220 likes | 406 Vues
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.
E N D
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?
Logging Centers in the Brazilian Amazon Region Nepstad et al, 1999
AutoMCU Results 1999 2000 Asner et al., in press
Logging Approaches • Conventional Logging • Reduced Impact Logging • Sustained Yield Management • Sustainable Forest 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 (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] (*) 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.
CAFOGROM Model (Alder & Silva) Keller et al. in press
Logging and Sustainability • Long term sustainability of logging depends upon protection of the forest against risks such as fire.
Risk: Positive Flammability Feedback Susceptibility Forest Fire Logging Source: Nepstad et al. 2001 Forest Fire
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