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ABSTRACT
Site specific growth data for the 3 yearsfollowing fertilization and thinning are given for theShawnigan research plots. The data base is documented and gross and merchantable volume, andcumulative dbh and height increments are given.Evaluation of treatment response is investigatedusing individual tree increments (dbh, ba, heightand gross volume), stand structure analysis and croptree analysis.
Significant early treatment responses areshown. By using covariance analysis with the 618largest trees/ha as the crop trees, the percent gain ingross volume increment over the adjusted controltreatment was 54, 110 and 188, respectively, forheavy thinning without fertilization, heavy fertilization with no thinning, and heavy thinning andheavy fertilization combined.
The analytical approaches used are compared and reader feed-back is solicited.
Key words: 3-year growth, individual trees, standstructure, crop trees, Pseudotsugamenziesii
'i-,)r..,K7 l l/,};l )(
RESUME
Les parcelles de recherche aShawnigan antfourni des donnees specifiques de croissance sur desstations pour les 3 annees qui ont suivi leur fertilisation et leur eclaircie. Le fichier central est (hoffeet indique I'accroissement des volumes brut et marchand, du dhp cumulatif et de la hauteur des arbres.Les auteurs evaluent les facteurs de la reponse auxtraitements en utilisant les accroissements chezchaque arbre (du dhp. de la surface terriere, de lahauteur et du volume brut), I'analyse de la structuredu peuplement et I'analyse des arbres du peuplementfinal.
Des reponses significatives et rap ides sontici presentees. En utilisant une analyse de covariancedes 618 plus gros arbres par hectare comme arbresdu peuplement final, Ie gain en pourcentage d'accrois·sement du volume brut par rapport aux arb res temoins(dont les caracteristiques avaient ete ajustees) fut de54,110 et 188 respectivement pour les parcelles treseclaircies sans fertilisation, fertilisation pronouncesans eclaircies et un traitment combine des parcellestres fertilisees et tres eclaircies.
On fait une comparaison des methodesd'analyse, et a ce sujet les observations du lecteurseront appreciees.
2
TABLE OF CONTENTS
Page
ABSTRACT .
1.0
2.0
INTRODUCTION .......................•......•••.....••...
OOCUMENTATION OF THE DATA BASE ......••.....•......•••.....
5
5
2.1 Units of measurement , , . . . . . . . . . . . . . . . . . . . . . 5
2.2 Measurements on a plot basis , , . . . . . . . . . . . . 5
3.0
2.3
2.4
2.5
3.1
3.2
Measurements on an individual tree basis . ..............•.•....•......•
Volume determination . ..
Data recorded for all plot trees. ......••...................•....
3·YEAR GROWTH RESPONSE...........................•....
Volumes per hectare produced in the first 3 years followingtreatment. . ........................................•......•
Cumulative increment for dbh and height .
6
6
7
8
8
10
4.0 ANALYSIS OF GROWTH RESPONSE OF INDIVIDUAL TREES ........••... 10
4.1
4.2
4.3
4.4
Dbh increment (em/ann) ..
Sa increment (cm 2/annl ..
Height increment (m/ann) . ............•....................••....
Gross volume increment (m3/ann) .
10
13
13
13
5.0 METHODS OF EVALUATING TREATMENT RESPONSE ON APER HECTARE BASIS ...............................••.....•...... 13
5.1
5.2
Stand structure analysis , .
Crop tree analysis .
..........................
..........................
14
19
6.0 COMPARISON OF ANALYTICAL PROCEDURES.........••......••.... 19
7.0 SUMMARY . ............... . . .. " . 20
8.0
9.0
ACKNOWLEDGMENTS....•.........••....•... ..... , .
REFERENCES ..........••...•....•... .....................
21
21
10.0
Appendix I
Appendix II
Appendix III
Appendix IV
Appendix V
Appendix VI
Appendix V II
3
APPENDICES
Plot measurement schedule.
Regression equations for estimating 3-year height increment by treatment . ..
Merchantable volume factor equations. ..
Gross and merchantable volumes by treatments..
Regression equations by treatments for periodic annual increment
(dbh, ba, height and gross vo lume) . . . . . . . . .
Dbh frequency distributions by treatments showing initial condition
and number of trees lost through thinning and mortality . ..
PAl for dbh by dbh classes and treatments.
Page
22
23
24
25
26
29
30
Appendix VIII PAl for ba by dbh classes and treatments. 31
Appendix IX
Appendix X
Appendix XI
Append ix X II
PAl for height by dbh classes and treatments
PAl for volume by dbh classes and treatments.
Tree frequency distributions by dbh class and treatment used
in stand structure analysis. . . . .. . .....
Actual and adjusted PAl for gross volume by covariance analysis
using the 395 and 618 largest trees per hectare. . . .
32
33
34
36
4
LIST OF TABLES
Page
Table 1
Table 2
Figure 1
Figure 2
Figure 3
Figure 4
Figure 5
Figure 6
Figure 7
Figure 8
Initial mean dbh and height for the 395 and 618 largest trees per hectare.
Table of significance for fertilization, thinning and interaction using the
395 and 618 largest trees per hectare. . . . .....
LIST OF FIGURES
Gross and merchantable volume per hectare by treatments
Cumulative dbh increment by treatments for dbh class 4..
Cumulative height increment by treatments for dbh class 4 .
PAl for dbh by dbh classes and treatments.
PAl for ba by dbh classes and treatments ..
PA I for height by dbh classes and treatments
PAl for gross volume by dbh classes and treatments. ,
Calculated PAl for gross volume of healthy Douglas-fir on a perhectare basis. . . . . . . . . .
18
18
8
9
9
11
11
12
12
14
Figure 9 Treatment response by stand structure 3nalysis using actual treefrequency distributions. . . .....
Figure 10 Treatment response by stand structure analysis using mean treefrequency distribution for each thinning level. . . . . .
Figure 11 Treatment response by stand structure analysis using hypotheticaltree frequency distribution. . .....
Figure 12 Actual and adjusted treatment response by covariance analysis usingthe 395 and 618 largest trees per hectare ..
15
16
17
17
5
1.0 Introduction
Interest in forest fertilization and thinning ishigh in the Pacific Northwest. How best to measureand evaluate treatment response in the most"uniform" of heterogeneous forests is still an openquestion. Attention has recently been focussed onthe development of procedures for handling variationin response (Anon, 1975), and on reporting grossvolume growth (Miller and Pienaar, 1973), Earlyresponses reported have been significant and the dataproduced will be invaluable as input into decisionmaking models for forest management. As researchprogresses, the need for regionally accepted analysisprocedures will become important if results are to bereadi Iy interpreted.
Details of the site, experimental basis, and themultidisciplinary nature of the project at ShawniganLake, B.C. have been previously reported (Crown,Brett et ai., 1975). The study area was establishedin 1970 in a young 24-year-old Douglas-fir stand, at335 m elevation, on shallow, coarse textured soils(Orthic Dystric BrunisolsL Site index was 21 m at50 years. The basic experiment consisted of a 3 x 3
completely randomized factorial design comprising3 levels of nitrogen fertilization [0 (FO), 224 IF1)and 448 IF2). kg N per ha as urea) applied in thespring, and 3 levels of thinning in which zero (TO),and about 1/3 (Tl) and 2/3 IT21 of the basal areawas removed. Treatments were replicated twicein each of 2 years (1971 and 19721 in plots of 0.04ha surrounded by 10-m·wide buffer zones.
This report is based on only 3 years of growthfollowing fertilization and thinning and results aresite specific. Emphasis, therefore, is placed on thediscussion of analysis procedures rather than onabsolute response values. The report documentsthe data base, gives gross and merchantable volumegrowth on an area basis, cumulative increments fordbh and height, growth of individual trees in respectto dbh, ba, height, and gross volume, and resultsfrom individual trees. Stand Structure (Anon, 1975)and "Crop Tree" analyses are discussed. Manyquestions on analysis procedure are unanswered andreader feed-back is solicited.
2.0 Documentationof the data base
Data and analyses included in this reportare based on measurements taken at the time ofinstallation establishment and for the 3 years following treatment. It is recognized that 3-year resultswill give only initial treatment response. Reportingplanned for 6, 9, 12 and 15 years' post treatment(coincid ing with the measurement schedule inAppendix I) will provide increasingly more reliableestimations of the total response to fertilizationand thinning. Analysis showed no significantdifference between the response for the 1971 and1972 installations and hence the data were pooled,giving 9 treatments each with 4 replications.
A number of initial analyses were also conducted using Canadian yard/pound measures.
The measurement of trees involved two distinct strategies, a plot basis and an individual treebasis.
units. In conversion to metricunconventional sizes exist.
i) plot size is 0.0404 ha (1/10 acre).ii) breast height was defined as 1.372 m
(4.5 ftliii) taper steps were at 2.54 cm dob (1 inch)
intervals.ivl diameter class intervals were 2.5 cm
(approximately)v) equations for dbh, basal area, height,
height increment, gross volume and merchantable volume use Canadian yard/pound measures.
Canadian yard/poundunits, some ratherExamples are:
Units of Measurement2.1
At the time of inception of this study, metricconversion appeared to be far in the future; consequently, the installation was established using
2.2 Measurements on a plot basis
The plot basis is used to evaluate initial plot
condition and to monitor changes at fixed timeintervals through the course of the experiment.
The kind and frequency of measurementstaken are:
aJ dbh over bark (ob) and tree conditionfor all plot and buffer trees were recordedat the time of establishment and annuallyfor the succeeding 3 years; future recordings wi II be at 3·year intervals; was measured using dbh tapes;
b) height of all plot trees and thinned buffertrees was measured with height poles atthe time of plot establishment. Height ofplot trees will be measured at 3·yearintervals;
6
as defined by Competitive Stress Index (CSll.
Measurements taken were:-
a) dbhob initially and annually thereafter.
b) total height annually from 3 years preceding establishment.
e) dob at 0.305 m and at 2.54 em (approx)
stem diameter taper steps measured to a7.62 em minimum dob for larger treesand to half height above dbh for thesmaller trees; these measurements weretaken 3 years after treatment and willbe taken at 3-year intervals until the conclusion of the study.
2.4 Volume determinationc) height to live crown was measured with
height poles at the time of establishment;subsequent measurement will be made at 6years following establishment and at3-year intervals thereafter;
d) all plot and buffer trees were stem mappedat the time of establishment (prior tothinning). Tree locations were originallymapped using the azimuth-distance methodand later checked using right angledprisms and tapes (now the preferred procedure); and
eJ Competitive Stress Index at dbh (Arney,1973) was calculated for all plot treesfrom dbh measurements and stem maps.
The total number of trees in all plots at plotestablishment was 13,273. The number of plot treescurrently being measured is 3,951.
To determine initial individual tree and initialplot volumes, a local volume equation was developedfor the site. It was derived prior to metrification andhence is in Canadian yard/pound measures. Onehundred and five healthy Douglas-fir trees, selectedto cover the observed range of dbh (2.5 - 32.0 em).
were felled or climbed and measured for dob at2.54-cm taper steps from the butt. Segment volumeswere calculated using Newton's formula (Chapmanand Meyer, 1949), A regression using dbh and heightas independent variables and measured volume asthe dependent variable was fitted, giving the followingvolume equation:
log V = -2.48036 + 1.95882 log D +0.971352log H
where: V = volume in cu ftD = dbhob in inchesH = total height in It
2.3 Measurements on an individual tree basisR2 = 0.999 SEE = 0.031 eu It; No. of obser
vations= 105
Measurements, taken on an individual treebasis, are designed to provide yearly trends in incre·ment, estimates of volume and form changes andto provide a data base for related investigations.
Individual trees (volume sample trees), 231and 233 for the 1971 and 1972 plots. respectively.
were selected 3 years after treatment on the basis ofinitial dbh and competitive position in the stand
This equation was used to determine individual treevolumes at the time of establishment. However, inthe case of the 1972 plots where tree heights werenot available, it was necessary to estimate initialtree height from data collected on the thinned 1972plot trees.
The regression selected for estimating initialtree height was:
7Height" -14.9985 - 3.27337 0 +
31.152115where 0 " dbhob
where: H = Initial height in feetThis relationship was derived for Douglas-fir,
western red cedar, western hemlock, balsam, western
white pine and lodgepole pine (Appendix III).0= Initial dbhob in inches
R2 = 0.918, SEE" 2.90 It; No. olobservations" 1636
2.5 Data recorded for all plot trees
The data recorded are as follows:
Height increment by treatment was estimatedfrom "1971 plot data. This estimate of height incre
ment was based on regression analysis of heightincrement against initial height, initial dbh, and dbh
increment. The regression form selected was:
i) plot and tree number
ij) X and Y coordinatesiii) species
iv) treatment
Treatment codes used are;
where a,b, ,b2,b3,b4 and b5 are regressioncoefficients
o = Initial dbhob in inches.
/). 0 = Dbh increment in inches.
Ii H = Height increment in feet.H = Initial height in feet.
Regressions were derived for each of the 9
treatments in the 1971 plot series and applied to thecorresponding treatments for the 1972 plot series.The equations derived are given in Appendix II.
TOFO - CONTROL - No thinning, no fertili-
zation
TOF 1 - No thinning, 224 kg Nlha (urea)
TOF2- No thinning, 448 kg Nlha (urea)
T 1FO - Intermediate thinning, no fertilizer
T1F 1 - Intermediate thinning, 224 kg Nlha(urea)
T1 F2- Intermed iate thinning, 448 kg Nlha(urea)
T 2FO - Heavy thinning, no fertilizer
Diameter class Class mid point (cm) Range cm
Diameter classes used in the analyses are asfollows:
T2F1 - Heavy thinning, 224 kg Nlha (urea)
T 2F2 - Heavy thinning, 448 kg Nlha (urea)
2.50·4.995.00 - 7.497.50 - 9.99
10.00 - 12.4912.50 - 14.9915.00 - 17.49
17.50 - 19.99
3.756.258.75
11.2513.7516.25
18.75
1234
567
v) mortality index records thinned trees,mortality, damage, or disease
vi) CSI at time of establishment, after thinning
and thereafter at 3-year intervals
vii) total height at establishment and thereafter
at 3-year intervalsviii) dbhob at treatment, annually for 3 years
and thereafter at 3-year intervals
To determine tree volume 3 years after treat·ment, it was decided that if no significant change inform quat ient occurred between treatments, the
initial condition volume equation would be used.
The data used to test this hypothesis were taken fromthe detailed measurement of the volume sample treesfor both the 1971 and 1972 plots. Analysis of variance
and paired t tests failed to show any significantdifferences between form quotients for the different
treatments. Consequently, the initial volume equationwas applied to estimate total tree volume 3 years
after treatment.
Merchantab Ie Factor" a+b lID + b2loge 0 + b30
Merchantable tree volume (close utilization)was derived from merchantable volume curves devel·
oped by the B.C. Forest Service (unpublished).Regressions were fitted to these curves to facilitate
determination of merchantable volume values "for
each individual tree. This procedure avoids the
unrealistic merchantable volume increases that occur
when dbh class values are applied to individual
trees, especially where stands are just reaching mer·chantable sizes. Form of the regressions used was;
B
ix) gross and merchantable volume at establishment and thereafter at 3-year intervals
xl height to base of live CrOwn at establishment
xi) stem maps before thinning, after thinningand every 3 years thereafter
3.0 3 - year growthresponse
and 3).
3.1 Volumes per hectare produced in the first3 years following treatment
The data presented in this section are basedon the mean treatment response per plot (4 replica·tions per treatment) converted to a per hectare basis.
Gross Volume
Gross volume (G. Vol) and merchantablevolume (M. Vol) per hectare are reported along withcumulative increment for dbh and height (Figs. 1,2
The 3-year gross volume and the percent gainor loss in 3-year increment compared to control aregiven in Fig. 1a. The maximum 3-year gross volumeincrement of 70.67 m3/ha occurred with the TOF2
a) Gross volume
'00
:3 YR. GROSS VOL.GROWTH FOLLOWINGTREATMENT
GROSS VOL.AT TREATMENT
} TREATMENTS--T2-
Fa FI F2
43
b-il3+-~"...-+;,<,/--~.••.••.3.••.6,.-- ~"--~ _-+-_~_i_iA_WT_~_~E_R~_~_HL_L_~_~L_'N_Gm MERCH.VOLAT TREATMENT
--T,-
Fa FJ F2
8058l\< 54
--To-Fa F1 F2
o
50
50
50
c~,~
E
w 100
":::>..J0>
'50
50
o
b) Merchantable volume- percentage gain or loss over control
Figure 1. Gross and merchantable volume per hectare by treatments.
Figure 2. Cumulativedbh increment by treatments for dbh class 4.
'.0
~I
2.0...z~
'"~'"0;!;
or~
0
~
>;:::~J 1.0"'""0
'.0
9
./"-'./" ,"0'.. ....-::.,~ ._..... CO""'.' -:;:;: ....
~.:.. ,
;;;;.::::',:::~
2
YEARS SINCE TREATMENT
TREATMENTS
... ToFo
Figure 3. Cumulativeheight increment by treat·ments for dbh class 4.
2.0
1.0
TREATMENTS
I 2
YEARS SINCE TREATMENT
10
4.0 Analysis ofgrowth response ofindividual trees
The PAl for control trees is compared tothat of treated trees which had the same initial dbh(Figs. 4 through 7). Within treatments, trees of differing initial dbh are compared to provide someinsight into changes in stand dynamics associatedwith treatment.
Examination of the gain in dbh incrementover that of the control indicates that increasingthe levels of both fertilization and thinning resultedin increased increment (Fig. 4 and Appendix VII).In general, the greatest response for each fertilizationlevel was associated with the heavy thinning treatments.
In this analysis, individual tree PeriodicAnnual increment (PAl) Of is used throughout.Comparison of the growth responses of individualtrees between and within treatments provides a goodbasis for the evaluation of response to fertilizationand thinning. It provides for a better understanding ofplot response data and is input data for stand models.To make the comparisons, regressions using healthyDouglas-fir trees were fitted for dbh, ba, heightand gross volume increment against initial dbh(Appendix V). These equations were solved for 6.25,8.75. 11.25 and 13.75 em initial dbh, the midpointsof the dbh classes 2 through 5. Insufficient dataprecluded use of dbh classes 1 and 6 through 11.
Dbh increment (em/a)4.1
treatment, and the smallest increment of 22.20m 3/haoccurred with the T2FO treatment (Appendix IV).Fertilization has given a marked increase in GrossVolume increment. As might be expected, thinningalone has reduced the Gross Volume but this incre·ment has accrued on a smaller number of largertrees. Fertilization with thinning has offset the volumeincrement reduction that resulted from thinning.
Merchantable Volume
Fertilization increased growth at all thinninglevels (Fig. 1bl. Thinning alone reduced the responsedue to the reduction in number of trees. Fertilizationof intermediate thinnings compensated for the increment reduction associated with thinning and resultedin increments similar to the unthinned treatments.Fertilization of heavy thinning treatments resulted ina substantial increase in increment that more· thancompensated for the thinning effect.
Initial stand differences (Appendix VI andFig. 1) have profound and confounding effects ongrowth response. For example, the marked differencein number of trees and dbh distribution in theunthinned plots explains the higher initial volumesin the TOFO (Control) as compared to the TOF2treatment. Also, the higher initial merchantablevolume of the TOF 1 treatment results from thepresence of a few larger trees (see Table 11.
The maximum 3-year merchantable volumeincrement of 58.81 m3/ha occurred in the T lF2treatment, and the smallest increment of 20.76 m3/haoccurred with the T2FO treatment (Appendix IVI.
3.2 Cumulative increment for dbh and height
Graphs of cumulative dbh and height increment against years since treatment are given fordbh class 4 to provide insight into annual changesin response (Figs. 2 and 3). These data were takenfrom the volume sample trees and hence do notcoincide exactly with individual tree response determined by regression (Figs. 4 and 5).
Comparisons of response to fertilization andthinning indicate a positive treatment interaction.For example, in dbh class 4, the dbh incrementfor control (TOFOI was 0.39 em. The gain abovecontrol for heavy fertilization alone (TOF2) was 0.38cm; for heavy thinning alone (T2FO) was 0.25 cm,and for heavy fertilization and thinning combined(T2F2) was 0.83, indicating a positive interactionof 0.20 em.
The similarity of the dbh growth trends forthe T2F2 and T2F, treatments after 3 years isworthy of note, and future trends for these treatments will be of considerable interest. 0 ivergenceof height increment between fertilized and unfertilized treatments in these early measurements isvery distinct and will be monitored closely in future.
In all cases, total dbh increment for a giventreatment increased with increasing initial dbh(Appendix VII). When examining gain over controlincrement for a given treatment, the small dbh
* For the first 3 years following treatment.
11
TREATMENTS
----T,---
"
----T,----
2 3 4 5 2 :3 .. 5 2 3 4 5 , , , , 2 3 4 5 , , , , , , , , , , , , , , 4 ,INITIAL DBH CLASS
Figure 4. PAl for dbh by dbh classes and treatments. (em/a)
TREATMENTS
T,
'0 " "
0
00
00 0 :=
:~ 0
0
0 0
" " " 0
0 0
0
~ ~
0
0
::0
0
000000
:;
~~
zou
~o••
*~z8~
"•,8x~
~o
rc
I? ~: JI~0
CONTROL I~ 0
c- o t/.
~L 0 L L ,
00
"" 00
0 000
-----TO-----
-1+~
zou
~
"•,8x~
~•o
"~~
zou~
>oo•
....
2 3 4 52 3 4 52 3 4 52 3 4 5
"
~ 0
~ ~0
~
~~
0.!:<
L~::
~0t::' 00
0
'" 0~
2 3 4 5
INITIAL OBH CLASS
2 3 4 5
----- T, -----
""
2 3 4 5
"
2 3 4 5
'0
2 :3 4 5
'0
"
0 '0,N
~
'"'" ,~
0
,
00
Figure 5. PAl for ba by dbh classes and treatments. (cm2 /al
Note: - Total increment = Growth equal to control + Gain above control.
12
TREATMENTS
----TO---- -----T, ----- T,-----
~0Zovw>g•
2 3 4 5
F,
2 3 4 :5
FO
2 :3 4 :52 :3 4 5
F,
2 :3 4 5
FO
2 :3 4 52 3 -4 5
::
, , ,- ,:::
, , ., :::: :: : :
: :: : :: : :: :: ::::
:: :::: :
:: ::
F,
2 :3 4 :>2 :3 4 ~
FO0'
0'0,
CONTROLE
° ~0-~ :'" :W ::~ 0':
:
0' :
INITIAL OBH CLASS , ,t_~ GROWTH LESS THAN CONTROL
Figure 6. PAl for height by dbh classes and treatments.(m/al
TREATMENTS
To T, T,
FO F, F, FO F, F, Fo F, F2
"00"
• Gain above control as a percentage of control growth.
"0 179
92 ::.. : "0'0 '" 2~0
• '"~., z
~~ ~:: 08 ~:: v
: 78
'" '" "o~ : ww : >~ 00' " 97 :;
:: : :: 09' : ~
~
" :: 23 '50 •~
0.48 :: :: IF ~
:
t> r 7 rCONTROL 46 .
~" [(0:-~ ;;: : ::~ °
~0 Ii L : L L :: L ::~ ::'" :: :
: ::a :: : 0-
: z~ :: : : : 0.00' :: v
:: : 00-
"•,0
.010 w~0-•, , , , 2 , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , 0z0
INITIAL aSH CLASS
Figure 7. PAl for gross volume by dbh classes and treatments. (m3/a)
Note: . Total increment = Growth equal to control + Gain above control.
classes occasionally exhibit a greater gain than thelarge dbh classes (i.e., T lFOI and with little or nodifference between classes 4 and 5.
13
(T 2F2) was 0.0127 m3, indicating a positive interaction of 0.0047 m3.
Sa response is essentially identical to dbhresponse (Fig. 5 and Appendix VillI. The onlymarked difference is that there is a more consistentincrease in ba gain with increasing initial dbh. Treat·ment responses for dbh class 4 are as follows: Saincrement for control 1TOFOI was 7.19 cm2 Thegain above control for heavy fertilization alone (TOF2)was 7.66 cm 2; for heavy thinning alone (T2FOI was4.95 cm2, and for heavy fertilization and heavythinning oombined was 17.75 cm2, indicating apositive treatment interaction of 5.14 cm 2.
4.2
4.3
Sa increment (cm 2/a)
Height increment (m/a)
Total volume increment and increment gainabove control increased markedly for a given treatment with increasing initial tree size. However, it isinteresting to note that gain above control expressedas a percentage of control growth for a given dbhclass is inversely related to tree size, as shown by thepercentage values in Fig. 7.
5.0 Methods ofevaluating treatment response on aper hectare basis
Height increment response differs markedlyfrom dbh and ba response. The most strikingfeature was the decrease in height increment associatedwith increasing thinning intensity when no fertilizerwas added. This is commonly termed "thinning shock"and is well illustrated in Fig. 6.
Fig. 6 and Appendix IX show that:
1) for those treatments having no fertilizerapplication, the periodic annual incrementin height was less than that of the control,and decreased as thinning intensity increased
(T 1FO, T 2FOI2) for those treatments having no thinning,
the periodic annual increment in heightincreased with fertilization (TOF1' TOF21.
3) fertilization reduces the degree of thinningshock; the heavier the fertilizer applica·tion, the less the shock.
4.4 Gross volume increment (m3/a)
The gain in gross volume increment over thatof the control provides the measure of the effectof fertilization and thinning. Increasing levels ofboth fertilization and thinning increased volume gainfor all dbh classes (Fig. 7 and Appendix XI.
Comparison of the volume increment responseindicates a positive treatment interaction. Forexample, in dbh class 4, volume increment for control(TOFOI was 0.0071 m3. Gain above control for heavy
fertilization alone (T OF21 was 0.0062 m3; for heavythinning alone (T2F01 was 0.001S m3; and forheavy fertilization and heavy thinning combined
How best to evaluate treatment response ona per hectare basis is still an open question. The verymarked variation in the response of trees of differentdbh class within treatments (F ig. 7) points up theimportance of tree frequency distribution by dbhclass when per hectare response is being considered.
Gross differences in tree frequency distribution result from the removal of trees in thinning.Other less obvious but important tree frequencydistribution differences within thinning treatmentsresult from variations in site, initial stand conditionand mortality. The effect of the tree frequencydistribution differences on the evaluation of treatment response (fha) can be demonstrated, ingeneral, by comparing the actual 3-year volumeincrement given in Fig. 1 with the results of theindividual tree PAl for gross volume in Fig. 7.In Fig. 1, thinning within fertilization treatmentsshows a loss in 3·year volume increment, whereasin Fig. 7, a net gain in gross volume increment isshown. The large differences in tree frequencydistribution created by the removal of trees inthinning (Appendix VI) mask the treatmentresponse on a per hectare basis. Therefore, toevaluate treatment response, these important treefrequency distribution differences must be accountedfor.
Two approaches are examined: 1) standstructure analysis, and 2) crop tree analysis.
Stand structure analysis was used on theShawnigan Lake data to evaluate gross volumeresponse to treatment. The concept was describedby the Regional Forest Nutrition Research Project(Anon., 1975).
5.1 Stand structure analysis
14
mined (3) to the dbh frequency distri·
but ions for each treatment (2)5) the difference between the total gross
volume increment and the gross volumeincrement for control image (41 was taken
to represent treatment response6) treatment response was then expressed as
a percentage of the control image
Treatment responses were calculated as
follows:
1) total gross volume increment was determined for each treatment
2) dbh frequency distributions were determined for each treatment
3) gross volume increments were determinedfor midpoints of each dbh class for controltreatment
4) a 'control image' was created by applyingcontrol gross volume increments deter-
Regression equations on healthy Douglas-fir(Appendix V) were used to define the control andtreatment increment values for dbh classes 1-7. Classes8 through 11 were not included because, in the initialstand condition, these dbh classes were not represented in all treatments. Using the tree frequency distribution for the healthy Douglas-fir as they exist foreach treatment, the percentage of gain or loss in grossvolume increment by treatment was calculated and isgiven in Fig. 8. Results from stand structure analysis
can be compared to Fig. 8.
FO10
5
0,0~,
0'"E
w
"::>-'~ 5
'"'"0a:
'"10..
"-
15
--TO-
Fe F1 F2
50
TREATMENTS
---T,--
Fe F1 F2
46
'4-2.....; I
•••••• i::t:.
---T2---
F1 F2
• Percentage gain or loss over control.
GAIN ABOVECONTROL
GROWTH EaUALTO CONTROL
, ,~ _ ~ GROWTH LESS THAN CONTROL
Figure 8. Calculated PAl for gross volume of healthy Douglas-fir on a per hectare basis.
15
The concept was applied using three sets offrequency distributions by dbh class as follows:
ments.
1) Actual tree frequency distributions
1) The actual tree frequency distributionsby treatments as they occurred (AppendixXla).
2) The mean tree frequency distribution foreach thinning level (Appendix Xl b).
3) A hypothetical tree frequency distribution equivalent to the individual plotthat had the smallest number of treesafter thinning (Appendix X1c).
The last two were tested in order to removestand structure differences among thinning treat-
In this analysis, comparisons were made usingthe actual tree frequency distributions as theyoccurred.
Figure 9 shows the treatment response (volumeincrement gain above control image) determined bystand structure analysis. This method of analysisgives a good estimation of both fertilization andthinning response. However, evaluation of the resultsis still confounded by different numbers of trees,both within and between thinning levels.
TREATMENTS
--TO--
Fa F, F2
--T2-
Fo F1 F2
1591
178
II.
.. Treatment response as a percentage of control image growth.15
10
c,c
5~,'"E TREATMENT
w 10 RESPONSE
'"::> 0~~~.J
0> ,,,,, CONTROL
U> ~(IMAGE GROWTH
U>0 :~:a:: ,'" 5 ,,,,
'" {a. ,.,
:::::;,
10,,,,,
Figure 9. Treatment response by stand structure analysis using actual tree frequencydistributions.
16
2) Mean tree frequency distribution for eachthinning level
was applied to a hypothetical distribution whichcoincided with that of the individual plot having theleast number of trees (F ig. 11).
The use of mean tree frequency distributioncalculated for each thinning level removes differencesand gives a better basis for the evaluation of fenilizereffects within thinning levels (Fig. 10). This treatmentof the data made little or no difference to the per·centage calculations. However, it did affect treatmentresponse; e.g. positive adjustment of the controlimage for the TOF2 treatment caused an increase inthe treatment response.
Use of the hypothetical distribution has theadvantage of removing stand structure differencesassociated with thinning effects and initial standconditions. The order of treatment response dupli·cates that found for individual tree gross volumegain (Fig. 7). The order of response, from highest
to lowest, was as follows: T2F2' T2Fl' T1F2' TOF2'T 1F1, TOF 1, T2FO' T1FO and TOFO'
3) Hypothetical tree frequency distribution
To oompare results of both thinning and fer·tilization on the same basis, stand structure analysis
While the stand structure analysis providesa good base for evaluating response, it is somewhatlimited in that it is not possible to include the largertrees because they do not exist in all treatments.
TREATMENTS
--TO--
Fe FI F2
--T,
Fo F,
--T2--
Fe Fl F2
1591
176
• Treatment response as a percentage of control image growth.
II.
15
10
c
"c~ 5",.,E
TREATMENTw RESPONSE
":::> 0...J0 CONTROL>U) IMAGE GROWTHU)
0a:
5'";;"-
10
Figure 10. Treatment response by stand structure analysis using mean tree frequency distribution for each thinning level.
17
TREATMENTS
--TO-
Fa F1 F2 FO
--T2-
Fa F1 F2
.. Treatment response as a percentage of control image growth.'0
c,C
L,'" 5E
w:E:::>--'0> 0UlUl0a:
'".. 5a.
'08
89
-'o'"I-Zou
17'
TREATMENTRESPONSE
CONTROLIMAGE GROWTH
Figure 11. Treatment response by stand structure analYsis using hypothetical tree frequencydistribution.
GROWTH EQUALTO CONTROL
TREATMENTRESPONSE
GROWTH EQUALTO CONTROL
TREATMENTRESPONSE
'BB
".
TZFZ - TREATMENTS
A
AAA
39
itA A
'0.
A
A
A
618 LARGEST TREES I ho
395 LARGEST TREES I ha
A
• •
11A A
110
AAA
CONTROL
CONTROl
PA
,
,
0
0,0 ,~,~
E
w:>
'0"-'0>
'"'"0'" ,'"....
0
A - ACTUAL
B - ADJUSTED .. Treatment response as a percentage of control.
Figure 12. Actual and adjusted treatment response by covariance analysis using the 395and 618 largest trees per hectare.
18
Table 1 - Initial mean dbh and height for the 395 and 618 largest trees per hectare.
Treatment
TOFO TOF 1 TOF2 T1 FO T 1F1 T 1F2 T2 FO T2F1 T2F2 GeneralMean
lal 395 largest trees/ha.
Initialdbh(eml 13.40 14.76 12.53 13.49 13.50 13.19 12.56 12.40 12.65 13.16
Initialheight (m) 12.03 12.30 11.02 11.92 11.62 11.40 10.99 11.31 11.11 11.52
(b) 618 largest trees/ha
Initialdbh (em) 12.74 13.67 11.93 12.70 12.76 12.48 11.59 11.62 11.71 12.36
Initialheight (ml 11.77 11.83 10.70 11.54 11.36 11.03 10.60 10.98 10.67 11.16
Table 2· Table of significance for fertilization, thinning and interaction using the 395 largest trees per
hectare
395 largest trees/ha
618 largest trees/ha
Dbh Sa Height Volume
Thinning •• • ••• ns •••Fertilization *... ••• ••• •••Interaction •• * • ••• •
Thinning ••• ••• ns •••Fertilization ••• ••• ••• •••Interaction • • •• ns
where ,.. = significant at the 5 percent level
** = significant at the 1 percent level,..,..,.. = sign ificant at the 0.1 percent level
and os = non significant.
5.2 Crop tree analysis
19
using:
The primary management objective in ferti·lizing and thinning is to speed up the growth of thecrop trees. Therefore, evaluation of treatment responseof the potential crop trees would seem to be a logicalanalytical approach that would probably appeal topracticing foresters and that would appear to havesome distinct advantages, e.g.:
1) the analysis is not complicated by themany small tfees that will have little orno merchantable value.
2) it eliminates the problems associatedwith the variation in stand structure.
3) the analysis is based on trees that have ahigh probability of being harvested.
The 395 and 618 largest trees per hectare(160 and 250 trees per acre, respectively) wereselected as representing the lower and upper limitsof the range of density of potential crop trees (commercial thinning and final crop) for managed standson sites similar to Shawnigan Lake. The response issimilar to that shown for individual trees and standstructure, except where the trees are considerablysmaller or larger than the general mean T 2FO andTOF1 treatments (Table 1, Fig. 12),
The difference in initial mean dbh and heightnecessitated the use of covariance analysis to evaluatethe differences in response to fertilization and thinning. The analysis was based on individual trees,using initial dbh and initial height as covariates.
The results of the analyses (Fig. 12 andAppendix XII) generally confirm the results obtainedfrom the individual tree and stand structure analyses.
The parameters showing statistical significanceover control for fertilization and thinning and theirinteraction are given in Table 2.
6.0 Comparison ofanalyticalapproaches
The response of Douglas-fir at ShawniganLake to fertilization and thinning has been evaluated
1) response on hectare basis; 2) growthresponse of individual trees; 3) stand structureanalysis, and 4) crop tree analysis.
With the exception of the response on ahectare basis, the analyses gave generally similarresults. However, we feel that all of the approacheshave application, albeit for different purposes. Someof the potentials and limitations of the approachesare listed below:
1) Response on a Hectare Basis
al Potentials
i) provides a real measure of totalvolume and volume increment.
bl Limitations
i) growth response is confounded bydiffering number of stems withindbh classes, especially among thinning treatments.
2) Growth Response of Individual Trees
a) Potentials
i) provides a basis for elucidatingstand dynamics and evaluating theeffects of competition.
H) allows comparison of growth response of essentially identical individual trees.
iii) provides an excellent basis forinput into stand models.
b) Limitations
j) does not provide information ontotal stand response (area response)
unless used in conjunction with thestand table, as in stand structureanalysis.
3) Stand Structure Analysis
a) Potentials
i) has the greatest potential for deter
mining response to thinning and fert
lization in the mid-range diameters.
iil is easily adaptable for application indeveloping managed stand tables.
iii) provides an excellent base forevaluating fertilization effects within (or inthe absence of) thinning treatments.
b) Limitations
i) it is of restricted value at the upperand lower diameter limits becauseof few or missing trees.
4) Crop Trees Analysis
a) Potentials
il has the g-eatest potential appli·cation for forest management, webelieve, as it relates to that partof the stand that is of the greatesteconomic importance.
b) Limitations
i) ignores the large component ofsmall trees.
7.0 Summary
The principal purpose of this paper is topresent the 3-year fertilization and thinning responseof a young stand of Douglas-fir at Shawnigan Lakeand to compare analytical approaches to the evaluation of response.
The study area and experimental layout aredescribed briefly and a detailed description of thedata base, including the units of measurement,measurement on a plot basis, measurement on anindividual tree basis and a description of the datacurrently being recorded, is given.
Regression equations are derived to estimatetotal tree volume and merchantable volume andinitial height and dbh, ba, height and gross volumeincrement by treatments. Analysis of form quotientshowed no significant differences between treatments.
3-year-treatment response is reported interms of:
20
1) volume increment (gross and merchantable)on a hectare basis
2) cumulative increment for dbh and height3) growth response of individual trees (dbh,
ba, height and volume)4) stand structure analysis using three dbh
frequency distributions5) crop tree response for the 395 and 618
largest trees per hectare (160 and 250largest trees per acre).
1) Evaluation of treatment response, usingvolume increment on a per hectare basis indicatedthat fertilization within thinning levels resulted inincreased increment, while thinning caused a reduction in increment. The reduction in response associated with thinning is attributable to fewer numbersof trees on the thinned plots. The different numbersof trees within thinning treatments distorted themagnitude of response to fertilization. The use ofvolume response on a per hectare basis is thoughtto be unsatisfactory for determining both the magnitude and order of response, because of differencesin initial stand condition and differences in the treefrequency distributions by dbh class.
2) Examination of annual dbh and heightincrement trends provided some interesting indications of response. Obh increment responded wellto both fertilization and thinning over the 3-yearperiod and appears to be maintaining the differential rates of increment. The similarity of growthresponse to the T2F2 and T 2F 1 treatments shouldbe of special interest to the forest manager becauseof the high cost of fertilizer. The differential ratesof height increment also appear to be continuing.
3) Both fertilization and thinning resultedin increased PAl for dbh, ba and volume on individ·ual trees. Fertilization caused an increase in heightincrement regardless of thinning level, whileincreased levels of thinning reduced height incre·ment. While the analysis of individual tree responsecannot be used directly in determining response on ahectare basis, it provides a good basis for comparisonof treatment response by diameter classes and hasconsiderable promise for application in modelling.
4) The stand structure approach providedan excellent base for determining response to fertilization and thinning in the mid-range diameters,but has limited application for projecting final cropvolumes because it is not possible to include the very
large trees.
5) The crop tree approach, which evaluatestreatment response on the potential crop trees, isprobably the most appealing to practicing foresters.However, it ignores a large component of small trees.
On the basis of the analyses conducted, itwould appear that the magnitude of response recorded for fertilization and thinning depends to a largedegree on the type of analysis used. Our intent hasbeen to present a number of differing proceduresand to solicit reader response to their application.
21
9.0 REFERENCES
Anon, 1975. Washington State University, Seattle.College of Forest Resources, Regional forestnutrition research project. Biennial Report1972-74.
Arney, J.D. 1973. Tables for quantifying competitivestress on individual trees. Can. Dept. Environ.,Can. For. Serv., Pac. For. Res. Centre, Victoria.Information Rept_ BC-X-7B_ 15 pp_
Chapman, H.H_, and W.H. Meyer. 1949_ ForestMensuration. McGraw-HilI. New Yrok. 1949.
The authors thank John F. Dronzek for histechnical assistance in the field, Jack Rudd for pro·gramming assistance, Donald W. Whitney for deri·vation of merchantable volume factors, and JohnC. Wiens for the illustration of this report.
8.0 ACKNOWLEDGMENTS
Crown, M., Brett, C.P. et al. 1975. Fertilization andthinning effects on a Douglas-fir ecosystemat Shawnigan Lake: An establishment report.Canadian Forestry Service, Pacific ForestResearch Centre. Victoria, B.C. ReportBC-X-l10, January 1975_
Miller, R.E., and L.V. Pienaar. 1973. Seven-yearresponse of 35·year-old Douglas-fir to nitrogenfertilizer_ USDA For. Serv. Res. Pap. PNW-165,24 p., illus. Pacific Northwest Forest andRange Experiment Station, Portland, Oregon.
22
10.0 Appendices
Appendix I. Plot Measurement Schedule
Date to be Kind of measurement
measured 1971 plots 1972 plots
Spring '76 3
Fall '76 1,3& 4 2&5
Fall '77 2&5 1,3& 4
Fall '78 2&5 2 & 5
Fall '79 1,3& 4 2 & 5
Fall '80 2&5 1,3& 4
Fall '81 2&5 2&5
Fall '82 1,3& 4 2&5
Fall '83 2&5 1,3& 4
Fall '84 2&5 2& 5
Fall '85 1,3& 4 2& 5
Fall '86 1,3& 4
Kind of measurement:
1 = Dbh all trees in the plots.
2 = Dbh all volume sample trees.
3 = Original height or height every 3 years on all trees in the plots.
4 = Volume sample tree measurement (dbh, dab at taper steps, and height).
5 = Dbh all trees used in study PC·23·006 not measured in 1 or 2.
Ap
pen
dix
II.
Reg
ress
ion
equ
atio
ns
for
esti
mat
ing
3-ye
arh
eig
ht
incr
emen
t(b
,H)
by
trea
tmen
t
R2
SE
Elm
las
s
TOFO
/lH
=-1
.97
48
2+
2.47
792
D-.
55
14
74
D2
+.3
1257
9E-Q
1D
3+
5.22
529/
1D+
.495
936E
-01
H0.
866
0.70
235
7
T1F
OIl
H=
3.97
355
-.8
77
77
4D
+.3
7219
5D
2-.
30
21
47
E-0
1D
3+
3.22
7511
D-
.597
534E
-01
H0.
607
0.90
915
4
T2
F Oll
H=
-2.0
37
94
+.9
2164
5D
-.1
03
13
D2
+.2
0602
7E-Q
2D
3+3
.619
1311
D+
.192
91E
-Q1
H0.
705
0.71
972
TOF
1II
H=
-3.9
02
45
+4.
5855
5D
-.9
67
55
8D
2+
.604
633E
-01
D3
+4.7
0053
11D
+.2
60
4E
-01
H0.
899
0.80
226
7
T1F
1ll
H=
-5.7
05
65
+7.
1371
7D
-1.
5805
4D
2+
.115
326
D3
+2.
4503
711
D-.
63
57
79
E-Q
2H
0.68
90.
985
139
'"w
T2
F1
llH
=28
.518
5-
19.0
712
D+
5.05
678
D2
-.4
09
21
8D
3+2
.046
811D
..10
6627
H0.
660
1.06
071
TO
F2ll
H=
-5.0
03
03
+7.
1718
9D
-1.9
91
35
D2
+.1
70
11
D3
+5.
2419
411D
+.8
86
62
E-0
2H
0.84
41.
078
301
T1
F2
IIH
=-2
.88
09
+6.
59D
-1.
3041
5D
2+
.883
537E
-01
D3
+2.
1791
311D
-.9
96
32
9E
-01
H0.
706
0.90
116
1
T2
F2
llH
=1
5.6
89
3-7
.29
26
5D
+1
.71
63
8D
2_
.12
80
68
D3
+4.
0161
411D
-.1
20
22
H0.
382
1.39
669
Wh
ere
0=
Init
ial
db
ho
bin
inch
es
60
=3-
year
db
hin
crem
ent
inin
ches
H=
init
ial
hei
gh
tin
feet
6H=
3·ye
arhe
ight
incr
emen
tin
feet
Ap
pen
dix
III.
Mer
chan
tabl
eV
olum
eF
acto
rE
quat
ions
Do
ug
las-
fir:
Wes
tern
Red
Ced
ar:
Wes
tern
Hem
lock
:
Bal
sam
:
Wes
tern
Whi
teP
ine:
Lo
dg
epo
leP
ine:
R2
SEE
a8
S
MV
F=
5.0
38
15
-11
.75
06
/0-1
.45
21
810
9,,0
+.4
295E
-QlD
0.99
60.
003
30
MV
F=
4.1
40
84
-9.2
37
64
/0-1
.48
92
310
geO
+.3
32
8E
-Q1
00.
992
0.00
330
MV
F=
5.0
99
95
-11
.60
13
/0-1
.48
92
41
09
00
+.4
470E
-OlD
0.99
00.
004
30
MV
F=
2.0
10
59
-3.8
43
46
/0-0
.33
03
110
900
+0.
7052
E-Q
201.
000
030
MV
F=
5.0
75
92
-11
.56
85
/0-1
.47
52
010
geO
+0.
4386
E-O
lD0.
990
0.00
430
MV
F=
4.9
10
80
-11
.07
79
/0-1
.41
70
610
geO
+0
.41
83
2E
-QlD
0.98
90.
003
30
whe
re:
MV
F=
Mer
chan
tabl
eV
olum
eF
acto
r'" ""
0=
dbh
inin
ches
Fo
rd
bh
valu
esg
reat
erth
an3
0in
ches
(75
cm),
the
abov
ere
lati
on
ship
sd
on
ot
app
ly
Ap
pen
dix
IV.
Act
ual
gros
san
dm
erch
anta
ble
lJol
ume
bytr
eatm
ents
.
Tre
atm
ents
TOFO
TO
FlT
OF2
T1
F OT
1F
1T
lF2
T2
F OT
2F
lT
2F
2
1.G
ross
volu
mes
(G.
Vol
).
(al
G.
Vol
.ju
staf
ter
trea
tmen
t11
971
&19
721
(m3 /
plot
)5.
675.
284.
013.
483.
413.
361.
811.
931.
84
(197
1&
19
72
llm
3 /ha
)14
0.11
130.
4799
.09
85.9
984
.26
83.0
244
.73
47.6
945
.47
Ibl
G.
Vol
.3
yrs
afte
rtr
eatm
ent
1197
3&
1974
)(m
3 /pl
ot)
7.66
7.96
6.87
4.90
5.74
6.17
2.71
3.53
3.82
1197
3&
1974
l1m
i3/h
al18
9.28
196.
7016
9.76
121.
0814
1.84
152.
4666
.97
87.2
394
.39
lei
3·yr
.G
.V
ol.
Incr
emen
t(m
3 /ha
l49
.17
66.2
370
.67
35.0
957
.58
69.4
422
.24
39.5
448
.92
Idl
G.
Vol
.PA
lm
3 /ha
/a"
16.3
922
.08
23.5
611
.70
19.1
923
.15
7.41
13.1
816
.31
v-
(e)
3·yr
G.
Vol
Incr
emen
tex
pres
sed
asa
%o
fIn
itial
G.
Vol
.35
5171
4168
8450
83
108
2.M
erch
anta
ble
volu
me
1M.
vall
.
lal
M.
Vol
.ju
staf
ter
trea
tmen
t(1
971
&19
721
(m3 /
plot
l1.
702.
051.
091.
371.
421.
200.
750.
820.
80
(197
1&
1972
)Im
3 /ha
l42
.01
50.6
626
.93
33.8
535
.09
29.6
518
.53
20.2
619
.77
Ibl
M.
Vol
.3
yrs
afte
rtr
eatm
ent
1197
3&
1974
)Im
3 /pl
otl
3.02
4.13
3.12
2.52
3.38
3.58
1.59
2.37
2.69
(197
3&
1974
)(m
3 /ha
)74
.63
102.
0577
.10
62.2
783
.52
88.4
639
.29
58.5
666
.47
lei
3-yr
.M
.V
ol.
Incr
emen
tIm
3 /ha
l32
.62
51.3
950
.17
28.4
248
.43
58.8
120
.76
38.3
046
.70
(d)
M.
Vol
.PA
lm
3 /ha
/a10
.87
17.1
316
.72
9.47
16.1
419
.60
6.92
12.7
715
.57
(e)
3·yr
M.
Vol
incr
emen
tex
pres
sed
asa
%at
,~:
..:.
.tFI
ll"
.....1
'0,n
,,o
c0
''0
0,n
o""
,no
Ap
pe
nd
ixV
.R
egre
ssio
neq
uat
ion
sb
ytr
eatm
ents
for
per
iod
ican
nual
incr
emen
t*(d
bh
,ba
,he
ight
and
gros
svo
lum
e).
Tre
atm
ent
1-
No
thin
nin
g,
nofe
rtili
zer
-co
ntr
ol
(TO
FOI
dbh
incr
emen
t=
-.9
74
14
6E
-Q1
+.5
7727
6E-Q
10
+.7
1409
9E-Q
20
2-.
21
00
21
E-Q
30
3
bain
crem
ent
:1
.97
16
3-1
.33
57
50
+.3
1209
30
2-
.34
30
55
E-0
20
3
ht
incr
emen
t=
-2.1
76
95
-.2
22
98
30
+1
.85
85
9/0
g.vo
l.in
crem
ent
:.2
07
58
8E
-02
-.1
40
34
8E
-02
0+
.274
674E
-Q3
02
+.1
5246
4E-Q
60
3
Tre
atm
ent
2·
Inte
rmed
iate
thin
ning
,no
fert
iliz
erIT
1FO
)
R2
=0.
910
R2
=0.
962
R2
=0.
899
R2
=0.
976
SEE
=0.
170
cm
SEE
=2.
778
cm2
SE
E=
0.1
88
m
SEE
=0.
0023
8m
3
db
hin
crem
ent
=.2
3600
9+
.60
58
29
E-0
10
+.6
64
38
5E
-02
02
-.2
3991
4E-Q
30
3
bain
crem
ent
:2.
8584
1-1
.14
99
20
+.3
7026
60
2-.
70
21
78
E-0
20
3
htin
crem
ent
=.1
3318
7+
.244
382
E-0
10
+.2
72
32
3/0
g.vo
l.inc
rem
ent
=.1
3546
7E-0
1-.
51
67
87
E-0
20
+.6
93
54
7E
-03
02
-.1
38
21
8E
-Q4
03
Tre
atm
ent
3·
Hea
vyth
inni
ng,
nofe
rtil
izer
(T2F
01
R2
=0.
782
SEE
=0.
250
cm
R2
=0.
928
SEE
=4.
571
cm2
'" 0-R
2=
0.63
8SE
E=
0.22
5m
R2
=0.
962
SEE
=0.
0035
2m
3
dbh
incr
emen
t=
.660
648
+.3
6288
1E
-01
0+
.94
63
52
E-0
20
2-.
26
11
8E
-03
03
bain
crem
ent
=6.
7874
7-
1.46
103
0+
.421
625
02
-.5
11
77
0E
-02
03
htin
crem
ent
=-1
.99
30
5-.
99
39
87
E-Q
10
+1
.24
96
31
0
g.vo
l.in
crem
ent
=.2
41
98
6E
-04
-.8
34
81
3E
-03
0+
.26
25
10
E-0
30
2+
.19
83
66
E-0
50
3
Wh
ere
0=
init
ial
db
h
11F
or
hea
lth
yD
ou
gla
s-fi
rtr
ees
on
ly,
du
rin
gth
efir
st3
year
sfo
llow
ing
trea
tmen
t.
R2
=0.
735
R2
=0.
910
R2
=0.
704
R2
:0.
937
SEE
=0.
298
cm
SEE
=6.
374
cm2
SEE
=0.
196
m
SEE
=0.
0052
0m
3
Ap
pe
nd
ixV
.-
(Con
tinue
d)
Tre
atm
en
t4
-No
thin
nin
g,
224
kgN
lha
(UR
EA
)IT
OF
1)
dbh
incr
emen
t=
-.5
40
65
7+
.171
747
0+
.59
02
09
E-0
20
2-.
32
65
19
E-Q
30
3
bain
crem
ent
=.2
1195
5-
1.78
341
0+
.535
733
02
-.1
13
17
7E
-01
03
ht
incr
emen
t=
-3.6
11
50
-.3
26
04
00
+2
.78
18
5/0
g.vo
l.in
crem
ent
=-.
20
47
21
E-0
2-.
74
64
80
E-0
30
+.3
27
69
3E
-03
02
-.5
43
60
8E
-06
03
Tre
atm
ent
5-
Inte
rmed
iate
thin
nin
g,
224
kgN
lha
(UR
EA
)T
1F1)
R2
=0.
902
R2
=0.
956
R2
=0.
904
R2
=0.
970
SE
E=
0.2
84
em
SE
E=
5.19
6cm
2
SE
E=
0.24
1m
SE
E=
0.0
04
78
m3
db
hin
crem
ent
=-1
.68
01
9+
.694
618
0-.
43
66
68
E-Q
l0
2+
.112
432E
-02
03
bain
crem
ent
=-1
3.5
42
5+
3.54
797
0+
.120
953
02
+.8
50
34
4E
-03
03
hti
ncr
em
en
t=
-3.4
13
47
-.3
83
01
20
+2
.93
12
0/0
g.vo
l.in
crem
ent
=-.
80
65
77
E-0
2+
.12
35
82
E-0
20
+.2
18
78
4E
-03
02
+.3
002
E-0
50
3
Tre
atm
en
t6
-H
eavy
thin
nin
g,
224
kgN
lha
(UR
EA
)IT
2F
1)
R2
=0.
842
SEE
=8.
300
em
R2
=0.
948
SE
E=
5.52
6cm
2
R2
=0.
750
"S
EE
=0
.22
6m
.....
R2
=0
.97
0SE
E=
0.00
430
m3
db
hin
crem
ent
=-.
44
07
1O
E-0
1+
.37
52
56
0-.
80
59
25
E-Q
20
2-.
59
96
18
E-0
40
3
bain
crem
ent
=6.
4107
1-2
.04
27
50
+.9
0091
00
2-.
24
98
76
E-O
l0
3
ht
incr
emen
t=
-2.3
40
37
-.1
90
15
50
+1
.89
76
4/0
g.vo
l.in
crem
ent
=.8
43
27
3E
-Ol
-.2
78
38
9E
-Q1
0+
.32
35
14
E-Q
20
2-.
92
07
28
E-0
40
3
Whe
re0
=In
itia
ldb
h
R2
=0.
663
R2
=0.
882
R2
=0
.60
1
R2
=0
.92
8
SE
E=
0.42
0em
SE
E=
9.29
2cm
2
SE
E=
0.28
2m
SE
E=
0.00
731
m3
App
endi
xV..
(Con
tinue
d)
Tre
atm
ent
7-
No
thin
nin
g,
448
kgN
lha
(UR
EA
)IT
OF
2)
db
hin
crem
ent
=-.
68
97
23
+.2
8893
0+
.18
83
79
E-0
20
2-.
35
25
6E
-03
03
bain
crem
ent
=.3
05
58
5-
1.85
377
0-
.699
177
02
-.1
64
24
7E
-01
03
ht
incr
emen
t=
-2.9
56
91
-.2
83
62
00
+2.
5470
9vD
g.vo
l.in
crem
ent
=-.
30
91
93
E-0
2+
.16
69
63
E-0
30
+.2
09
03
6E
-03
02
+.1
02
81
9E
-04
03
Tre
atm
ent8
·In
term
edia
teth
inn
ing
,44
8kg
Nlh
a(U
RE
A)
1T2F
2)
R2
=0
.87
6
R2
=0.
948
R2
=0.
806
R2
=0.
969
SE
E=
0.3
54
cm
SE
E=
5.67
9cm
2
SE
E=
0.3
50
m
SE
E=
0.0
04
48
m3
db
hin
crem
ent
=-1
.37
51
6+
.64
13
72
0-.
30
75
90
E-Q
l0
2+
.55
07
62
E-0
30
3
bain
crem
ent
=-1
4.6
54
5+
3.46
806
0+
.324
712
02
-.8
00
92
2E
-02
03
ht
incr
emen
t=
-2.7
73
89
-.3
54
94
80
+2
.68
46
91
0
g.vo
l.in
crem
ent
=-.
11
26
84
E-Q
l+
.18
60
60
E-Q
20
+.2
82
22
7E
-Q3
02
_.3
70
68
5E
-07
03
Tre
atm
ent
9·
Hea
vyth
inn
ing
,44
8kg
Nlh
a(U
RE
A)
(T2
F2
)
R2
=0.
758
SEE
=0
.45
6cm
R2
=0
.91
2S
EE
=8
.51
8cm
2IV ex
>
R2
=0
.69
4S
EE
=0.
240
m
R2
=0.
952
SE
E=
0.0
06
26
m3
db
hin
crem
ent
=-1
.76
03
0+
1.08
279
0-.
74
80
73
E-Q
10
2+
.18
87
95
E-0
20
3
bain
crem
ent
=-5
2.0
51
2+
16.9
697
0-.
76
72
95
02
+.2
32
24
3E
-01
03
ht
incr
emen
t=
.917
45-.
95
81
32
E-Q
l0
+.7
29
25
21
5
g.vo
l.in
crem
ent
=-.
20
30
59
E-0
2-.
56
71
97
E-0
30
+.7
07
37
4E
-03
02
-.1
52
30
8E
-04
03
Whe
re0
=In
itia
ld
bh
R2
=0.
564
R2
=0.
874
R2
=0.
043
R2
=0
.91
1
SE
E=
0.49
4cm
SE
E=
11.4
60cm
2
SE
E=
0.3
83
m
SE
E=
0.00
989
m3
29
Appendix VI. Dbh frequency distributions by treatments showing initial condition and number oftrees lost through thinning and mortality (cross hatched).
TREATMENTS
Fa
---TO---
Fa
---T,---
Fa
---T2---
FI
CONDITION
24624624635 35 35
24624624635 35 35
THINNING ANa {D}MORTALITY 0 INITIAL
24624624635 35 35
200
1200
1400
w 1000
'"..>-"WI'"W0- 800u>ww'">-~
0
'" 600w<D:>=>z
400
DBH CLASSES
Ap
pen
dix
VII
I.PA
lfo
'ba
by
db
hcl
asse
san
dt'
eatm
ents
Init
ial
db
hT
reat
men
ts
Cla
ssM
idpo
int
lem
}TO
FOTO
F1T
OF2
T1F
OT1
Fl
T1F
2T
2F
OT
2F
lT
2F
2
Co
ntr
ol
a)T
otal
bain
crem
ent/
tree
*(c
m2 )
26.
251.
662.
414.
012.
814.
525.
924.
297.
589.
90
38.
753.
966.
018.
875.
489.
1111
.73
7.62
13.5
917
.75
411
.25
7.19
10.6
114
.85
8.93
14.3
018
.02
12.1
420
.62
24.9
4
513
.75
11.2
315
.85
21.4
312
.93
20.1
124
.53
17.7
027
.90
32.2
0
b)B
ain
crem
ent
gain
abov
eco
ntr
ol
(cm
2)
~2
6.25
0.00
0.75
2.35
1.15
2.86
4.26
2.63
5.92
8.24
38.
750.
002.
054.
911.
525.
157.
773.
669.
6313
.79
411
.25
0.00
3.43
7.66
1.74
7.11
10.8
34.
9513
.44
17.7
5
513
.75
0.00
4.62
10.2
01.
708.
8813
.30
6.47
16.6
720
.97
·Oe
riv
ed
fro
mre
gres
sion
equ
atio
ns
Ap
pen
dix
V.
Ap
pen
dix
IX.
PAl
for
heig
htby
dbh
clas
ses
and
trea
tmen
ts
Init
ial
dbh
Tre
atm
ents
Cla
ssM
idpo
int
lem
}TO
FO
TO
F1
TO
F2
T,F
OT
1F1
T1F
2T
2F
OT
2F1
T2
F2
Con
trol a}
Tot
alhe
ight
iner
emen
t!tr
ee(m
)'
26.
250.
360.
440.
550.
320.
510.
570.
170.
410.
71
38.
750.
460.
590.
700.
380.
640.
690.
280.
540.
75
411
.25
0.52
0.68
0.80
0.44
0.70
0.74
0.36
0.63
0.76
513
.75
0.55
0.74
0.86
0.49
0.73
0.77
0.42
0.69
0.77
b)H
eigh
tin
crem
ent
gain
abov
eco
ntro
l1m
)w '"
26.
250.
000.
080.
19-0
.04
0.15
0.21
-0.1
90.
050.
36
38.
750.
000.
130.
24-0
.07
0.18
0.23
-0.1
8-.
08
0.29
411
.25
0.00
0.17
0.28
-0.0
80.
190.
23-0
.16
0.11
0.25
513
.75
0.00
0.19
0.31
-0.0
60.
180.
22-0
.12
0.14
0.22
*D
eriv
edfr
om
regr
essi
oneq
uat
ion
sA
pp
en
dix
V.
Ap
pen
dix
X.
PAl
for
gros
svo
lum
eb
ydb
hcl
asse
san
dtr
eatm
ents
.
Init
iald
bh
Tre
atm
ents
Cla
ssM
idp
oin
t(e
ml
TOFO
TOF
1T
OF2
T1
FO
T1F
1T
1F
2T
2F
OT
2F
lT
2F2
Co
ntr
ol a)
To
tal
gros
svo
lum
ein
crem
ent/
tree
(m3
)*
26.
250.
0014
0.00
200.
0029
0.00
170.
0030
0.00
380.
0018
0.00
470.
0061
38.
750.
0036
0.00
540.
0071
0.00
410.
0072
0.00
890.
0047
0.00
890
.01
23
411
.25
0.00
710.
0101
0.01
330.
0078
0.01
260.
0151
0.00
890.
0165
0.0
19
8
513
.75
0.01
170.
0161
0.02
180.
0126
0.01
940.
0225
0.01
440.
0261
0.02
81
bl
Gro
ssvo
lum
ein
crem
ent
gain
abov
eco
ntr
ol
(m3
)w w
26.
260.
0000
0.00
060.
0015
0.00
030.
0016
0.00
240.
0005
0.00
340.
0048
38.
750.
0000
0.00
170.
0034
0.00
040.
0035
0.00
520.
0011
0.00
530.
0087
411
.25
0.00
000.
0030
0.00
620.
0007
0.00
550.
0080
0.00
180.
0094
0.01
27
513
.75
0.00
000.
0044
0.01
010.
0009
0.00
770,
0108
0.00
270.
0129
0.01
64
...D
eriv
edfr
om
regr
essi
oneq
uat
ion
sA
pp
end
ixV
.
Ap
pen
dix
XI.
Tre
efr
eque
ncy
dist
ribu
tion
sby
dbh
clas
san
dtr
eatm
ent
used
inst
and
stru
ctur
ean
alys
is.
(a)
Act
ualt
ree
freq
uenc
ydi
stri
buti
ons
bytr
eatm
ents
asth
eyoc
cur.
Init
iald
bh
Num
ber
oftr
ees
bytr
eatm
ent
Cla
ssM
idp
oin
tle
m)
TOFO
TO
Fl
TO
F2
T1F
OT1
F1
T1F
2T
2F
OT
2F
lT
2F
2
3.75
3620
242
23
00
0
26.
2558
3540
1414
151
23
38
.75
5644
4727
2432
16
1112
411
.25
3430
2726
2424
1317
15
51
3.7
59
105
89
75
55
616
.25
12
22
22
11
2
w7
18.7
51
20
00
00
00
l>-
(b)
Mea
ntr
eefr
eque
ncy
dist
ribu
tion
sfo
rea
chth
inni
ngle
vel.
Init
iald
bh
Num
ber
oftr
ees
bytr
eatm
ent
Cla
ssM
idp
oin
tle
m)
TOF
OT
OF
1T
OF
2T
1FO
T1F
1T
1F2
T2
FO
T2
F1
T2
F2
3.75
2626
262
22
00
0
26.
254
44
444
1414
142
22
38
.75
49
49
4928
2828
131
313
411
.25
3030
3024
2424
1515
15
513
.75
88
88
88
55
5
616
.25
22
22
22
718
.75
11
10
00
00
0
Ap
pe
nd
ixX
I(C
ontin
ued)
(c)
Hyp
oth
etic
altr
eefr
equ
ency
dis
trib
uti
on
.
Init
iald
bh
Num
ber
of
tree
sb
ytr
eatm
ent
Cla
ssM
idp
oin
t(e
m)
TOF
OTO
F1T
OF
2T
1FO
T1F
1T
1F
2T
2F
OT
2F
1T
2F
2
3.75
00
00
00
00
0
26.
253
33
33
33
33
w '"3
8.75
1010
1010
1010
1010
10
411
.25
1414
1414
1414
1414
14
513
.75
55
55
55
55
5
616
.25
22
22
22
22
2
718
.75
00
00
00
00
0
App
endi
xX
II.
Act
ual
and
adju
sted
PA
lfo
rgr
oss
volu
me
by
cova
rian
cean
alys
isus
ing
the
39
5an
d6
18
larg
est
tree
sp
erh
ecta
re(m
3)
Tre
atm
ent
Act
ual
Gai
no
ver
%G
ain
abov
eA
dju
sted
Gai
no
ver
%G
ain
abov
eA
ctua
lA
ctua
lA
djus
ted
Adj
uste
dC
on
tro
lC
on
tro
lC
ontr
olC
on
tro
l
a)39
5la
rges
ttr
ees/
ha
TO
FO
(con
trol
)4.
525
00
4.04
00
0
TO
F1
7.69
13.
165
70.0
5.48
31.
443
35.7
TO
F26.
958
2.43
353
.87.
875
3.83
594
.9
T1
FO4.
817
0.29
26.
54.
270
0.23
05.
7
T1F
17.
724
3.19
970
.77.
286
3.24
680
.3
T1F
28.
291
3.76
683
.28.
309
4.26
910
5.7
T2
F O4.
627
0.10
22.
25.
598
1.55
838
.6
T2
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