Old-Growth Forests Help Combat Climate Change

Rare is the forest untouched by man. Whether logging or clearing land for agriculture, the bulk of the world's forests have fallen to crops, cattle or younger trees. According to some estimates, less than 10 percent of forests worldwide can be considered old growth, or undisturbed for more than a century. And that is not just a tragedy for the plants and animals that require mature forests—it is also a tragedy for the world's climate, according to a study published today in Nature.

Laborious research in the 1960s by the late pioneering U.S. ecologist Eugene Odum seemed to indicate that forests achieve a balance between the amount of carbon dioxide (CO2) absorbed by growing trees and plants and the amount of CO2 released back into the atmosphere by the decomposition of dead plant matter.

But it seems that old forests may be more efficient than previously believed. Biologist Sebastiaan Luyssaert of the University of Antwerp in Belgium and his colleagues surveyed all the existing measurements of how much carbon is absorbed and released from old-growth forests (exclusively in temperate and boreal forests due to a lack of extensive data on tropical forests). Their findings, Luyssaert says: "old-growth forests continued to accumulate carbon."

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See our earlier posting about the same matter.
The painting is by Laura Tasheiko