Condition and fate of logged forests in the Brazilian Amazon

Abstract

The long-term viability of a forest industry in the Amazon region of Brazil depends on the maintenance of adequate timber volume and growth in healthy forests. Using extensive high-resolution satellite analyses, we studied the forest damage caused by recent logging operations and the likelihood that logged forests would be cleared within 4 years after timber harvest. Across 2,030,637 km2 of the Brazilian Amazon from 1999 to 2004, at least 76% of all harvest practices resulted in high levels of canopy damage sufficient to leave forests susceptible to drought and fire. We found that 16+/-1% of selectively logged areas were deforested within 1 year of logging, with a subsequent annual deforestation rate of 5.4% for 4 years after timber harvests. Nearly all logging occurred within 25 km of main roads, and within that area, the probability of deforestation for a logged forest was up to four times greater than for unlogged forests. In combination, our results show that logging in the Brazilian Amazon is dominated by highly damaging operations, often followed rapidly by deforestation decades before forests can recover sufficiently to produce timber for a second harvest. Under the management regimes in effect at the time of our study in the Brazilian Amazon, selective logging would not be sustained.

Fig. 1.

Annual logging intensity throughout a four-state region of the Brazilian Amazon. Logging intensity is expressed as AIGF at 1-km resolution. Gap classes range from 1 (0–10% AIGF) to 10 (>90% AIGF). Deforested areas (D; blue) are compiled from INPE (www.obt.inpe.br), with cumulative deforestation from 1997 to 2000 shown (Top) and annual increments for the subsequent years shown (Bottom). Gray areas show federal conservation lands and indigenous reserves.

Fig. 2.

Cumulative forest gap fraction (30-m scale) distributions for selectively logged areas before harvest in 1999, after initial harvest in 2000, and 1 and 2 years after logging in 2001 and 2002, respectively.

Fig. 3.

The proportion of year 2000 logging and intact forest subsequently deforested by 2004 across the Amazon study area at distance classes of 0–50 km from major roads. The Pearson significance of χ² comparisons between the deforestation of logged or intact points per distance class is shown as: ns, nonsignificant; ∗, P < 0.05; ∗∗, P < 0.01; and ∗∗∗, P < 0.001. (Inset) The cumulative distribution of logged forest (1999–2002) and intact forest as a function of distance from main roads.