Logging in the Brazilian Amazon Michael Keller USDA Forest Service Int’l Institute of Tropical...

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