logging in the brazilian amazon michael keller usda forest service int’l institute of tropical...
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Logging in the Brazilian Amazon
Michael Keller
USDA Forest Service
Int’l Institute of Tropical Forestry
Logging in the Brazilian Amazon
• Extent of Logging
• Logging Techniques
• Logging Effects – Carbon
• Long Term Sustainability?
Selective Logging
Nepstad et al, 1999
Logging Centers in the Brazilian Amazon Region
1999 2000
AutoMCU Results
Asner et al., in press
Logging Approaches
• Conventional Logging
• Reduced Impact Logging
• Sustained Yield Management
• Sustainable Forest Management
Pereira et al. (2002) Forest Ecology and Management)
0%
10%
20%
30%
40%
50%
60%
70%
0 10 20 30 40 50 60 70 80
Volume Harvested (m^3)
Can
op
y L
ost
(%)
CL
RIL
CL Best Fit
RIL Best Fit
Pereira et al. (2002) Forest Ecology and Management
Logging and Carbon
• Carbon losses and recovery following logging
• Comparison of logging practices
Carbon Loss (Tg C) from Logging30 Year Integration, 15000 km2 y-1
Slow decay Fast decay
Conventional
Logging28.7 29.1
Reduced
Impact18.5 18.3
(Keller et al. in press)
Logging and Sustainability
• Biological– Water and Energy Exchange– Carbon Storage– Nutrient Cycling– Habitat and Diversity
• Production system
• Economic and social
Potential Nutrient Limitation: Selective Logging (30 m3 removed each 30 y)
[Nutrients in kg ha-1 y-1]
ElementNutrient in Soil (1 m)
Nutrient in Harvest
Stock/Removal (Years)
N 9010 56 4805P 1676 1 44701K 111 14 246Mg (*) 43 9 143Ca 63 18 105
(*) Estimated maximum Mg owing to detection limit
Data from Silver et al. 2000 and Fernandes et al. 1997
Logging and Sustainability
• Production Systems– Given realistic inputs, costs, and
benefits, at what rate can logs be selectively removed from the forest over a long period of harvest cycles?
– A critical factor in determining production system sustainability is the range of species acceptable to the market.
Keller et al. in press
CAFOGROM Model (Alder & Silva)
Logging and Sustainability
• Long term sustainability of logging depends upon protection of the forest against risks such as fire.
Susceptibility
Forest Fire
Logging
Forest Fire
Risk: Positive Flammability Feedback
Source: Nepstad et al. 2001
Conclusions
• Selective logging may release substantial carbon to the atmosphere but this is highly dependent upon area logged and the logging techniques.
• Nutrients, with the possible exception of K, Mg, and Ca, are unlikely to severely limit productivity on most soils
• With good management, current models suggest that log production may be maintained at presently profitable levels if the number of merchantable species increases in the future
Acknowledgements
• Natalino Silva, Greg Asner,
• MCT and the LBA Central Office at CPTEC
• LBA-ECO Project
• Johan Zweede and FFT
• NASA, US Forest Service, USAID, DFID, EMBRAPA
Estimation of Potential Nutrient Limitation: Selective Logging (30 m3
removed each 30 y) [Nutrients in kg ha-
1 y-1]
(*) Estimated maximum Mg owing to detection limit
Data from Silver et al. 2000, Fernandes et al. 1997, & Williams et al. 1997
ElementNutrient in Soil (1 m)
Removed per year
Rainfall Input per year
N 9010 1.88 4.16P 1676 0.04 0.34K 111 0.45 0.90Mg (*) 43 0.30 0.30Ca 63 0.60 1.32