Posted by: brian | February 21, 2009

Good environmental news

Tropical rainforests are recovering from clearcutting faster than anticipated.

In many places, trees are growing back, according to new research, and some of the new forests are nearly as diverse as the old ones were.

This is wonderful to hear. It’s awesome to see how resilient nature can be, and while it doesn’t mean that human impact on the environment is negligible, it does mean that when we make efforts to mitigate the damage we’ve done, nature is ready to bounce back.

“When I started out, if you picked up an ecology textbook, it would say that once a tropical forest was cleared, it would never grow back,” said ecologist Robin Chazdon, of the University of Connecticut in Storrs. Her work is helping rewrite the books. “I view it as a hopeful message.”

Seriously? Ecologists claimed that forests would NEVER grow back? That was a short-sighted assertion. And a bit of a stupid one too.

For nearly 20 years, Chazdon has been working in Costa Rica to see how new forests compare to old ones. In her studies, she has attempted to identify all tree species in relatively large plots of forest. Her plots include both pristine, old-growth areas and newer, second-growth forests that have only recently overtaken abandoned pastures.

At a recent biodiversity symposium in Washington, D.C., Chazdon reported encouraging results. She has found that, after just 20 or 30 years, second-growth forests can have just as much biomass as old-growth forests do. Biomass is a measure of the total plant life in an area.

Yes, there are those who want to throw a wet blanket on this news,  cautioning that the rate of recovery is dependent on many factors, and that this doesn’t absolve us of all the mistakes we’ve made. And the fact that just because the plants are back doesn’t mean that recovery is complete. Duh. But I guess when you’re writing for a public that doesn’t understand science, and that considers the soundbite to be a legitimate form of information delivery, you need to include statements about what ought to be patently obvious to someone with a high school education.

Still, the work is not a sign that deforestation is OK, cautioned ecologist Karen Holl, of the University of California, Santa Cruz. How quickly an abandoned pasture can recover depends on many factors –from how intensively the land was used to how close it is to a mature forest. In many places, second-growth forests are not faring nearly as well as the forests Chazdon has studied.

And even where trees re-colonize and thrive, plenty of questions remain about whether the rest of the ecosystem will follow.

All of this should be obvious if you understand that Chazdon is not studying EVERY SINGLE DEFORESTED PLOT IN SPACE-TIME. The point is, conservation efforts can make as much of a difference as deforestation efforts did, albeit at a more gradual pace.

[Chazdon’s] findings suggest that conservation efforts should target the world’s increasing number of second-growth forests, as they continue to protect the decreasing number of old growth forests. The research also points out that “pristine” might not be the most realistic goal when it comes to conservation.

This is great news, because it illustrates a couple of things I’ve always believed:

  • We cannot destroy the world. We can make it a miserable place, and maybe even kill ourselves off, but life will always find new ways to thrive if we give it a chance.
  • Evolution is key. These rainforests may not be identical to what was there before, but they will regain biodiversity as animals and plants adapt to changing conditions.

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