There may be less reason for gloom and doom at the sight of a patch of logged rain forest. Within a decade of selective logging, forests can recover levels of tree species diversity similar to those in unlogged areas, according to a study in this week's Science.
Until now, researchers thought that even selectively logged areas suffered from a decline in tree species diversity. The researchers hypothesized that young trees did not have much of a fighting chance against the erosion, soil compaction, and loss of tree canopy shelter caused by logging. However, for all the speculation, "there is amazingly little scientific information about the influence of selective logging," says John Battles, a forest community ecologist at the University of California, Berkeley.
Researchers led by botany doctoral student Charles Cannon at Duke University in Durham, North Carolina, set out to examine the issue. The researchers counted the number of species of trees on parcels of land in the Indonesian Borneo rain forest that had been selectively logged for tall trees, either 1 or 8 years ago. They then counted the number of species of trees in areas that were intermixed with these logged areas but were not harvested because they were inaccessible. The researchers found that areas that had been logged 1 year before had 43% fewer tree species than unlogged forests. To their surprise, however, they found that forests logged 8 years ago had diversity similar to forests that were not logged.
The good news should be a call to action, says Robin Chazdon, an ecologist and evolutionary biologist at the University of Connecticut in Storrs. "There has not been enough emphasis on the value of a logged or otherwise degraded area," she says. "We view these [logged forests] as our table scraps, but they are going to be our main course in the future." She says greater measures must be taken to conserve the toppled timber forests so they are not converted to agricultural land, and to preserve enough of the original forests to provide seeds to repopulate the logged areas.