Reforestation outpacing deforestation?

While most people associate cities with pollution and the material and ecological excess of late capitalism, I've long believed that urbanization has the potential to be a great environmental savior. The NYT has a fascinating article that confirms what I said about cities attracting people who would otherwise live more environmentally profligate lives: the amount of total rain forest is likely growing, due to the reforestation of towns and villages abandoned by people in Latin America and Asia who are moving to cities. Elisabeth Rosenthal, the article's author, explains the reasons that people are abandoning land at a growing pace:

In Latin America and Asia, birthrates have dropped drastically; most people have two or three children. New jobs tied to global industry, as well as improved transportation, are luring a rural population to fast-growing cities. Better farming techniques and access to seed and fertilizer mean that marginal lands are no longer farmed because it takes fewer farmers to feed a growing population.

By some estimates, these demographic and technological shifts mean that forests are growing back far faster than they're being cut down:

These new “secondary” forests are emerging in Latin America, Asia and other tropical regions at such a fast pace that the trend has set off a serious debate about whether saving primeval rain forest – an iconic environmental cause – may be less urgent than once thought. By one estimate, for every acre of rain forest cut down each year, more than 50 acres of new forest are growing in the tropics on land that was once farmed, logged or ravaged by natural disaster.

There are two problems, though, with the new forests: they aren't "old growth" forests, and they aren't necessarily able to support many endangered species. The first part – the fact that they are "secondary" forests and not primeval – might be important in that it means the ecosystem is not as dense and complex as it would be in, say, a rain forest that hasn't been touched since pre-Colombian times. Scientists haven't reached a consensus on how significant this is, though it's comforting to note that as time passes, the now-secondary forests will become denser and older. As for the endangered species, it's a combination of the first point (new growth) and the fact that these new jungles are growing in different places than the forests which are being cut down, and are not reachable by the animals that are endangered within the old growth.

Reading this makes me think of a Wired article from a few years back about the Mayans and the rain forest, and how much of the Yucatán jungles are likely to be feral gardens of the ancient Mayans.