Tropical Forests Recover From Clear-Cutting

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Tropical Forests Recover From Clear-Cutting

Emily Sohn, Discovery News

Deforestation is generally considered to be bad news, especially in the tropics.

But there may be some hope: 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.

The work adds to a growing sense that tropical forests are more resilient than scientists previously thought and that second-growth forests are far from worthless.

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“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.”

As much as 60 percent of the world’s tropical forests have been cut or burned, primarily to make way for pastures. But now, even as deforestation continues at an alarming pace, an increasing number of pastures are being abandoned as a result of conservation efforts, changes in crop prices, even war.

In temperate regions such as New England, studies show that mature forests have successfully reclaimed many abandoned fields over the last 100 years. But much less is known about re-growth in tropical places, partly because hundreds of tree species can live in one small area of the tropics (compared to a dozen or so in New England), making research challenging.

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.

What’s more, about 90 percent of tree species from her old-growth plots are now growing in her younger plots, too. Many of those species appear as young saplings and seedlings, categories that previous studies had failed to look at. Bats, toucans, and other birds seem to be delivering seeds to the new forests, Chazdon said.

Her 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.

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.

“Yes, this is good news…but secondary forests are not a substitute for the original,” Holl said. “You can copy a Rembrandt and it may look the same, but that doesn’t necessarily mean it is exactly the same.”

<<Editors notE>>
As stated… try to preserve the rest of the woods until we know how the hell we can “control” nature without screwing it up for most lifeforms on it…
Remember we are not killing the planet… we’re killing everything ON it.

… Now grow my children, grow my seedlings, grow grow grow… into nice green… healthy stuff…

source:: discovery.com
© copyright:: discovery.com


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