The Future of Amazonia

The current New York Review of Books has an excellent piece by John Terborgh looking at the history of development in the Brazilian Amazon, and the forest's future prospects.

Terborgh's story and his arguments are too detailed to do justice here, but this, roughly, is his conclusion:

Brazil will continue to pursue its long-cherished goal of integrating the Amazon into the national economy. Much of the forest will go. But I would be surprised to see it vanish entirely because an increasing portion of the Amazon in Brazil, and in neighboring countries, is under formal, legal protection...Short of a complete breakdown of civil authority, the Amazon won't be entirely "lost".

He then sounds a note of caution: "Unforeseen developments are likely to determine the future of th Amazon... One such unforeseen development is fire, which holds the potential to be the undoing of the Amazon." Pristine tropical forest, he say, doesn't burn. Logging changes that:

Logging synergizes fire in two ways. First, cutting down trees opens the forest canopy, admitting sunlight and drying out the leaf litter on the forest floor. Second, the debris of branches, chips, and stumps left behind by logging operations serves as fuel for any subsequent fire.

The first time a tropical forest burns, the damage can hardly be detected from above because the destruction is largely confined to saplings and small trees whose crowns lie below the canopy. But the subsequent presence of large numbers of dead trees greatly increases the fuel available to stoke the next fire. Consequently, second fires burn hotter and more destructively, killing large trees as well as practically all smaller ones. And, of course, second fires generate even more fuel for the third fire. Colleagues of mine who study this subject, notably, Carlos Peres and Jos Barlow of the University of East Anglia (UK) and William Laurance of the Smithsonian Tropical Research Institute in Panama, assert that the third fire spells doom for the forest, since it kills all remaining trees.

Then, he adds, there's climate change, which will reduce rainfall, and dry the Amazon out from west to east (becasue the rain comes off the Atlantic) and threatens the 'savannaization' of the forest. In total, Terborgh's essay is all the more sobering for being balanced and unalarmist.