s around b r i c k f a c t o r i e s , f e r t i l -i z e r i n d u s t r i e s e t c . , and of minor s i g n i f i c a n c e i n r e l a t i o n t o Danish f o r e s t r y .

Heavy me ta l s and hydrogen i o n s r e s u l t i n i n d i r e c t e f f e c t s a s adver se e f f e c t s on t h e n u t r i - e n t s t a t u s of t h e s o i l and t h e s o i l mic rob ia l p rocesses . The map shows a r e a s of Denmark (shaded a r e a s ) where t h e s o i l i s be l i eved t o be most v u l n e r a b l e t o a c i d p r e c i p i t a t i o n ; it is reasonab le t o b e l i e v e t h a t t h e s e a r e a s a r e co- i n c i d e n t wi th those expected t o b e most a f f e c t e d by i n c r e a s i n g heavy me ta l l e v e l s in top s o i l due t o a tmospher ic f a l l o u t . The most v u l n e r a b l e s o i l s a r e i n t e r m e d i a t e between t h e ve ry pod- z o l i s e d s o i l s of t h e a l l u v i a l p l a i n s (Western J u t l a n d ) and brown e a r t h s / c l a y i s h s o i l s w i t h high b u f f e r c a p a c i t y , and are c h a r a c t e r i z e d by t h e i r h igh c o n t e n t of moraine sand.

p r e s e n t e d a t t h e Symposium on E f f e c t s of A i r P o l l u t a n t s on Mediterranean and Temperate F o r e s t Ecosystems, June 22-27, 1980, R ive r s ide , C a l i f o r n i a , U.S.A.

Assoc ia t e P r o f e s s o r of P l a n t Ecology, U n i v e r s i t y of Copenhagen, Denmark.

Areas of woodland in Denmark r e l a t e d t o s p e c i e s . 1976. - ( Numbers in 1000 ha. ) -Fagus s i l v a t i c a - 75 Res. Quercus robur 25 Res. Fraxinus e x c e l s i o r 9 Sens. Acer psuedoplatanus 5 Res. Other deciduous spp. 24 Deciduous t o t a l 138

P i c e a a b i e s Sens. P icea s i t c h e n s i s 173 sens . Abies spp . 2 7 Sens. Pinus mugo 3 0 Res. Other con i fe rous spp. 46 Coniferous t o t a l 276

Woodland t o t a l 4 14

Immission l e v e l s and th resho ld v a l u e s

-F

O3 -3(ugm , d i u r n a l means)

Urban 40-100. 50-100 25-50 0.5-5 Rural 10-40 5-20 25-200 0.2-0.5

S ing le 250 500 100 1 100 5 0

Comb. 50 5 0 100 50

F igure I--Areas of Denmark (shaded a r e a s ) dominated by moraine sand d e p o s i t s .

1

Changes in Southern Wisconsin White Pine Stands Related to Air Pollution Sensitivity1

David F. ~ a r n o s k y ~

Fif teen eastern white pine (Pinus strobus L. ) sample p lo t s consist ing of a t o t a l of 1523 t r e e s were establ ished within a 13 km radius of t h e coal-burning 1054 MW Columbia Generating Stat ion, located 40 km north of Madison, Wisconsin. The sample p lo t s were establ ished i n 1971 and observed frequently during t h e growing season for 4 years and then annually a t t h e end of each growing season fo r t h e next 5 years. These p lo t s consisted of plantat ions with t r e e s having uniform ages within each plantat ion but with t r e e s ranging i n age from 10 t o 40 years old across t he 15 p lo ts . Baseline study during the 4 years 'before the plant began operation i n 1975 showed t h a t some 10 percent of t h e white pine t r e e s were sens i t ive i n some degree t o ambient a i r pol lut ion a s determined by the presence of needle t i p h r n and/or chlorot ic dwarf symptoms i n one or more years. The sens i t ive t r e e s occurred randomly i n the p lo ts .

The most common type of a i r pol lut ion symptom found i n t h e 'baseline study was tipburn consist ing of reddish brown dieback (0.1 t o 3 cm i n length) on f i r s t -year needle t i p s . The sever i ty of symp-toms varied from t r e e t o t r e e and from year t o year. The most severely affected t r e e s had stunted tops , short needles, poor needle re ten t ion , and were cha rac t e r i s t i c of an a i r pollution-induced syndrome ca l led t h e chlorot ic dwarf disease. However, ch loro t ic mottling of new needles, com-mon t o t h e chloro t ic dwarf disease., did not occur. Tipburn symptom development usual ly began during t h e ear ly summer when t h e new needles were elon-gating. Thus, t r e e s 'began showing symptoms i n ear ly t o mid June, and symptoms developed throughout t h e growing season.

Continuous a i r monitoring for su l fur dioxide ('SO2) and ozone to3), 'begun i n 1973 and continued t o t h e present time, revealed the common occurrence of SO2 and O-; concentrations i n t h e range of 0.4 t o 5.0 pphm fo r 1t o 3 hours during t h e summer months. Maximum one-hour averages recorded during t h e study were 11pphm SO2 and 13 pphm 03. These l eve l s , while low i n terms of a i r qual i ty standards, have "been shown t o be within the range of concentrations of these pol lu tants reported t o i n ju re genetical ly sens i t ive eastern white pine t r e e s i n control led fumigations.

p re sen ted a t the Symposium on Effects of A i r Pol lutants on Mediterranean and Temperate Forest Ecosystems, June 22-27, 2980, Riverside, California, U.S.A.

o ore st Geneticis t , New York Botanical Garden Cary Arboretum, Millbrook, N.Y.

During the 5 years since the power plant began operation, there have been no detectable d i f fer - ences i n t he occurrence o r sever i ty of symptoms. With only a few exceptions, t he same t r e e s have shown symptoms a f t e r t h e plant began operation a s before it s ta r ted . However, mortal i ty has reduced intermediate genotypes (those injured i n 1 or 2 years of t he 9 year study) by 4.7 percent and the sens i t ive genotypes (those injured i n 3 o r more years ) by 10.4 percent (Table 1). In comparison, only 2.0 percent of t h e to lerant t r e e s have died during the course of t he study. Most of t h e mor- t a l i t y of t h e sens i t ive genotypes was apparently due t o t h e i r being slower growing and thus unable t o compete fo r l i g h t , water, and nut r ien ts with t h e i r neighboring t r ees . As a r e s u l t , t h e white pine stands studied a re undergoing a gradual t ran- s i t i o n towards having air-pollut ion to l e ran t genotypes dominate.

Acknowledgments: This study was supported i n part by Grant R803971, Environmental Protection Agency, and by the Wisconsin Pi-iblic Service Corp., t he Madison Gas and Elec t r ic Co., t he W i s -consin Power and Light Co., and t h e College of Agricul tural and Life Sciences, University of Wisconsin.

Table I ~ M o r t a l i t y over a 9-year period of eas t -ern white pine t r e e s d i f fer ing i n a i r pol lu t ion sens i t i v i ty .

A i r Pollution sens i t iv i ty1 If Trees Died Mortal i ty

Tolerant Intermediate Sensitive

Totals :

l ~ h esens i t i v i ty rankings were based on t h e following: to lerant t r e e s did not have a i r - pollution-induced t ipburn symptoms during the course of t he study; intermediate t r e e s had symptoms for 1or 2 years; and sens i t ive t r e e s had symptoms for 3 or more years.

Effect of Os and Os + NO2on Growth of Tree Seedlings1

Lance W. ~ r e s s ~

Seedlings of 10 eastern forest tree species were exposed to 0.05, 0.10, or 0.15 pprn 0 and seedlings of 7 tree species were exposed to 0.10 pprn 0

3 and/or

0.10 pprn NO 2 in 6 hr/day exposures for 28 consecu-

tive days. The exposures were performed when the seedlings were 2-4wk-old in indoor exposure chambers of the CSTR design.

The Environmental Protection Agency has determined that the threshold for significant growth effects due to extended 0

3 exposures (7 hr daily

avg. for 2 no) for sensitxve vegetation is between 0.06 and 0.10 ppm. Three species in this study exhibited a threshold for significant suppressions in that range, while three other species exhibited a threshold for significant effects between 0.10 and 0.15 pprn (Table 1). However, two species exhibited a threshold for significant growth suppressions at or below 0.05 ppm. Those two species, loblolly pine and American sycamore, are probably the most im- portant of the species tested to the forest industry. The significant effects at 0.05 pprn 0 were not

3accompanied by foliar injury.

In previous studies there have been indications that low concentrations of NO

2 might be stimulatory

to plant growth or alleviate 0 phytotoxicity.3Similar indications were noted for some of the tree species in this study. Two species (white ash and green ash) exhibited greater growth in the NO

2treatment than the control, and the only significant interactive effects were significantly less than additive (sweetgum and white ash).

Stimulations of growth at low 0 concentrations3

have been noted in the past, and some species exhibited growth stimulations in this study (Table 1). However, apparent growth stimulations appear to be dependent in part on the plant species and the parameter being evaluated.

The relationship that these data have to field conditions is not clear. This study demonstrates the potential for adverse effects at pollutant concentrations below the current NAAQS, but future research will have to determine whether such effects can be detected in the field.


'~esearch Associate of Plant Pathology, Vir- ginia Tech., Blacksburg, Va. Currently Assistant Ecologist, Argonne National Laboratory, Argonne, 111.

Table 1. Height growth and dry weight expressed as percent of control for seedlings of 10 tree species exposed to 0.05, 0.10, or 0.15 pprn 0 for 6 hr/day

3for 28 consecutive days.

Percent of control

Species

Loblolly Pine '100a looa lOOa (Pinus taeda L.) 82 b 85ab 90ab

73 b 79 b 72 bc 59 c 74 b 64 c

Pitch Pine lOOa lOOa lOOa rigida Mill. )(P.- 96ab

87 b 94a 83a

84ab 77ab

74 c 78a 68 b Virginia Pine lOOa lOOa lOOa

(Lvirginiana Mill. )

95a 89a

98a 97a

120a 93a

86a 87a 86a Sweet gum lOOa lOOa l60a (Liauidambar 109a 9lab 88ab styraciflua L.) 71 b 76ab 65 bc

55 b 60 b 52 c Sycamore lOOa lOOa lOOa (Platanus 104a 84a 57 b occidentalis L.) 73 b 43 b 27 b

79 b 36 b 19 b Green Ash lOOa lOOa lOOa

(Lpennsylvanica Marsh.)

98ab 76 bc

86ab 7lab

86a 75a

70 c 64 b 75a White Ash lOOa 100 b lOOab {Fraxinus 112a 125a 11 la americana L.) 91a 92 b 87 b

85a 83 b 81 b Willow Oak lOOa lOOa 1OOa (Quercus phellos 99a 99a 94a L.) 96a 92a 83a

81 b 89a 83a Sugar Maple 100 b lOOa 1 OOab

(& saccharum 95 b 88a 161a L.) 108a 90a 116ab

88 c 5 8 b 69 b Yellow Poplar 100 b 100 b 1 OOa (Liriodendron 160a 147a 133a tulipifera L.1 108 b 11lab 96a

Values for each column/species followed by the same letter are not different at p = 0.05 according to the ~uncan's New Multiple Range Test.

Impact of Oxidant Air Pollution on Ponderosa and Jeffrey Pine Cone Production1

Robert F.

Cone product ion by ponderosa and J e f f r e y p i n e t r e e s 10 cm o r more i n dbh was assessed on 19 p l o t s l o c a t e d i n t h e San Bernardino Mountains of sou the rn C a l i f o r n i a . These p l o t s were e s t ab -l i s h e d a long a g r a d i e n t o f oxidant a i r p o l l u t i o n . Each t r e e was r a t e d annua l ly us ing an oxidant a i r p o l l u t i o n index based upon t h e number o f yea r c l a s s e s o f need les r e t a i n e d , t h e i r c h l o r o t i c con-d i t i o n , t h e i r l eng th and t h e amount o f branch m o r t a l i t y p r e s e n t . Th i s r a t i n g was made independent ly i n t h e upper and lower crown f o r each t r e e . Other t r e e c h a r a c t e r i s t i c s , e . g . , age, dbh, h e i g h t , were a l s o measured once dur ing t h e course o f t h e 6 yea r s tudy. Cones were v i s u a l l y counted w i t h i n t h e crown o f each t r e e each September and October.

Although seve re oxidant a i r p o l l u t i o n i n j u r y was a s s o c i a t e d wi th reduced cone product ion, t h e most impor tant c o r r e l a t e wi th cone product ion was crown c l a s s , i . e . , t h e p o s i t i o n of a t r e e ' s crown r e l a t i v e t o t h o s e o f i t s neighbors . Dom-i n a n t t r e e s bo re t h e g r e a t e s t p ropor t ion o f cones. I n ponderosa p i n e dominant t r e e s com-p r i s e d 32 pe rcen t o f t h o s e p resen t on t h e 19 p l o t s bu t bo re 80 pe rcen t o f t h e cones. When t h e dominant and codominant crown c l a s s e s were com-bined t h e y comprised 58 pe rcen t of t h e ponderosa p i n e s bu t bo re 96 pe rcen t o f t h e cones. J e f f r e y p i n e showed a similar p a t t e r n . I n both J e f f r e y and ponderosa p i n e , cone product ion inc reased s i g n i f i c a n t l y wi th age (Ho:b=O: ponderosa p ine ; dominant: 7 = -92.33 + 1.86 (Age), r2 = 0.811**; codominant: 7 = -74.48 + 1.077 (Age), r2 = 0.4216*: J e f f r e y p ine ; dominant: 7 = 4.74 + 0.434 (Age), r2 = 0.765**; codominant: 7 = -8.28. + 0.243 (Age), r2 = 0.7456**).

Three p a t t e r n s were observed: (1) I n dominant J e f f r e y p i n e s 130 y e a r s o r o l d e r fewer s e v e r e l y i n j u r e d t r e e s bore cones t h a n un in ju red ones ( l b F ( 4 , 25) = 11.98, p < 0.05) ; (2) i n dominant ponderosa p i n e s 130 yea r s o r o l d e r s e v e r e l y in - ju red t r e e s bore fewer c o n e s / t r e e than un in ju red ones (2a x2

f4l = 21.07, p < 0.005) ; and (3) i n

both dominant and codominant J e f f r e y and ponderosa p i n e s s e v e r e l y i n j u r e d t r e e s bore s i g n i f i - c a n t l y fewer cone crops t h a n un in ju red ones dur-ing t h e 6 y e a r s of t h e s tudy ( x 2 ' s va lues < 0.01 i n 5 c a s e s , < 0.05 i n 1 c a s e ) .

-

' p resented a t t h e Symposium on E f f e c t s of A i r P o l l u t a n t s on Medi ter ranean and Temperate F o r e s t Ecosystems, June 22-27, 1980, R ive r s ide , C a l i f o r n i a , U.S.A.

a s s o c i a t e P ro fesso r of Entomology. Divis ion o f B io log ica l Con t ro l , Un ive r s i ty o f C a l i f o r n i a , R ive r s ide , C a l i f .

~ u c k ~

PONDEROSA PINE100

80z-6 0

w 3 4 0

a 0 2o w a Or z

C Â ¥ O 0-1 2 3 4 5

JEFFREY PINE

Â ¤ 80 M CK * 6 00 a a -I 0 U 4 0 0" Q_ 20

0 1 2 3 4 5

100 8 o PONDEROSA PINE

100 JEFFREY PINE

SLIGHT SEVERE

SMOG INDEX

Fig. 1. Propor t ion o f t r e e s producing cones i n a given smog c l a s s . (a) Ponderosa p ine ; (b) J e f f r e y p ine .

Fig . 2. Propor t ion o f c o n e s / t r e e borne by t r e e belonging t o a given smog c l a s s . (a) Ponder-o s a p ine; (b) J e f f r e y p ine .

-- - -

Lichens as Air Quality Monitors1

P.D. Lulman R .J. Fessende9S.A. McKinnon

The Athabasca t a r sands , l o c a t e d i n a remote region i n nor theas te rn Alber ta , i n t h e boreal f o r e s t region o f Canada, con ta in v a s t r e se rves (approx. 600 b i l l i o n b a r r e l s ) o f bitumen. A t t h e p resen t time t h e r e a r e only 2 companies opera t ing i n t h e region, producing s y n t h e t i c crude o i l from t h i s bitumen, Suncor Inc . and Syncrude Canada Ltd. Suncor, which began production i n 1967, emits approximately 200-300 tonnes of SO2 per day. Syncr-ide, which began production i n 1978 and which i s l o c a t e d only 10 km from Suncor, has been emi t t ing about 50-100 tonnes per day. I n t h e next 10-20 years t h e r e is a good p o s s i b i l i t y t h a t many more companies w i l l begin opera t ing i n t h e region a s we l l . This has l e a d t o a concern about t h e e f f e c t s o f changes i n a i r q u a l i t y on t h e vege ta t ion o f t h e region. S ince l i c h e n s a r e known t o be more s e n s i t i v e t o a i r p o l l u t a n t s , p a r t i c u l a r l y SO2, than most h igher vege ta t ion , i t was decided t o monitor changes i n l i c h e n growth a s an e a r l y warning of t h e impact o f p o l l u t a n t s on a l l components o f t h e vege ta t ion .

I n 1976, Syncrude Canada Ltd. i n s t a l l e d a network o f 56 permanent p l o t s i n a r a d i a t i n g p a t t e r n centered on t h e 2 opera t ions and a t d i s t ances o f up t o 47 km. Within each p l o t 20, 200 cm perma-nent a u a d r a t s con ta in ina t h a l l i o f Parmelia s u l - -cats o r Hypogymnia physodes, 2 abundant bark- -l i c h e n s , were e s t a b l i s h e d and photographed. Most of t h e &adra t s were e s t a b l i s h e d o n w h i t e spruce (P icea e lauca . a 1 thouah a smal le r number wire e s t a b l i s h e d on' balsam f i r (Abies balsamea) and whi te b i r c h (Be tu la p a p y r i f e r a ) . ? photographs-were p ro jec ted an s u r f a c e a r e a s of s e l e c t e d l i c h e n t h a l l i were measured. I n 1979, a l l o f t h e quadra t s i n 12 s e l e c t e d p l o t s were rephotographed and t h e photographs analyzed a s before . The ob- j e c t i v e s o f t h i s p a r t i a l resurvey were ( a ) t o measure changes i n t h e s u r f a c e a r e a o f t h a l l i of P. s u l c a t a , t h e dominant l i c h e n s p e c i e s , i n t h e 3 year per iod 1976-1979, ( b ) t o t e s t t h e s i g n i f i - cance o f these changes a s a func t ion o f d i s t ance

P r e s e n t e d a t t h e Symposium on E f f e c t s of A i r P o l l u t a n t s on Mediterranean and Temperate Fores t Ecosystems, June 22-27, 1980, Rivers ide , C a l i f o r n i a , U.S.A.

~ n v i r o n m e n t a l i s t , Calgary Power L td . , Calgary, Alber ta , Canada, formerly, Research Associa te , LGL Ltd . , Environmental Research Associa tes , Edmonton, Alber ta , Canada; Head, T e r r e s t r i a l Environment Sec t ion and Research A s s i s t a n t , Environmental A f f a i r s Dept., Syncrude Canada Ltd. , Edmonton, Alber ta , Canada.

and/or d i r e c t i o n from t h e emission sources , and ( c ) t o a s s e s s t h e p r a c t i c a b i l i t y of t h e l i c h e n network a s a long term monitoring system f o r d e t e c t i n g a i r q u a l i t y impacts on vege ta t ion .

There was a s i g n i f i c a n t i n c r e a s e i n p ro jec ted t h a l l u s s u r f a c e a r e a i n 6 p l o t s , a s i g n i f i c a n t decrease i n 2 p l o t s , and no s i g n i f i c a n t change i n 4 p l o t s . I n most cases t h e n e t change i n l i c h e n s u r f a c e a r e a dur ing t h e 3 year per iod was l e s s than 10%. However, wi thin-plot v a r i a b i l i t y was very l a r g e wi th c o e f f i c i e n t s of v a r i a t i o n common- l y between 300-400%. The changes i n p ro jec ted t h a l l u s s u r f a c e a r e a were s i g n i f i c a n t l y but weakly, r e l a t e d t o d i s t ance ; t h e t h a l l i c l o s e s t t o t h e emission sources i n c r e a s i n g more i n a r e a than those a t a d i s t ance , where i n f a c t t h e r e was a n e t decrease i n s u r f a c e a r e a on t h e average.- F i e l d observat ions i n d i c a t e d t h a t t h e r e was no r e l a t i o n s h i p between l i c h e n c o l o r and/or v igor and d i s t a n c e and/or d i r e c t i o n from t h e emission source . It was evident i n a comparison o f t h e 1976 and 1 9 7 9 p a i r e d photographs t h a t t h e r e was a s i g n i f i c a n t l o s s o f whole t h a l l i and p o r t i o n s o f t h a l l i from most of t h e quadrats . It was n o t unusual f o r 10-20% o f t h e t h a l l i p resen t i n 1976 t o be miss ing i n 1979. This appeared t o be p r i - mari ly r e l a t e d t o t h e n a t u r a l process o f bark e x f o l i a t i o n , although animal a c t i v i t y and i n s e c t g raz ing a r e a l s o suspected causes .

This technique i s capable o f d e t e c t i n g s i g n i - f i c a n t changes i n t h e s u r f a c e a r e a of P. s u l c a t a t h a l l i over a 3 year per iod, however, i t r e q u i r e s c a r e f u l s t andard iza t ion and a l a r g e number o f samples due t o t h e l a r g e wi thin-plot v a r i a b i l i t y i n t h i s c h a r a c t e r i s t i c . The high v a r i a b i l i t y is r e l a t e d t o t h e r a t h e r non-uniform arowth o f t h e P. s u l c a t a t h a l l u s a s wel l a s t h e v a r i e t y o f n a t u r a l processes causing l o s s e s o f p o r t i o n s o f t h e t h a l l u s . Perhaps o t h e r a t t r i b u t e s o f t h e t h a l l u s would make b e t t e r i n d i c e s o f growth ( o r l ack o f growth), however, none were i n v e s t i g a t e d . The ex tens ive l o s s e s of whole t h a l l i r a i s e ques-t i o n s about t h e permanence o f t h i s system and hence its value a s a long term monitoring system. Because t h e predominant reason f o r t h a l l u s l o s s is bark e x f o l i a t i o n , t h i s problem is very much r e l a t e d t o t r e e spec ies . Spruce a r e p a r t i c u l a r l y bad i n t h i s regard. There was very l i t t l e t h a l l - u s l o s s from b i rch o r f i r . Notwithstanding t h e above d i f f i c u l t i e s , i t was concluded t h a t t h e r e was no a i r q u a l i t y caused damage t o P. s u l c a t a between 1976 and 1979 a s i n f e r r e d from t h e rela-t ionsh ips between t h e n e t change i n t h a l l i sur- f a c e a r e a and d i s t a n c e and/or d i r e c t i o n from t h e e m i s s i o n sources . This conclusion i s supported by f i e l d observat ions of l i c h e n co lo r and v i g o r . -

Acid Precipitation in California and Some Ecological Effects1

John G. McColl and Mary K. Firestone 2

Wet and d r y p r e c i p i t a t i o n s were monitored on an event bas is i n 1978-9 a t Berkeley and San Jose ( p o l l u t i o n source areas i n the San Francisco Bay area) , Davis and Par1 i e r ( i n the cen t ra l a g r i c u l -t u r a l and rangelands) , Chal lenqe ( lower S ie r ran f o r e s t ) , and Tahoe C i t y (on t he shore o f Lake Tahoe) . Concentrations o f t h i r t e e n i o n i c species and s p e c i f i c conductance and volume were measured (Table 1 ) .

Ac id r a i n (pH < 5.6) was common a t a l l e i g h t s i t e s . Mean pH o f storms var ied from 4.24 a t San Jose t o 5.20 a t Davis, and the lowest pH o f any storm was 3.71 a t San Jose. The pr imary cause o f the a c i d i t y was probably the a i r p o l l u t a n t NOxy f o l l o w i n g i t s d i s s o l u t i o n i n wet p r e c i p i t a t i o n . NO? was t he anion most c l o s e l y co r re l a t ed w i t h H', and NO3 genera l l y occurred i n greater concen-t r a t i o n than SO$-.

Tota l d r y deposi t ions o f chemical cons t i tuen ts between rainstorms were o f the same order as t o t a l wet deposi t ions du r i ng storms. Dry deposi t ion dur inq summer would g r e a t l y increase the amounts recorded i n t h i s study which was conducted i n the wet season on ly . However, more research i s needed i n procedures f o r quan t i f y i ng d r y atmospheric deposi t ion.

' A1 though NOS concentrat ion (pg/1) and a c i d i t y (H" concentrat ion, p g / l ) of wet p r e c i p i t a t i o n were g rea tes t i n p o l l u t i o n source areas, t o t a l depo-s i t i o n (kg lha) o f NO3 and H+ were g rea tes t i n the non-urban recep to r areas o f Napa and Chal lenqe; t h i s was l a r g e l y a f unc t i on o f t he g rea te r p rec i - p i t a t i o n volumes a t these two s i t e s (Table 1 ) . Thus eco log ica l e f f e c t s may be expected i n the coast ranges and S ie r ras w i t h i n the genera l east- to-west "wash-out fan" o f wet p r e c i p i t a t i o n , as we l l as w i t h i n p o l l ut ion-source areas.

E f f ec t s o f these ac i d inpu ts t o C a l i f o r n i a s o i l s are c u r r e n t l y be ing assessed. These inves- t i g a t i o n s on s o i l e f fects inc lude research on both the inorganic phase o f s o i l and on the o rqan ic l - b i o l oq ica l components.

p r e s e n t e d a t t he Symposium on Effects of A i r Po l l u t an t s on Mediterranean and Temperate Forest Ecosystems, June 22-27, 1980, Rivers ide, Ca l i fo rn ia , U.S.A.

~ s s o c i a t e Professor of S o i l Science and Associate S p e c i a l i s t i n So i l Microbiology, respec t i ve ly , Un i ve r s i t y o f Ca l i f o rn i a , Berkeley, Ca l i f o rn i a , U.S.A.

Table 1 --Mean i o n i c concentrat ions o f wet p rec i p i -t a t i o n dur ing the study per iod i n 1978-9 (peqI1).

H' (Lab.) 22.1 6.8 10.9 13.0 38.0 7.9 6.3 14.6 ~ a + 36.9 11.8 15.3 12.8 33.1 14.5 15.1 22.0 K+ 1.5 0.6 1.4 2.1 1.5 1.1 1.1 1.4 ~ a 2 + 6.0 4.3 8.0 10.9 12.6 3.3 5.6 4.6 kJ2+ 9.6 1.7 3.6 7.0 9.7 3.8 5.7 5.3 ~e3+ 0.3 0.0 0.6 0.4 0.8 0.2 0.4 0.4 ~n2+ 0.1 0.0 0.1 0.6 3.1 0.1 0.1 0.1 cu2+ 0.1 0.1 0.1 0.2 0.3 0.1 0.2 0.7 zn2+ 0.3 0.1 0.2 0.2 0.6 0.1 0.1 0.2

NH; 8.0 4.1 40.0 11.9 19.1 9.7 35.5 12.1

NO;C l -

13.7 40.1

6.7 3.7

43.4 11.2

19.9 7.7

16.4 38.9

11.1 14.2

22.6 16.4 14.0 -23.1

SO:- 10.2 13.3 13.8 8.6 10.0 6.2 19.0 11 .7

Cond . (pmho/cm) pH (Lab.)

13.9 4.7

.3.9 5.2

17.4 4.7

10.6 4.9

16.2 4.4

6.4 5.1

9.6 5.2

10.7 4.8

Vol. (cm) 52.7 78.0 19.7 110.7 21.0 64.9 39.7 62.0

'BE Berkeley, TC Tahoe C i t y , KE Kearny ( f i e l d s t a t i o n a t par1 ier) , CH Challenge, SJ San Jose, HO Hop1 and, DA Davis , and NA Napa .

I n the inorganic s o i l -chemical s tud ies, s o i l s cover ing a wide range o f parent mate r ia l s and age are be ina t rea ted w i t h ac i d inputs , and the subsequent leaching pat terns o f ions ( i n c l ud i ng ~ l + 3 , H+, Nat, K+, Mg++, Ca^) are be ing determined.

The b i o l o g i c a l i n ves t i ga t i ons inc lude assessment o f poss ib le e f f e c t s on the s o i l - p l a n t n u t r i e n t system. The f i r s t 10-week p o t - t r i a l , using a Yolo se r ies s o i l and qrowina ba r l ey and c lover , has j u s t been completed. Prel iminary r e s u l t s i nd i ca te marked qrowth increases i n t r e a t - ments where the p lan ts were sprayed w i t h so lu t ions o f pH 2.0 and 3.0. This r e s u l t i s a t t r i b u t e d t o greater add i t i ons o f SO^- and NO?, and/or t o increased ava i l a b i l it y of s o i l n u t r i e n t s i n these lower-pH treatments. However, spo t t i ng o r leaves by ac i d d rop le ts a lso occurred i n the pH 2.0 treatments. N i t r i f i c a t i o n , deni t r i f i c a t i o n and n i t rogen f i x a t i o n a c t i v i t i e s are be ing measured i n both the rhizosphere and non-rhi zosphere s o i l .

Leaf Litter Decomposition in the Vicinity of a Zinc Refinery

Emmissions from a large zinc refinery in north- ern Ontario have been monitored for 10 years and an accumulation of zinc, copper, cadmium, arsenic and lead in the soil and vegetation surrounding the refinery complex has been documented. It was considered that decomposition of leaf litter as a part of the nutrient cycling process might be a convenient method to monitor the initial impact of these metals on the environment. This investigation was undertaken in the fall of 1977. Ny-lon mesh bags containing 10 q (oven-dry weight) of trembling aspen (Populus tremuloides) were set out at several locations around the refinery. Two sources of aspen foliage were utilized inclu- ding foliage from a control location and contaminated foliage collected near the refinery. The exposure locations for the litter bags included three sites in close proximity to the refinery, (Plot A, B, C) one site 2.2 km from the refinery (Plot D) and one at a control location (80 km southwest of the refinery) (Plot E) .

The litter bags were allowed to over-winter and triplicate bags of each litter type were collected in May, June and August of 1978 and in May, July and August in 1979. Microarthropods were extracted from the bags in modified Tulgren funnels in the laboratory. The litter was then dried to determine the leaf weight loss and processed for chemical analysis.


plant Pathologist, Ministry of the Environment, 199 Larch Street, Sudbury, Ontario, P3E 5P9.

It was found that the rate of decomposition of the leaf litter was lower at sites nearest to the refinery and that contaminated foliage de- composed more slowly than control foliage at all sites. The microarthropod population was dominated by mites and springtails. The number of microarthropods was generally lower at the sites nearest to the refinery and was also lower in the litter baqs containing the contaminated foliage. The numbers of microarthropods appeared to fluc- tuate with moisture content of the litter. It was found that the concentrations of zinc, copper, cadmium, lead, arsenic, iron, sulphur and sele- nium in the leaf litter increased with time at the sites nearest to the zinc refinery but only a slight increase was noted at the more distant sites.

z PLOT NO - A' I-

60" CONTAMINATED LITTER ..*-*. m CONTROL LITTER -g 45-0 a

30-I-

;z 15-u n

NOV MAY JUN AUG MAY JUL AUG 1977 1978 1979

Figure 1. Pattern of decomposition of two types of leaf litter at two sites.

NOV MAY JUN AUG MAY JUL AUG 1977 1978 1979

Figure 2. Zinc accumulation is typical of metal accumulation in leaf litter.

Effects of Chronic Air Pollution Stress on Allocation of Photosynthate by White Pine

S. B. McLaughlin, R. K. McConathy, and D. Duvick2

A1 location of ^c-photosynthate by in s i tu branches of nine field-grown white pine trees was studied to determine whether distribution patterns differed between trees with apparent differences in sensi t iv i ty to a i r pollution stress. Three trees were selected in each of three sensit ivity classes which were differentiated on the basis of needle length, mottling, and duration of reten-tion. Previous studies (Mann e t a1. 1980) indicated that photosynthetic potential of foliage from trees in these three classes was not significantly different. Growth ring analysis of increment cores indicated that average annual increment of intermediate and sensitive trees was 98% and 47%, respectively, of that attained by the tolerant trees (7.8 mm y r - l ) over the past 18 years (Fig. 1 ). Sensitive trees showed a marked decline in annual growth during the past 10 years.

Foliage was labelled with ^COz four times during the growing season (June, July, August and November). Of the paired branches from each tree labelled on each date, one was harvested a f te r seven days and the remainder in November a t the end of the growing season. Photosynthate allocation patterns were compared by determining levels of f o l i a r retention and allocation to nearby branches. In June when elongating needles were approximately 50% of their final length, ^ C movement patterns in needles of three age classes (Fig. 2 ) indicated that contribution of ^C-photosynthate by old needles to new needle growth was occurring. This process was most rapid in tolerant trees which retained needles from two prior years and leas t significant in sensi t jve trees. Lower levels of incorporation of photosynthate into fo l i a r tissues occurred subsequently (X = 35% in June, 27% in July, and 5% in August a f t e r seven days). There were no dis t inct differences in f o l i a r retention of 1 4 C between the three sensi t iv i ty classes which could be associated w i t h the distribution of high levels of ozone (1h avg > 0.08 ppm) near the study area. ~ i g n if ican t 2-year-old needle retention on tolerant trees did not extend beyond July.

Presented a t the Symposium on Effects of Air Pollutants on Mediterranean and Temperate Forest Ecosystems, June 22-27, 1980, Riverside, California, U.S.A.

%search Staff llember, Research Associate, and Technician, respectively, Terrestrial Ecology Section, Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, U.S.A.

Generally higher levels of transfer of 14c from foliacje into branches were noted in the tolerant trees throughout the growin season. Higher levels of trans1 ocation of ^C-photosynthate out of 1 -year-01 d need1 es than current-year needles were also found for a l l sensit ivity classes. Enhanced current needle elongation (+25% sensi- t ive, +lo% intermediate, and +3% tolerant) compared to the previous year was associated with lower than average ozone levels and higher than average rainfall during the growing season. Data support the hypothesis that growth limitations in sensitive trees are a function of stress-induced reductions in photosynthate availabil i ty which result from reduced needle length (a function of decreased availabil i ty of carbohydrates for needle growth) and premature needle senes-cence. The resulting chronic decline of sensitive trees i s likely a result of interactions between a i r pollution stress and s i t e factors which may include secondary belowground pathogens.

Acknowledgments: Research sponsored by the U . S. Environmental Protection Agency under Inter- agency AgreementNo. 40-740-78 and the U.S. Department of Energy under Contract W-7405-eng-26 with Union Carbide Corporation.

Literature Cited

Mann, L. K., S. B. McLaughlin, and D. S. Shri ner. 1980. Seasonal physiological responses of white

pine under chronic a i r pollution stress. Env. Exp. Bot. (in press).

240 1

1960'62 'â‚ '66 '68 '70 '72 '74 '76 '78 1980 0 24

YEAR TIRE SINCE LABtLLIHt (m)

F i g u r e I ( l e f t ) - - A v e r a g e annual d iameter growth o f 3 t r e e s i n each o f 3 s e n s i t i v i t y c l asses .

F i g u r e 2 ( r i g h t ) - - D i s t r i b u t i o n o f ^C pho tosyn tha te i n f o l i a g e 0, I , and 7 days a f t e r ^cog uptake i n June.

168

Effects of SO2 and Ozone on Photosynthesis and Leaf Growth in Hybrid Poplar

Reginald D. Noble and

Keith F. ~ e n s e n 2

Plants i n the na tura l environment a re often si-multaneously exposed t o a combination of many atmospheric pol lu tan ts . Thus it is of i n t e r e s t t o as-ce r t a in the nature of in te rac t ion of these pollu- t a n t s on p lan t development and metabolism. Two pol- l u t an t s commonly encountered i n the atmosphere which a r e pa r t i cu l a r ly tox ic t o p l an t s and would appear t o o f f e r po t en t i a l f o r in te rac t ion a r e SO2 and 03.

METHODS

Plants of hybrid poplar #207 (Populus del toides Bartr. X P. trichocarpa Torr. & Gray) were grown from cut t ings under greenhouse conditions. Six week old p l an t s were fumigated i n control led environment chambers f o r 12 hours per day f o r 24 con-secut ive days. Four s e t s of p lan ts were used a s follows : Set 1-Controls (no fumigation) ; Set 2-Fu- migated with SO2 a t 0.5 ppm; Set 3-Fumigated with 03 a t 0.25 ppm; Set 4-Fumigated with SO2 a t 0.5 pprn p lus O3 a t 0.25 ppm. A t the end of the 24-day fumigation period, number of leaves per p l an t , l eaf f resh and dry weight and leaf area were determined. During the l a t e r s tages of the fumigation, photosyn- t h e s i s measurements were determined f o r s ing le a t - tached leaves from p lan t s fumigated with SO2 and those fumigated with s02+03. Photosynthetic mea-surements were made a t ambient C02 leve ls (300 pprn C02) and a t 1000 pprn C02.

RESULTS

Plants fumigated with SO2 showed l i t t l e v i s ib l e evidence of in jury while those fumigated with O3 o r a combination of the two began t o develop t i n y ne- c r o t i c spots a f t e r 5 t o 7 days of exposure. Soon a f t e r lower leaves began t o abscise and by 14 days extensive in jury was apparent on leaves below the 7th node from the apex. Both O3 and S02+03 t r ea t - ments caused a reduction i n the number of leaves per p lan t ; however, the r a t e of leaf formation was not affected f o r the four groups. The number of leaves per p l an t was lower i n the O3 treatment group than i n the S02+03 group, suggesting an antagonist ic

_L Presented a t the Symposium on Effects of A i r

Po l lu tan ts on Mediterranean and Temperate Forest Ecosystems, June 22-27, 1980, Riverside, Cal ifornia, U.S.A.

p r o f e s s o r of Biological Sciences, Bowling Green S t a t e University, Bowling Green, Ohio; Research Sc i en t i s t , U.S. Department of Agriculture, Forest Service, Delaware, Ohio.

relat ionship. Fumigation tended t o cause a decrease i n leaf area, l eaf dry weight and leaf f r e sh weight. This was increasingly t rue a s the dis tance from the p lan t apex increased. Pol lutant in te rac t ion eval- uations revealed an antagonist ic re la t ionship between the responses t o O3 and SO2. Ozone which re-tarded growth most had l i t t l e o r no e f f e c t on a rea , dry o r f resh weight of leaves above node 5; however, these parameters were reduced by 25 t o 40 percent i n leaves fumigated with O3 a t node 9. These and re la ted observations demonstrate t h a t O3 r e t a rds growth of leaves i n t h i s p lan t only during the l a t - e r stages of t h e i r development. Ozone fumigated leaves with v i s i b l e in jury comparable t o those fumigated with both SO2 and O3 contained l e s s dry matter per un i t area.

Photosynthetic measurements on controls a s w e l l a s p lan ts fumigated with SO2 and S02+03 revealed

l i t t l e difference i n r a t e of C02 assimilat ion a t 300 pprn COT Even i n leaves of S02+03 fumigated p lan ts where v i s ib l e in jury was extensive the photosynthetic r a t e was reduced by only 10 t o 20 percent. When the C02 concentration was elevated t o 1000 pprn C02 photosynthetic r a t e s f o r cont ro ls , SO2 fumigated and S02+03 fumigated leaves (with no v i s i b l e injury) were elevated three-fold t o approximately 35 mg C02 dm'-hr-l. In leaves i n which in jury was apparent the photosynthetic r a t e increas-e s were usual ly l e s s than two-fold, t o a l eve l of approximately 18 mg C02 dm-2hr-1 (whether the injury was severe or barely discernable).

DISCUSSION

Ozone, and O3 i n combination with SO2 hasten senescence and promote r a t e of leaf drop t o the ex ten t t h a t control p lan ts have approximately 50 percent more leaves than fumigated ones. Fumiga-t i on with SO2 causes no such e f f ec t . Analysis of attached leaves f o r treatment e f f e c t s c l ea r ly shows an O3 e f f e c t but l i t t l e o r no SO2 e f f ec t . In com-bination these pol lu tan ts a t t h i s concentration in t e r ac t i n an antagonist ic manner i n r e l a t i on t o growth parameters.

Measurements of e f f e c t s of fumigation on photosynthesis indicate t h a t leaf photosynthesis i s not d ra s t i ca l l y reduced even i n the presence of con-siderable injury. It appears t h a t in jury tends t o reduce leaf po t en t i a l t o respond t o enhance- ment conditions more so than the a b i l i t y t o f i x C02 under conditions where C02 may be l imit ing.

Behavior of Airborne Fluorides in Soils'

Janina Polomski, Hannes Flfihler, and Peter laserâ

Accumulation of airborne f luor ides i n s o i l s i s sa id t o be a s ide e f f e c t of minor importance i f it i s compared w i t h the phytotoxici ty of man-made gaseous f luoride. When s o i l f luor ide was consid-ered i n t he pas t , F-uptake of p lan ts , l e a f in jury o r y i e ld reduction was of prime concern. Not much i s known about the f a t e of F-pollutants a f t e r being deposited onto the s o i l surface o r incorporated i n the p l an t l i t t e r layer . Our study aims a t providing experimental t oo l s and data fo r a b e t t e r understanding of long-termed e f f ec t s . The object ive is t o pin down the most s ign i f i can t , cont ro l l ing mechanisms of the F-mobility i n s o i l s .

Field experiments: In t he v i c in i ty of a 30000 t Aluminum smelter, b u i l t 1908, we ob-served t h a t F ac tua l ly accumulates i n the s o i l (Table). The s o i l s sampled a t various d is - tances d i f f e r i n many respect but a r e a l l calcareous. The F-contents do depend upon distance from the emission source.

distance from total F watersoluble F dissolved F F-content of Al-smelter 1 %-year old

(pg F per ml pine needles (km) 1 (pg F per gram soil) soil solution) ( P P ~

In s o i l s , f luor ide coexists i n many d i f f e r en t forms which makes the t o t a l F-content t o be a hardly in te rpre tab le s o i l cha rac t e r i s t i c s .

In a pine stand, located 1.8 km from the smelter t h e magnitude of the annual F-input and leaching losses were determined (kg F per y and ha) : 1-3 kg within dead p l an t mater ia l , 6-10 kg atmospheric washout, 40-80 kg adsorption and sedimentation. The leaching losses out of the root zone were estimated t o be some 80-100 kg.

Under pine canopies the F-contents i n the surface layer (humus) a r e systematical ly higher than i n the subsoi l (mineral horizon) whereas i n uncult ivated open land under grass cover f luor ide accumulates i n the subsoi l .

p r e s e n t e d a t the Symposium on Effec ts of A i r Po l lu tan ts on Mediterranean and Temperate Forest Ecosystems, June 22-27, 1980, Riverside, Cal ifornia, U.S.A.

~ g r o n o m i s t , s o i l phys ic i s t and chemist, respect ively, Swiss Forestry Research I n s t i t u t e , Binnensdorf, Switzerland.

Laboratory experiments : What controls the f luor ide t ranspor t i n s o i l s ? In case of a non-calcareous s o i l (pH 5.2) the amount of f luor ide adsorbed within a mixture of s o i l and NaF- solut ion being equi l ibra ted on a shaker (3340 \lg ~ / g ) s o i l equals approximately the F-adsorption i n the course of a percolat ion through a s o i l s l ab (Fig.)

Breakthrough-Curves of S i b Clay Soil with and without CaCO,

Cumulated Outflow [Number of Pore Voluminal

The close agreement between the two experiments ind ica tes t h a t adsorption and prec ip i ta - t i on a r e f a s t react ions as compared with the veloci ty of the percolat ing s o i l solut ion. In calcareous s o i l s , however, the exchange k ine t i c s between the l i qu id and so l id phase controls t he extent of accumulation and depletion. The exchange proceeds too slow t o keep up with the pace of the moving water. This explains the amazingly high F-mobility observed i n case of the F-contaminated calcareous s o i l s .

In the course of the percolat ion experiments the leachates from the s o i l columns contain appreciable amounts of so lubi l ized organic matter and aluminum. For a given s o i l type the leaching losses depend i n the f i r s t place upon the F-content of the i n f i l - t r a t i n g solut ion and fur ther upon s o i l type and the F-compounds used t o make up the percolat ing solut ion. Under f i e l d conditions with 8-10 ppm F i n the s o i l so lu t ion such phenomena may a l s o occur. A s i gn i f i can t amount of soluble organic material can be l o s t which may represent an energy subs t ra te shortage fo r the microorganisms, and furthermore t he Al-concentrations possibly reach phytotoxic leve ls . A t t h i s point the experimental evidence r a the r backs up questions than pro- vides d e f i n i t e answers.

Multiple Pollutant Fumigations Under Near Ambient Environmental Conditions Using a Linear Gradient Technique1

2P.B. Reich, R.G. Amundson, and J.P. Lassoie

I n v e s t i g a t i o n s of t h e impact of atmospheric p o l l u t a n t s on p l a n t s normally involve a r t i f i c i a l - l y r a i s i n g t h e concen t ra t ion of c e r t a i n gases a- round s tudy p l a n t s . Such experiments t y p i c a l l y u t i l i z e enc losures which g r e a t l y modify o t h e r environmental f a c t o r s . Hence, t h e s e experiments may no t a c c u r a t e l y t e s t p l a n t responses under ambient cond i t ions . The development of open-top, f i e l d fumigat ion chambers (Mandl and o t h e r s 1973) and a new l i n e a r g rad ien t exposure system (Shinn and o t h e r s 1977) have been a t t empts t o s o l v e t h i s problem.

I n 1979 we cons t ruc ted a modified l i n e a r gra- d i e n t system and 6 open-top chambers. The gra- d i e n t system enabled t h e simultaneous exposure of numerous s tudy p l a n t s t o a concen t ra t ion g rad ien t of SO2 and 03. S ince t h e system does n o t use enc losures , p l a n t s a r e e a s i l y accessed and ex-pe r i ence near-ambient environmental cond i t ions . A p l o t of soybeans (Glycine s.v a r . Hark) i n I t h a c a , NY was used i n an a t tempt t o answer t h e fol lowing ques t ions .

1 ) Can t h e g rad ien t system be used t o expose p l a n t s i n t h e f i e l d t o c o n t r o l l e d l e v e l s of a i r p o l l u t a n t s wi thout s i g n i f i c a n t l y a l t e r i n g t h e i r environments?

2) Is p l a n t growth s i g n i f i c a n t l y d i f f e r e n t i n open-top chambers ve r sus i n a l i n e a r g rad ien t system?

3) What r educ t ions i n soybean seed y i e l d w i l l r e s u l t from exposure t o moderate l e v e l s of SO2 and 03 dur ing t h e seed maturat ion pe r iod?

During t h e seed maturat ion pe r iod , t h e p l a n t s were exposed t o SO2 and O3 f o r about 55 h over a 20-day per iod. On a l l occas ions , a l i n e a r con-c e n t r a t i o n g r a d i e n t was c r e a t e d by the system. Mean concen t ra t ions of SO2 and O3 a t t h e "high" end of t h e g r a d i e n t were 0.16 and 0.06 ppm, re-s p e c t i v e l y , whi l e ambient concen t ra t ions of both p o l l u t a n t s were about 0.02 ppm. Maximum hour ly means a t t h e "high" end of t h e g rad ien t were0.50 and 0.17 ppm SO2and 03, r e s p e c t i v e l y . By moni- t o r i n g t h e p l o t i n a g r i d des ign, we were a b l e t o account f o r t h e e f f e c t s of wind on p o l l u t a n t l e v e l s . I n t h e open-top chambers, p l a n t s were

p r e s e n t e d a t t h e Symposium on E f f e c t s of A i r P o l l u t a n t s on Mediterranean and Temperate Fores t Ecosystems, June 22-27, 1980, R ive r s ide , C a l i f o r n i a , U.S.A.

~ r a d u a t e s tuden t of Fores t Science, Cornel l Unive r s i ty , I t h a c a , NY; Post Doctoral Associa te , Boyce Thompson I n s t i t u t e , I t h a c a , NY; and A s s i s -t a n t P ro fessor of Fores t Science, Cornel l Unive r s i ty , I t h a c a , NY.

exposed t o 0.30, 0.10, and 0.02 (ambient) ppm SO2 f o r 72 h , over a 30-day pe r iod , dur ing t h e pod- f i l l i n g s t age .

Comparisons of t r ea tment s revealed t h a t t h e g rad ien t fumigations reduced t o t a l bean y i e l d pe r p l a n t and d ry mass per bean by a s much a s 39 and 14 pe rcen t , r e s p e c t i v e l y . I n t h e open-top cham-b e r s , t o t a l bean y i e l d per p l a n t and dry mass per bean were reduced by a s much a s 10 and 7 pe rcen t , r e s p e c t i v e l y . It i s of i n t e r e s t t o n o t e t h a t both t h e "high" and "medium" (mean SO2-0.09 ppm, mean 03-0.04 ppm) t reatments i n t h e g r a d i e n t system caused much g r e a t e r r educ t ions i n y i e l d than did t h e 0.30 ppm SO2 t reatment i n t h e open-top chamber. I n i n t e r p r e t i n g these d a t a , one must remember t h a t t h e p l a n t s i n t h e g rad ien t system did exper ience short-term peaks much h igher than t h e i r mean concen t ra t ion exposures.

I n any case , 03, a l though p resen t a t moderate- l y low l e v e l s , was (a lone o r s y n e r g i s t i c a l l y w i t h SO2) probably respons ib le f o r t h e g r e a t e s t r e -duc t ions i n seed s i z e and y i e l d .

I n open-topchambers, one can a c c u r a t e l y con-t r o l p o l l u t a n t l e v e l s . I n c o n t r a s t , t h e l i n e a r g rad ien t system al lows fumigat ions which va ry wi th time and wind, a s under ambient cond i t ions . The l i n e a r g rad ien t system proved t o be an e f -f e c t i v e means of fumigating p l a n t s w i t h m u l t i p l e p o l l u t a n t s under ambient environmental condi- t i o n s . Another modi f i ca t ion of t h e g rad ien t sys-tem i s c u r r e n t l y underway s o a s t o a l low f o r a n a l y s i s of t h e i n t e r a c t i o n s between SO2 and 03, and the e f f e c t s of such on va r ious hardwood t r e e seed l ings .

This s tudy was supported i n p a r t by t h e North- e a s t e r n F o r e s t Experiment S t a t i o n , F o r e s t Se rv ice , U.S. Department of Agr icu l tu re , through t h e Con- sor t ium f o r Environmental F o r e s t r y S tud ies (For-e s t Se rv ice Grant 23-169) and by t h e Cornel l Unive r s i ty A g r i c u l t u r a l Experiment S t a t i o n (McIntire-Stennis P r o j e c t NY(C)-147556).

LITERATURE CITED

Nandl, R.H. , L.H. Weinstein, D.C. McCune, and M. Keveny . 1973. A c y l i n d r i c a l , open-top chamber f o r t h e

exposure of p l a n t s t o a i r p o l l u t a n t s i n t h e f i e l d . J. Environ. Qual. 2:371-376.

Shinn, J . H . , B.R. Clegg, and I1.L. S t u a r t . 1977. A l inea r -g rad ien t chamber f o r exposing

f i e l d p l a n t s t o cons tan t l e v e l s of a i r p o l l u t a n t s . DOE-Preprint UCKL-80411.

Changes in Plant Communities with Distance from an SO2 Source

Paul R. scale2

Investigations were carried out to assess the effects on plant community composition of sulphur dioxide (SO2) emitted from an iron sintering plant in Wawa, Ontario, Canada. Diversity indices and the ordination techniques of Correspondence Analysis (C.A.) and Principal Component Analysis (P.C.A.) were used to discern community level changes. Of special interest were the subtle changes in areas noted to be only slightly affected by SO2 emissions. Over 60 upland birch stands were accessed along a north-easterly transect away from the source at distances of 12 to 55 km. Species specific data was collected on the tree, shrub and ground flora.

Changes in species composition are dramatic as the 30 year SO2 source is approached. The total percent cover of the dominant, predominantly boreal, ground flora species are shown in Figure 1. They reflect the complex pattern of species abundance which occurs along the transect. Characteristic is the transitory increase in abundance which occurs in most species. What is particularly evident is the ability of many species to take advantage of the increasing damage caused first to the tree canopy and subsequently to the shrub layer. This

Figure 1--Changes in ground flora species abundance with distance using a running average of percent cover: Am, Aster macrophyllus; An, Aralia nudicaulis; Df, Deschampsia flexuosa; Dl, Diervilla lonicera; Me, Maianthemum canadense; Va, Vaccinium angustifolium.


~raduate Student, Institute for Environmental Studies, University of Toronto, Toronto, Ontario, Canada.

occurs despite their own greater exposure to S O . The low-bush blueberry (Vaccinium angustifoliumL Ait.) for example, becomes very abundant at distances of 20 to 30 tan yet shows considerable SO2 damage in that area. The first substantial change in species abundance occurs at a distance of 40 km where beaked hazel (Corylus cornuta Marsh.) becomes very abundant before a very rapid decline. This undoubtedly contributes to the drop in the abundance of the large leaved aster (Aster macrophyllus L.) at that distance.

Dealing collectively with all species of a community to discern changes caused by a pollutant is, for theoretical reasons and from experience, a more satisfactory approach than changes in indivi- dual species abundance. Diversity indices have been used extensively for this purpose. However, the data from Wawa indicates that although diversity indices can deal with spatial/structural changes in the community, they do not adequately reflect the subtler changes in species composition. Ordination techniques, such as C.A. and P.C.A., are better suited for this purpose. For example, the Shannon-Weiner Diversity index has a transitory increase between 20 and 30 km before declining at distances below 20 km. In contrast, the first axis of C.A. using ground flora data shows a simple, linear change from 12 to 33 km (Figure 2). C.A. is most effective in reflecting overall trends whereas P.C.A. is particularly useful in discerning differences in stands of very similar composition. On the basis of P.C.A. using shrub density data, the separation of sites in intermediate areas from controls can be achieved. The boundary between the two groups in Figure 2 corresponds well with the line designated in 1973 and 1974 as separating areas which do and do not show visible leaf damage.

Figure 2~Distance vs Axis 1 of ground flora (percent cover) and shrub density (number of stems under 5 cm diameter at breast height) data using C.A. and P.C.A., respectively.

Lichens as Ecological Indicators of Photochemical Oxidant Air Pollution1

Lorene L. S i g a l and Thomas H. Nash 111~

From t h e l a t e 1960 's t o t h e p resen t , both t h e concentrat ion and dose of photochemical oxidant a i r p o l l u t a n t s (ozone and peroxyacetyl n i t r a t e o r PAN) have continued t o inc rease i n t h e mountainous a r e a s surrounding t h e Los Angeles Basin. Since 1972, a mul t i -d i sc ip l ina ry team of e c o l o g i s t s has monitored and analyzed t h e eco log ica l consequences of t h i s p o l l u t i o n i n t h e con i fe r f o r e s t ecosystem of t h e San Bernardino Mountains. Our l i c h e n study paral-l e l s and expands t h e parameters of t h e aforemen-t ioned s tudy and al lows a comparison of t h e r e l -a t i v e s e n s i t i v i t y of l i chens versus higher p l a n t s t o oxidants .

H i s t o r i c a l l y , l i chens have been demonstrated t o be s e n s i t i v e i n d i c a t o r s of a i r p o l l u t a n t s such a s s u l f u r dioxide. More recen t ly , t h e r e i s s t rong evidence t h a t l i c h e n s a r e a l s o s e n s i t i v e t o hy-drogen f l u o r i d e and heavy metals . The present s tudy documents f o r t h e f i r s t time t h a t l i c h e n s a r e a l s o s e n s i t i v e t o ozone and peroxyacetyl n i t r a t e .

F i e l d i n v e s t i g a t i o n s were conducted i n four mountain ranges surrounding t h e Los Angeles Basin. A f i f t h s i t e i n Cuyamaca Rancho S t a t e Park, e a s t of San Diego, was chosen a s t h e con t ro l a rea . Resul ts of sampling l i c h e n s on Quercus k e l l o g g i i Newb. and c o n i f e r s showed o v e r a l l spec ies r i chness decreased by 38 percent i n t h e highly impacted San Bernardino Mountains. Cover va lues f o r spec ies on Q. kellog-

decreased by 16 percen t ; f o r l i chens on con-i f e r s t h e decrease was 78 percent . The l a t t e r de-crease i s l a r g e due to t h e f a c t t h a t the "sen-s i t i v e " f r u t i c o s e l i c h e n spec ies a r e found mainly on c o n i f e r s . There was an inverse r e l a t i o n s h i p between t h e cover of l i chens a t b r e a s t height on c o n i f e r s and t h e oxidant dose es t imates a t s i t e s i n t h e San Bernardino Mountains ( f i g . 1 ) . A threshold is seen a t 180 ppm-hrs above which t h e l i chens a r e almost absent .

Fumigation s t u d i e s i n t h e l abora to ry provided a d e f i n i t i v e way of t e s t i n g t h e response of f i e l d s e n s i t i v e and f i e l d t o l e r a n t spec ies t o con t ro l l ed concen t ra t ions of ozone and PAN s i m i l a r t o those

p r e s e n t e d a t t h e Symposium on E f f e c t s of A i r P o l l u t a n t s on Mediterranean and Temperate Forest Ecosystems, June 22-27, 1980, Rivers ide, C a l i f o r n i a , U.S.A.

2 Research Associate , Oak Ridge National Lab-

o r a t o r y , Environmental Sciences Division, P.O. Box X, Oak Ridge, Tenn. 37830. Operated by Union Carbide Corporation under con t rac t W-7405-eng-26 with t h e U.S. Department of Energy; and Associate Professor of Ecology and Lichenology, Arizona S t a t e Univers i ty , Tempe, Ariz. 85281.

occurr ing i n t h e f i e l d . In ju ry was documented a s a s i g n i f i c a n t reduct ion i n g ross photosynthesis. Parmelia s u l c a t a Tayl. exh ib i ted g r e a t e r s e n s i t i v -i t y t o ozone and PAN than Hypogymnia enteromorpha (Ach.) Nyl. These r e s u l t s were c o n s i s t e n t wi th f i e l d observat ions .

A s a r e s u l t of c o l l e c t i o n s made by H. E . Hasse and t h e subsequent pub l ica t ion of h i s "Lichen F lora of Southern Cal i fornia" i n 1913, t h e present d i s t r i b u t i o n and v i t a l i t y of a number of l i c h e n s was compared t o t h e i r d i s t r i b u t i o n a t t h e t u r n of the century. There was a 50 percent decrease i n spec ies r ichness . I n add i t ion , marked morpho-l o g i c a l d e t e r i o r a t i o n was seen i n t h e t h a l l i of e x i s t i n g f o l o s e spec ies such a s Hypogymnia enter-omorpha. Forty-two percent of t h e t h a l l i c o l l e c t e d i n t h e San Bernardinos were bleached and 44 percent were convoluted i n c o n t r a s t t o no bleaching o r con-volut ion i n c o l l e c t i o n s made i n t h e Cuymacas. Thal lus dimensions were decreased by approximately 50 percent i n t h e San Bernardino c o l l e c t i o n s .

The importance of l i chen s t u d i e s l i e s i n t h e i r s e n s i t i v i t y t o a i r p o l l u t i o n and t h e i r p o t e n t i a l use a s bioind-icators . By monitoring t h e abundance and d i s t r i b u t i o n of s e n s i t i v e l i c h e n s , i t i s pos-s i b l e t o e s t i n a t e the magnitude of a i r po l lu t ion . use of l i chens i n t h i s mat ter may be f e a s i b l e no t only a s c u r r e n t l y appl ied i n nor thern Europe with s u l f u r dioxide a i r p o l l u t i o n , bu t a l s o over l a r g e geographical a r e a s impacted by photochemical oxidant a i r po l lu t ion .

Acknowledgment: This s tudy was supported by National Science Foundation Grant DEB-7610244 t o D r . Thomas H. Nash 111, Dept. of Botany/Micro-biology, Arizona S t a t e Univers i ty , Tempe, Arizona 85281.

- ORNL- DWG 80 - 7556 ESD f 3 0 0 I i r r 1

Figure 1--Percent l i n e a r cover a t b r e a s t he igh t of Le thar ia vulpina (1.) Hue and Hypop-ymnia enteromorpha (Ach.) Nyl. a s a func t ion of t h e oxidant dose es t imates (ppm - h r s . = t h e mean oxidant concentrat ion i n ppm mul t ip l i ed by t h e time of exposure) a t s i t e s i n t h e San Bernardino Mountains.

Y p 2 2 0 'nw

w in 180 0n

1 4 0

0 1 0 0

-CAMP PAIVIKA - -

BARTON FLATS -

SKY FOREST ,GREEN VALLEY CREEK - -

DEERLICK^ 1 O f 2 3 4 5 6 7 1. COVER OF LETHARIA VULPINA AND

HYPOGYMNIA ENTEROMORPHA

The Effects of Air Pollutants on Forest Ecosystems in S.R. Slovenia1

Marjan Solar

INTRODUCTORY DATA

Slovenia w i t h i t s surface o f 20,251 km2 repre- sents 8% o f the t e r r i t o r y o f Yugoslavia (255,804 km2). It i s s i t ua ted i n the extreme northwestern p a r t o f the s t a t e between the Alps, the Pannonian p l a i n , the A d r i a t i c sea and the D ina r i c orographic system. Ha l f o f the surface i s covered by f o res t s (1,000,000 ha), 2/3 o f which a re p r i v a t e l y owned. The p o r t i o n o f con i f e r s amounts t o 56%, the average wood mass i s near l y 200 m3/ ha. The t o t a l increment per year i s 4,000,000 m3, the c u t t i n g 3,000,000 m3. Two-thirds o f the wood harvest possess a technica l value. The p o r t i o n o f f o r e s t r y w i t h i n the na t iona l income i s 4% and ind ica tes we l l the l eve l o f the i n d u s t r i a l development o f Slovenia.

Slovenia i s d iv ided up i n t o 15 f o r e s t management areas and each o f those i n t o the s o c i a l l y and p r i -v a t e l y owned sectors. The p r i n c i p l e s o f management are u n i f i e d . The bas ic p r i n c i p l e i s t o manage as much p rona tu ra l l y as poss ib le t o secure the perma-nency o f y i e l d and func t ions o f the f o res t . The f o r -es t se rv ice enjoys i n some places a 200-year t r a d i t i o n .

The study o f e f f e c t s o f a i r po l l u t an t s on the f o res t s goes back t o the year 1926, and systematic i n ves t i ga t i ons were s t a r t ed i n 1969.

OBJECTIVES OF INVESTIGATION

We wish t o determine the parameters, i n t e n s i t y and perspect ives o f the e f f e c t s o f a i r p o l l u t i o n on the f o res t s i n Slovenia, w i t h the aim t o secure r e l i a b l e foundat ions f o r the p lanning o f the indus-t r i a l development running p a r a l l e l l y w i t h the pre-serva t ion o f the mu l t i f unc t i ona l f o res t , f o r the r egu la t i on o f indemnit ies and the e labora t ion o f co r rec t normative concerning the maximum to l e rab l e concentrat ions va luable f o r t h i s s p e c i f i c f o r e s t area.

PRELIMINARY FOUNDATIONS REQUIRED

Ecology (geology, so i 1 s , phytocoenology , c l imate) as bases f o r the determinat ion o f f o r e s t ecosystems not stressed by emission, f o r e s t inventory as a ba-s i s f o r the determinat ion o f the normal management

P resen ted a t the Symposium on E f f ec t s o f A i r Po l l u t an t s on Mediterranean and Temperate Forest Ecosystems, June 22-27, 1980, Riverside, Ca l i f o rn i a , U.S.A.

~ r a d u a t e f o r e s t engineer, h igher research cooperator o f the I n s t i t u t e f o r the Forest and Wood Economy a t the Biotechnica 1 Facul ty i n L jub l jana , Yugoslavia.

s i t u a t i o n o f the f o res t s and a r e g i s t e r o f em i t t e r s .

METHODS OF ASSESSING THE EFFECTS OF POLLUTED AIR ON FORESTS

Symptomatics, chemical analyses, increment anal - yses, b io ind ica to rs , presence o f d i f f e r e n t l y aged needles, presence o f secondary pests, i n f r a c o l o r -aerophotographs.

SPECIFIC FEATURES OF THE TERRITORY OF SLOVENIA

Accentuated ~ o n f i g u r a t i o n ~ i n d u s t r yo f t e n located i n narrow va l leys , temperature invers ion, extremely h igh emission values (shocks), h igh p ropor t ion of suscept ib le con i fe rs , e rod i b l e s o i l s , predominancy o f SO2 and HF.

RESULTS OF INVESTIGATION

The t o t a l surface o f v i s i b l y damaged f o res t s i n S.R. Slovenia amounts t o 22,000 ha i .e . 2.2% o f the t o t a l f o r e s t area ( s i t u a t i o n i n 1977). The i n t e rna l d i v i s i o n o f damaged f o res t s i s the fo l low ing : Group A-the narrower emission area- the f o r e s t des-troyed and e x i s t e n s i a l l y threatened, o r surfaces under the impact o f c r i t i c a l emission cond i t i ons e n t a i l i n g the t o t a l des t r uc t i on o f a11 f o r e s t funct ions-dest ruct ion o f the f o r e s t ecosystem. Surface 4,000 ha. Group B-the wider emission area- forest under per-manent emission impact, ye t the ex is tence o f the f o r e s t i s not threatened, i t s funct ions are however reduced, o r surfaces under t o heavy emission con-d i t i o n s t o a l l ow a normal t h r i v i n g o f the f o res t . The emission causes an i n s t a b i l i t y o f f o r e s t eco-systems. Surface 16,000 ha. Group C-Periodic emission area-per iod ic occurrence o f damages, poss ib ly acute ones, but between i n d i v i d -ua l emission in f luences i n every case longer normal s i t u a t i o n s are in te rca la ted dur ing which the f o r -e s t can recover. Surface 2,000 ha.

Based on the chemical analyses o f Spruce needles as t o the increased content o f sulphur and f l u o r i d e , the surface o f f o res t s w i t h hidden i n j u r i e s i s es-t imated t o 25,000 ha. Survey and de ta i l ed maps of i n j u red f o r e s t have been made f o r a11 b igger emis-sions areas. On the basis o f r e l a t i v e res is tance capaci ty o f f o r e s t t rees and o f t h e i r p ropor t iona l presence i n the f o r e s t vegetat ion communities a ca tegor i za t ion o f f o res t s w i t h respect t o t h e i r s u s c e p t i b i l i t y t o a i r p o l l u t i o n has been c a r r i e d ou t .

The process o f a f u r t h e r improvement o f the emission damages i n the f o res t s observed dur ing the l a s t three years i s not l i k e l y t o proceed because o f the increase o f consumption o f coal possessing h igh contents o f combustible sulphur.

CONCLUSIONS

On the bas is o f i nves t iga t ions ca r r i ed ou t i n the t o t a l f o r e s t area o f Slovenia inf luenced by emission, o f knowledge concerning the ecology o f t h i s t e r r i t o r y and the p a r t i c u l a r i t i e s o f e f f e c t s o f the po l l u t ed a i r , we are ab le t o p red i c t exact-l y the fu tu re o f a c e r t a i n f o r e s t under c e r t a i n emission in f luence.

The s tandpoint o f f o res te r s i s always the f o l -lowing: Wherever the f o r e s t has been destroyed o r i s on the way o f des t ruc t ion , the a i r i s 10-c a l l y oo l l u t ed t o a r e l a t i v e l y c r i t i c a l extent . The a i r p o l l u t i o n i s too h igh a l so i n places where the f o r e s t i s hampered i n i t s development. Appealing t o the normatives f i x e d by law and concerning the maximum emission values allowed

means noth ing but t ha t the normatives are se t too h igh and t ha t the f o res te r s a re bound t o lower them.

o fThe Resolut ion issued on the xth ~ e e t i n ~ the IUFRO Group 2.09-Air Po l l u t i on , L jub l jana 1978 i s proposing the normatives insur ing the normal t h r i v i n g o f a11 k ind o f f o res t s on average and extreme s i t es . The values f o r SOi a re f o l l ow ing ( i n pg/m3/air) : 50 as year l y average, 100 as 24 h average, 150 as & h value, and f o r HF ( i n ug/m3/air) 0.3 as year l y average and 0.9 as & h value. For extreme s i t e s the normatives a re tw ice as sharp.

I f we compare the normatives f i x e d by Resolu-t i o n t o those f i x e d by law i n d i f f e r e n t coun t r ies we r e a l i s e the l a s t ones a re much too h igh.

Population Differences in Response to Sulfur Dioxide: a Physiological Analysis1

G. E. Taylor, Jr. and D. T. Tingey2

The environment e x e r t s a profound i n f l u e n c e on a p l a n t ' s a b i l i t y t o s u r v i v e and reproduce, and consequently v e g e t a t i o n i n a g iven a r e a w i l l possess a s e t of morphological and p h y s i o l o g i c a l t r a i t s t h a t enhance f i t n e s s . A t t h e l e v e l of popu la t ions , t h e s e s i t e - s p e c i f i c a t t r i b u t e s a r i s e through e i t h e r a modi f i ca t ion of t h e phenotype (phenotypic p l a s t i c i t y ) o r a change i n t h e gene pool (ecogenet ic a d a p t a t i o n ) . Both responses a r e common s t r a t e g i e s among n a t u r a l popu la t ions exper- i enc ing d i s p a r a t e c l i m a t i c , edaphic and b i o t i c s t r e s s e s . It is hypothes ized t h a t e l eva ted l e v e l s of a tmospher ic p o l l u t a n t s have e l i c i t e d i n a com-p a r a b l e manner a v a r i e t y of t r a i t s t h a t enhance s u r v i v a l and rep roduc t ion i n n a t i v e p l a n t s inhab- i t i n g p o l l u t i o n - s t r e s s e d a r e a s .

One example of ecogene t i c a d a p t a t i o n i n response t o a i r p o l l u t i o n i s t h e evo lu t ion of s u l f u r d i o x i d e r e s i s t a n c e w i t h i n popu la t ions of Geranium carol in ianum, a n herbaceous w i n t e r annual common i n d i s t u r b e d h a b i t a t s i n t h e Sou theas te rn United S t a t e s . I n comparison wi th t h e i r counter- p a r t s from p o l l u t i o n - f r e e r eg ions , popu la t ions sampled from a r e a s exper i enc ing v a r i a b l e SO2 s t r e s s f o r 3 1 y e a r s were c o n s i s t e n t l y more r e s i s -t a n t t o SO2 under c o n t r o l l e d exposure cond i t ions . This i n f r a s p e c i f i c v a r i a t i o n i s g e n e t i c a l l y de te r - mined and q u a n t i t a t i v e l y c o n t r o l l e d . P l a n t s of c o n t r a s t i n g SO2 r e s i s t a n c e were used t o invest!+ g a t e t h e p h y s i o l o g i c a l b a s i s of t h i s adap ta t ion . I n d i v i d u a l p l a n t s were p laced i n a whole-plant gaseous exchange system i n which concurrent s t e a d y s t a t e measures of l e a f r e s i s t a n c e t o water vapor e f f l u x and SO2 i n f l u x were monitored i n t h e da rk and l i g h t a t p o l l u t a n t concen t ra t ions of 0.4, 0.6, and 0.8 u l 1-l. For r e s i s t a n t and s e n s i t i v e p l a n t s a t each concen t ra t ion , e s t i m a t e s of t o t a l SO2 f l u x (pg c m 2 h r l ) a s a f u n c t i o n of l e a f r e s i s t a n c e t o Hz0 e f f l u x were modeled us ing l i n e a r r e g r e s s i o n techniques . From e s t i m a t i o n procedures , t o t a l f l u x was p a r t i t i o n e d i n t o l e a f s u r f a c e and i n t e r n a l f r a c t i o n s .

T o t a l SO2 f l u x v a r i e d a s a f u n c t i o n of l e a f r e s i s t a n c e and d i d n o t d i f f e r among r e s i s t a n t and s e n s i t i v e p l a n t s a t 0.4 and 0.6 u l l 1SOz. Con-v e r s e l y , a t t h e h i g h e s t concen t ra t ion t o t a l SO2 f l u x was n o t t h e same f o r t h e 2 p l a n t groups a s a consequence of d i s p a r a t e s l o p e parameters. I r r e -s p e c t i v e of concen t ra t ion t h e l e a f s u r f a c e and i n t e r i o r were major s i n k s f o r SO2 (Fig. 1 ) . Each f r a c t i o n inc reased l i n e a r l y wi th concen t ra t ion ,

'presented a t t h e Symposium on E f f e c t s of A i r P o l l u t a n t s on Medi ter ranean and Temperate F o r e s t Ecosystems, June 22-27, 1980, R ive r s ide , C a l i f o r n i a , U.S.A.

2 ~ o s t d o c t o r a l Assoc ia t e and P l a n t P h y s i o l o g i s t , T e r r e s t r i a l Divis ion, U.S. Environmental Protec- t i o n Agency-Corvallis Environmental Research Laboratory, C o r v a l l i s , Oregon, U.S.A.

however t h e r a t i o of i n t e r n a l t o t o t a l f l u x decreased s t e a d i l y . The a b s o l u t e v a l u e s f o r i n t e r - n a l SO2 f l u x were s t r i k i n g l y s i m i l a r f o r bo th p l a n t groups a t each concen t ra t ion . Therefore , i n s p i t e of t h e v a r i a t i o n i n t o t a l SO2 f l u x t o t h e p l a n t , t h e r a t e of SO2 absorbed i n t o t h e l e a f i n t e r i o r was equ iva len t f o r r e s i s t a n t and s e n s i - t i v e p l a n t s . S ince l e a f r e s i s t a n c e t o wa te r vapor e f f l u x i s t h e same f o r a l l p l a n t s i n both ambient and S02-polluted atmospheres, o v e r t p lant - to-plant d i f f e r e n c e s i n t h e i r response t o SO2 r e f l e c t d i s p a r a t e i n t e r n a l biochemical p rocesses a f f e c t i n g po l lu t a f i t t o x i c i t y , p e r t u r b a t i o n o r c e l l u l a r r e p a i r .

The f a c t t h a t p l a n t d i f f e r e n c e s i n response t o SO2 a r e g e n e t i c a l l y c o n t r o l l e d and n o t a r e s u l t of p o l l u t a n t exc lus ion i s r e l e v a n t t o an unders tanding of t h e r a p i d evo lu t ion of popula t ion r e s i s t a n c e i n

-G. carolinianum. This s p e c i e s i s an annual t h a t t h r i v e s f o r s i x months a s a win te r r o s e t t e du r ing which new l e a f growth i s minimal and y e t t r ans -p i r a t i o n remains a c t i v e . This h a b i t coupled w i t h t h e p l a n t ' s i n a b i l i t y t o t r a c k and exclude e l e - va ted l e v e l s of SO2 may p red i spose t h i s s p e c i e s t o accumulate more SO2 d e r i v a t i v e s than o t h e r co-occurring s p e c i e s t h a t a r e e i t h e r more ephemeral o r capable of avoiding SO2 uptake i n c r e a s i n g s tomata1 r e s i s t a n c e . These s p e c i e s ' a t t r i b u t e s may e x p l a i n t h e c o n s i s t e n t f i e l d obse rva t ions t h a t show c. carolinianum t o be a s e n s i t i v e b i o l o g i c a l i n d i c a t o r of e l eva ted SO2 l e v e l s .

Acknowledgments: Research sponsored by t h e Nat ional Academy of Sciences-National Research Council through a Pos tdoc to ra l Research Associa te- s h i p t o t h e s e n i o r author . Senior au thor acknow- l edges suppor t f o r manuscript p r e p a r a t i o n under Contrac t W-7405-eng-26 by t h e Department of Energy wi th Union Carbide Corporation, a t Oak Ridge Nat ional Laboratory, Oak Ridge, Tennessee.

6.0 , t r

- RESISTANT PLANTS SENSITIVE PLANTS-

SULFUR DIOXIDE CONCENTRATION ( p l I"')

Figure I--Absolute v a l u e s f o r t o t a l , s u r f a c e and i n t e r n a l l e a f f l u x of SO2 a s a func t ion of p o l l u t a n t concen t ra t ion i n r e s i s t a n t and' s e n s i t i v e p l a n t s .

1

Ozone Injury to Pines in the Southern Sierra Nevada of California1

2Det lev R. Vogler and John Pronos

The Forest Serv ice began eva lua t ing the impact o f ozone on S ie r r a Nevada f o res t s i n 1974. Eval-ua t ion e f f o r t s were expanded and i n t e n s i f i e d i n 1977, and s ince then t he pr imary methods o f assessment have included, (1) moni tor ing ambient ozone levels, and (2) r a t i n g i n j u r y t o p ine f o l - iage i n permanent t r end p l o t s .

A i r p o l l u t i o n i n j u r y t o commercial p ine stands located between 4000 and 8000 f e e t e l eva t i on occurs q u i t e un i fo rm ly along most o f the southern S ie r ra Nevada f r o n t range adjacent t o the San Joaquin Va l ley and up i n t o t he major r i v e r dra in- ages. Symptoms a re n o t conf ined t o loca l i zed areas downwind from major p o l l u t a n t sources. Rather, ozone i s c a r r i e d down the e n t i r e San Joaqu in A i r Basin and eastward i n t o t he Sier ra . MetropoI i t a n areas c o n t r i b u t i n g t o the ozone dose inc Iude Stockton, Modesto, Merced, Fresno, Visa1 i a Bakersf ie ld , and perhaps even Sacramento and the San Francisco Bay Area.

OZONE MONITORING

F i ve fo res ted loca t ions i n t he southern S ie r r a were moni+ored f o r season-long ozone dosages between 1977 and 1979. One s i t e -- Whitaker Fores t -- was monitored cont inuously dur ing t h i s 3-year per iod. The s i t e s ranged i n e l eva t i on from 5400 f e e t t o 7540 feet , and a l l were a t l e a s t 50 m i l es from suspected met ropo l i tan sources o f a i r p o l l u t i o n .

Ozone l eve l s a t each s i t e exceeded both t h e Federal (0.12 ppm) and S ta te (0.10 ppm) Standards each year they were recorded. Based on t he num-ber o f hours exceeding t he Standards, 1977 was t h e wors t year f o r ozone, wh i l e l e ve l s dec l ined s t e a d i l y i n 1978 and 1979. During t he summer o f each year d a i l y peak ozone values commonly ranged between 0.10 ppm and 0.14 ppm. These values can be compared t o those i n t he San Bernardino Moun- t a i n s o f southern Ca l i f o rn i a , where maximum d a i l y ozone leve ls f requen t l y range from 0.20 t o 0.33 ppm, and where i n j u r y t o p ine f o res t s i s corres- pondingly more severe.

TREND PLOTS

Presented a t t he Symposium on E f f ec t s o f A i r Po l l u t an t s on Mediterranean and Temperate Forest Ecosystems, June 22-27, 1980, Riverside, Ca l i f o rn i a , U.S.A.

'plant Patho loq is ts , P a c i f i c Southwest Region, Fores t Service, Ui s . ~epartment of Agr icu ture, San Francisco, Ca I i f o r nia.

Trend p l o t data were co I lected f o r t h ree con- secut ive years beginning i n 1977. I n 1977 and 1978 ozone i n j u r y r a t i n g s o f p l o t s scat tered throughout a sampl ing area o f over 1 m i I l ion acres ranged between no i n j u r y and moderate i n j u r y . A l -though t he ma jo r i t y o f 1978 p l o t s showed more ox i - dant symptoms than 1977 p lo ts , t he re was no sta- t i s t i c a l l y s i g n i f i c a n t t rend evident. The change between 1977 and 1979, however, was more dramatic. Nineteen o f 27 p l o t s evaluated i n 1979 showed add i t i ona l i n j u r y over 1977 levels, and seven o f these p l o t d i f fe rences were s t a t i s t i c a l l y s i g n i f i - can t (P = 0.05). I n 1979, f o r t h e f i r s t time, several p l o t s f e l I i n t o t he severe i n j u r y category. The t r ees i n these p l o t s averaged 2 years o f needle r e t en t i on w i t h ozone symptoms on Z-year- ol'd needles.

Th is obvious increase i n i n j u r y was n o t expected because measured ozone l eve l s i n 1979 were genera l l y lower than i n e i t h e r 1978 o r 1977. Considerable phys io log ica l s t ress from a 2-year drought (1976-1977) could account f o r p a r t o f t he observed increase i n f o l i a r i n j u r y . One v i s i b l e response o f pines t o t he drought was a dramatic decrease i n needle re tent ion, which tended t o produce more severe ozone i n j u r y ra t ings . Future recovery o f t r ees from drought stress, i n t h e form o f increased needle re tent ion, may r e s u l t i n a r e l a t i v e reduct ion o f measureable a i r p o l l u t i o n i n j u r y dur ing t h e nex t few years.

CONCLUSIONS

The ove ra l l leve l o f forest-wide i n j u r y i n t h e south'ern S ie r ra Nevada can be termed s l ight, w i t h some loca l populat ions o f suscep t ib le pines showing moderate o r worse i n j u r y . Unexpectedly h igh amounts o f i n j u r y detected i n c e r t a i n areas i n 1979 placed some p l o t s i n t o t h e severe category. I t i s p resen t l y unc lear whether t h i s i s a perma-nent t rend of increasing impact, o r j u s t a short-term r e s u l t o f drought stress.

With on ly 3 years o f moni tor ing data, t rends i n annual ozone dose a re d i f f i c u l t t o assess. Ozone leve ls seemed t o decrease s l i g h t l y each year between 1977 and 1979, even though v i s i b l e i n j u r y t o pines increased. Measured va r i a t i ons i n seasonal ozone dose may be associated more w i t h weather pa t te rns than w i t h decreased pol Iu tan ts a t t he source. Maximum d a i l y ozone values i n t h e S ie r r a s t i l l remain about 1/2 o r less of those occur r ing i n southern Ca l i f o rn i a . As ozone con- t i nues t o be t ranspor ted i n t o t he western slopes o f t he S ie r r a Nevada, s e n s i t i v e pines w i l I con-t i n u e t o show add i t i ona l i n j u r y and w i l I s low ly decl lne.

Modifications of Chemical Contents of Precipitation by Passage through Oak Forests1

George T. Weaver and Jon D. ones^

Bulk precipitation monitored within oak forests in the Ozark Physiographic Province in Illinois was strongly acidic (pH<4.5) throughout most of

. 1978. Exceptions occurred during late summer and early autumn when pH rose to 5.8. This pattern with similar pH values reoccurred during the autumn and winter of 1979-80 and differs from seasonal trends usually reported from the northeast- ern United States where periods of greatest and least acidity are summer and winter, respectively. During the 1979-80 period, the highest concentrations of ~ 0 ~ ~ - occurred durin~ autumn, and on an equivalence basis, exceeded H concentrations by a factor of 10. Concentrations of ~ a , ~ g and, K+ were also high during autumn. It is hypothe- sized that considerable neutralization of strong acids occurred in the atmosphere due to the presence of airborne dust which normally exists during autumn.

Additional neutralization occurred as precipitation passed through the forest canopy, especial-ly during autumnal leaf senescence. At this time canopy drip pH exceeded bulk precipitation

2qH by up to 0.7 units. The concentrations of Ca , in canopy drip increased Mg2, K', 804 and ~ 0 ~ ~ -

markedly compared to bulk precipitation, particu-larly during autumn. During the winter, canopy drip pH decreased to values as low as 3.8 and differed little from bulk precipitation pH. In 1978, 68 percent of the precipitation reaching the forest floor as canopy drip was acidic (pH<5.6). The removal of nutrient ions from the canopy also de-


~ssociate Professor of Forestry, Southern Illinois University, Carbondale, 111.; Forestry Aide, Baruch Science Institute, Georgetown, S.C.

creased during winter. In the spring of 1980 maximum bulk precipitation pH was 6.6 but passage through the canopy caused a decrease in pH as great as 0.8 units. Soluble organic compounds, apparently leached from some oaks, were present in sufficient quantities to impart a dark stain to canopy drip during this period and may be associated with the reversal in H exchange in the canopy.

The concentrations of ions in soil water fonn- ed three distinct patterns relative to concentrations in bulk precipitation and canopy drip. Hy-drogen ion concentration was decreased markedly by passage through these ecosystems and the quantity remaining in soil water was only about 10 percent as great as in bulk preci itation. The concentrations of four ions - So:-, m3-, ca2+- and W2+- increased as water passed through these ecosystems. The levels of these ions in soil wa-ter were as great as 37 times and 9 times the levels in bulk precipitation and canopy drip, respectively, although major differences occurred among seasons and between ions. The contents of K+ and ~ 0 ~ - in bulk precipitation also were increased by up to 25 times by passage through the forest canopy. However, concentrations of these particular ions either decreased or remained similar to concentrations in canopy drip after passage through the soil.

Between October 1979 and April 1980, ca2+ and sod2-were the predominant ions (equivalence basis) associated with meteorologic and hydrologic processes in these ecosystems. The importance of Ca 2+ in these ecosystems was anticipated since it is selectively accumulated by some species of oaks in these forests. It is also apparent that elevated levels of H' are being deposited in association with in these ecosystems, but the impacts remain undetermined.

2

Seasonal Variation of Inorganic and Organic Sulfur in Coniferous Needles Intensified by SO2 Pollution '

2Karl Friedrich Wentzel und SUnther Gasch

Method:-Needles front 50 - 70 year o ld Norway spruce from 1. gardens and

parks of Wiesbaden town (s l ight damage), 2. and Wiesbaden forests

(no v is ib le injury) were used as bioindicators fo r $0.-uptake.

I n octobre we picked 0.5, 1.5 and 2.5 year old needles, i n m y

we picked 1, 2 and 3 year o ld needles fro@the tops of the sam

trees. Inorganic and organic sulfur was determined according t o

JSger und Steubing (1970).

Results:-1. Air pol lut ion measuremnt 1976 - 1979. Datas i n microgram

SO per cbw air. 11= annual average, 12 = 95 percentile of

30 win. values:

Zone II 1 2

Industr ia l Area 120 - 140 400 - 500

Town 7 0 - 90 200-300

Forests <50 <120

2. Total sulfur content increases with needle age as shown i n

fig. 1 :Map of Wiesoaden/FRG

Fig. 2. I n town the S contents d the needles are 100 - 200 ppm

higher than those froa the forests.

3. The inorganic f ract ion of a l l needle samples surmounts the

organic fraction. The difference i s greater i n autumn than i n

spring and more apparent i n town than i n the forests.

4. The va l id i ty of using coniferous needles as indicator of a i r

pol lut ion effects i s best when octobre datas of inorganic S are

used.

5. Organic sul fur content decreases during the vegetation period

while the inorganic f ract ion increases. During winter time the

opposite occurs (Fig. 3). From th i s i t i s suggested that i n

spring t i ne a part of the organic sulfur d m n d i s covered by

remvinq the inorganic amount, which par t ia l l y i s of air-borne

origin.

1 Presented a t the In ternat iona l Symposium on E f f ec t s o f A i r Po l lu tan ts on Mediterranean and Temperate Forese Ecosystems, June 22-27, 1980, Riverside, Ca l i fo rn ia , U.S.A.

2 Forest Ecologist and chemist, respect ively, Hessische Landesanstalt f u r Umwelt, Wiesbaden, West Germany

500. - Wiesbaden Town

-- - -- Wiesbaden Forest 300

0.5 1.0 1.5 2.0 25 3D Needle4 e

Fig. 2 :Sulfur content ( p p of dr. wt.) i n spruce needles from Wiesbaden town (means of 39 tree samples) and forests (mans of 16 tree samples).

Oclobre- deltas

. . . . May -deltas

1 A Decrease of inoro.S

I -Wiesbaden Town 39 trees in casualorder

Fig. 3 :Seasonal alteration of inorganic and organic S i n spruce needles frw Wiesbaden town (mans of 6 semi-annual needle sets).

Sulfur Dioxide and Oxidant Effects on Californian Coastal Sage Scrub1

W.E. Westman and K.P. pres tonz

Two f i e l d s t u d i e s have r e l a t e d o x i d a n t and f r e e upwind s t t e s . I n j u r y t o i n d i v i d u a l S a l v i a s u l f u r d i o x i d e p o l l u t i o n t o a d e t e r i o r a t i o n i n shrubs and changes i n community s t r u c t u r e and t h e s t r u c t u r e and f u n c t i o n o f southern C a l i f o r - f l o r i s t i c compos i t ion were recorded. Stomata1 n i a ' s drought-deciduous shrublands ( coas ta l sage r e s i s t a n c e was found t o be s i g n i f i c a n t l y lower scrub) . I n a s tudy o f 67 s i t e s (0.63ha) f rom on t h e p o l l u t e d s i t e s w i t h a concomitant 35 pe r - San Franc isco t o E l Rosar io (Ba ja C a l i f o r n i a ) , cen t i nc rease i n mean t r a n s p i r a t i o n r a t e s o f da ta were c o l l e c t e d on spec ies cover and 43 Sa lv ia . F lower ing capac i t y o f S a l v i a , measured h a b i t a t v a r i a b l e s d e s c r i b i n g topography, s o i 1 , by the number o f f l o w e r whor l s p e r f l o w e r sp i ke , c l i m a t e , v e g e t a t i o n s t r u c t u r e , age s i n c e f i r e , was a l s o s i g n i f i c a n t l y reduced. S i g n i f i c a n t g r a z i n g i n t e n s i t y , and a i r p o l l u t i o n o f s i t e s . decreases i n t h e h e i g h t / w i d t h r a t i o o f S a l v i a The v a r i a b l e which showed t h e h i g h e s t s i q n i f i - were hypothes ized t o be caused by s u l f i t e - c a n t c o r r e l a t i o n w i t h pe rcen t f o l i a r cover o f mediated d e s t r u c t i o n o f i n d o l e a c e t i c a c i d (Yang n a t i v e species was t h e mean annual o x i d a n t and Saleh, 1973) and p o s s i b l e i n h i b i t i o n o f concen t ra t i on (r=-.58, P<.001). E l e v a t i o n and a p i c a l dominance. S i g n i f i c a n t reduc t i ons i n mean maximum temperature o f t h e warmest month photos.ynthetica11.y a c t i v e t i s s u e o f S a l v i a a l s o showed h i g h l y s i g n i f i c a n t c o r r e l a t i o n s r e s u l t e d f rom increased d e f o l i a t i o n and r e d u c t i o n ( r=- .52) . The p a r t i a l c o r r e l a t i o n c o e f f i c i e n t s i n l e a f s i z e assoc ia ted w i t h SO2 s t r e s s . The o f ox idan ts w i t h pe rcen t cover remained h i g h evidence i n d i c a t e s t h a t these f a c t o r s decreased when c o v a r i a t i o n s w i t h e l e v a t i o n , mean maximum t h e shrubs ' a b i l i t y t o compete w i t h t h e more r-temperature o f t h e warmest month ,and d i s t a n c e s e l e c t e d annuals. As such, t h e number o f f rom t h e coas t were e x t r a c t e d ( r= - .41,- .35,- .42 species, p r i m a r i l y annuals, increased cons ider - r e s p e c t i v e l y ) . The i n t e r r e l a t i o n s h i p s o f these a b l y i n t h e most o o l l u t e d s i t e s (X=27 v. 7=18.on v a r i a b l e s were i n v e s t i g a t e d f u r t h e r by means o f c o n t r o l s i t e s ) . These SO2 -assoc ia ted changes pa th a n a l y s i s . A p a t h model (ch i -square probab i - i n community s t r u c t u r e and f l o r i s t i c compos i t ion l i t y = .87) r e l a t e d environmental f a c t o r s t o a suggest t h a t r e t r o g r e s s i o n i s occu r r i ng , caus ing r e d u c t i o n i n t h e pe rcen t cover o f n a t i v e species. t h e 26-year o l d s tand t o resemble a 7-year o l d The p a t h model suggested t h a t o t h e r f a c t o r s co r - p o s t - f i r e sera1 's tage. Resu l ts a re r e p o r t e d r e 1 a ted w i t h dec l in i ng cover were a c t i n g p r i m a r i - more f u l l y i n Pres ton (1 980). Laboratory s t u d i e s 1y through t h e i r i n f l u e n c e on o x i d a n t concentra- a re i n progress t o assess s e n s i t i v i t y o f sage t i o n i n p r e d i c t i n g t h e d e c l i n e i n cover o f n a t i v e scrub species t o SO2 i n j u r y . scrub species.

I n c r e a s i n g concen t ra t i ons o f ox idan ts were a l s o assoc ia ted w i t h a d e c l i n e i n species r i c h -ness (r=-.23; P<.05) and i nc rease i n e q u i t a - b i l i t y ( W h i t t a k e r ' s Ec index; r=.24; P<.05). D i v e r s i t y i n f l o r i s t i c a l l y s i m i l a r s i t e s o f h i g h and low annual o x i d a n t concen t ra t i ons was compared. H i g h l y p o l 1 u ted s i t e s have fewer species p e r abundance c l a s s and a l ower t o t a l species r i chness ("7=18 v . T=29 a t l e s s p o l l u t e d s i t e s ) . Concent ra t ion of dominance increases i n t h e more p o l l u t e d s i t e s . Major r e s u l t s have been r e p o r t e d i n Wes tman ( 1 979).

I n a second f i e l d study, t h e e f f e c t s o f s u l f u r Preston, K.P.d i o x i d e emissions (up t o 0.13 ppm f o r a p e r i o d o f 1980. E f f e c t s o f s u l f u r d i o x i d e p o l l u t i o n on25 y e a r s ) from an o i l r e f i n e r y were s t u d i e d near coas ta l sage scrub. M.A. Thesis. DepartmentSanta Maria, on t h e r u r a l c e n t r a l coas t o f C a l i - o f Geography, U n i v e r s i t y o f C a l i f o r n i a , Losf o r n i a . Stands o f coas ta l sage scrub w i t h b l a c k Angel es . sage (Sal v i a me1 1 if e r a ) downwind o f t h e r e f i n e r y were compared w i t h stands i n r e l a t i v e l y p o l l u t i o n - Westman, W.E.

1979. Ox idant e f f e c t s on C a l i f o r n i a n coas ta l sage scrub. Science 205:1001-1003.

Â¥'Â¥presenta t t h e Symposium on E f f e c t s o f A i r Whi t t a k e r , R.H. P o l l u t a n t s on Medi terranean and Temperate Fo res t 1972. E v o l u t i o n and measurement o f species Ecosystems, June 22-27, 1980, R ive rs ide , d i v e r s i t y . Taxon 21 :213-251. C a l i f o r n i a , U.S.A.

Yang, S.F. and S.A. Saleh. ' ~ s s o c i a t e P ro fesso r o f Geography and graduate 1973. D e s t r u c t i o n o f i ndo le -3 -ace t i c a c i d

s tudent , r e s p e c t i v e l y , U n i v e r s i t y o f C a l i f o r n i a , d u r i n g t h e ae rob ic o x i d a t i o n o f s u l fit e . Los Angeles, Cal i f o r n i a. Phytochemistry 12:1463-1466.

Miller, Paul R., technical coordinator. I

1980. Proceedings of the symposium on effects of air pollutants on Mediterranean and temperate forest ecosystems, June 22-27, 1980, Riverside, California, I U.S.A. Gen. Tech. Rep. PSW-43,256 p. Pacific Southwest Forest and Range Exp. 1 Stn., Forest Sew., U.S. Dep. Agric., Berkeley, Calif. 1

I II

These proceedings papers and poster summaries discuss the influence of air pollution on

relationships; interactions of producers, consumers, and decomposers under pollutant II terrestrial and related aquatic ecosystems. They describe single species-single pollutant

I

I stress; and the use of ecological systems models for interpreting and predicting pollutant Ieffects.

I Retrieval Terms: air pollution injury, acidic precipitation, pollutant stress, terrestrial I I habitats, species-pollutant relationship. mathematical models. I

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