effects of forest management practices on carbon storage
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Effects of Forest Management Practices on Carbon Storage. Coeli M. Hoover USDA Forest Service, Northern Research Station Forest PLUS, Washington DC December 6, 2013. Trail Map. Management effects on aboveground C stocks Long-term thinning studies - PowerPoint PPT PresentationTRANSCRIPT
Effects of Forest Management Practices on Carbon Storage
Coeli M. HooverUSDA Forest Service, Northern Research Station
Forest PLUS, Washington DCDecember 6, 2013
Trail Map
• Management effects on aboveground C stocks– Long-term thinning studies
• Management treatment effects on forest floor and soil C stocks– State of knowledge– Results from field study
• Questions
Management Effects on Aboveground Carbon Stocks
Long-term Thinning Studies
• Thinning studies with long measurement records can be used to investigate the carbon consequences of different management practices
• Studies are usually of similar design, and apply a variety of thinning levels
• Structure study at Kane EF was designed specifically to look at effect of method, using a single density
• Challenges – lack of documentation, control plots, irregular measurement intervals, etc.
Aboveground Live Tree Carbon
1975 1980 1985 1990 1995 2000 20050
20
40
60
80
100
120BelowAboveControl
Indicates when a thinning treatment occurred
Year
mtC
/ha
Structure Study - KEF
Structure Study - KEFAverage Annual Change - AGL Carbon
Below Above Control-2.5
-2.0
-1.5
-1.0
-0.5
0.0
0.5
1.01975-19891975-2005
Treatment
mtC
/ha/
yr
Crop Tree Thinning - BEFAboveground Live Tree Carbon
1958 1969 1975 19900
20
40
60
80
100
Heavy
ControlLight
Year
mtC
/ha
Crop Tree Thinning - BEF
Average Annual Change - AGL Carbon
Heavy Light Control0.0
0.5
1.0
1.5
2.0
2.5
3.01964-19751958-1990
Treatment
mtC
/ha/
yr
Mixed Oak Stocking- Vinton Furnace EF
1962 1976 1984 1996 20060
20
40
60
80
100
120
Aboveground Live Biomass Carbon
40%50%70%100%
tC/h
a
Mixed Oak Stocking
Average Annual Change - AGL Carbon
40% 50% 60% 70% Control0.0
0.5
1.0
1.5
2.01966-19841962-2006
Treatment
mtC
/ha/
yr
Summary• Over the long term, plots
will often end up with about the same amount of live biomass carbon across treatments
• However, the rate of accumulation may be quite different, especially in the period following treatment
Are your goals short- or long-term?
Management Impacts on Forest Floor and Soil C Stocks
Mini literature review – mineral soil
• Overall, significant effects of harvesting on soil C have not been detected– Some evidence that boreal soils may respond
• Some cases of short-term increases in C in surface soils
• A few cases of short-term decrease in C in either the surface or deeper soils
• Some evidence that changes may occur at depth over longer time frames, but few studies have addressed this topic
Mini literature review - forest floor
• Literature includes chronosequences and control/treatment studies
• Problem of mixing of forest floor and mineral soil often complicates interpretation of results
• Good evidence that forest floor carbon stocks often decline after harvest– Recovery may take several decades
Most recent meta-analysisNave et al. 2010 (Forest Ecology and Management)
• Analyzed C content (t/ha) and concentration (% C)
• 75 publications met criteria– Control and harvest– Temperate forest
• Analyzed 432 response ratios from papers published between 1979-2008
• Largest analysis to date
Overall results from Nave et al. 2010
• Forest floor– C storage declined by 30±6% after harvest– Significantly different between hardwoods and
softwoods• Conifer/mixed stand: -20%• Hardwood stand: -36%
• Mineral soil– No significant overall effect– Variation best explained by soil taxonomy
Overall results…
Nave et al. 2010
Digging deeper…
Nave et al. 2010
Results from regional work
• Investigated surface soil and forest floor C stocks in long-term thinning studies
• Variety of treatments: clearcutting, thinning to different densities– e.g., 90 ft2, 60 ft2, 30 ft2, 70% RD, 40% RD
• All sites northern hardwood• States included WV, NY, PA, WI, NH• Some sites treated once, others twice• Results in Carbon Balance and Management
2011(C. M. Hoover)
Forest Management Effects Study Sites
Argonne
Bartlett
SUNY Heiberg
Kane
Fernow
Middle Mountain
Results Summary• Forest floor stocks were variable, ranging from
2.4-18 mtC/ha– General trend of increasing S to N– No significant effects related to treatment
• Surface (0-20 cm) soil stocks range from a low of 32 to a high of 78 mtC/ha– Most sites fall between 55-65 mtC/ha– Overall, no treatment effects on C stocks or C
concentrations – Similar patterns for 0-5 cm depth as 0-20 cm
Kane Experimental Forest (PA)
0 2 4 6 8 10 12 14 16 18 2002468
101214161820
Light thinHeavy thin
tC/ha control
tC/h
a tr
eate
d
Forest Floor C Stocks –Thinned and Control
0 2 4 6 8 10 12 14 16 18 2002468
101214161820
1970
1952
1981
1996
tC/ha control
tC/h
a cl
earc
ut
Forest Floor C Stocks – Clearcut and Control
Fernow Experimental Forest (WV) Whole tree harvest
0 20 40 60 80 1000
20
40
60
80
100
Lightthin
Heavythin
tC/ha control
tC/h
a tr
eate
d
Soil C Stocks (0-20 cm)-Thinned and Control
0 20 40 60 80 1000
20
40
60
80
100
1981
1952
1970
1996
tC/ha control
tC/h
a cl
earc
ut
Soil C Stocks (0-20 cm)-Clearcut and Control
In summary...
• Thinning treatments may not change the standing C stock over time, but can strongly affect the rate of C accumulation– Thinning method matters!
• Common management treatments may cause a reduction in forest floor C stocks
• Strong evidence that common management treatments do not result in meaningful reductions in SOC stocks or concentrations
Points to ponder• Short-and long-term responses often differ
– This is true both above and below ground• Surface and deep soil layers may respond
differently• Site specific factors may come into play
– Hardwood/softwood types– Soil order
• Existing studies covered “standard” rotation lengths – not biomass harvests or industrial plantations
• Your mileage may vary!
Questions?