Year 11 | 10 December 2019 | TO ENTER | TO REGISTER

Trees store more carbon with global warming

A study of the Marine Biological Laboratory shows that warmer temperatures stimulate the gain of carbon stored in trees

A study led by Jerry Melillo was done in Harvard Forest in central Massachusetts, in which a section of the forest (about one-quarter of an acre) was artificially warmed about 9 degrees above ambient, to simulate the amount of climate warming that might be observed by the end of the century without aggressive actions to control greenhouse gas emissions from fossil-fuel burning and deforestation.

The study confirmed, as others have, that a warmer climate causes more rapid decomposition of the organic matter in soil, leading to an increase in carbon dioxide being released to the atmosphere.

But the study also showed, for the first time in a field experiment, that warmer temperatures stimulate the gain of carbon stored in trees as woody tissue, partially offsetting the soil carbon loss to the atmosphere. The carbon gains in trees, the scientists found, is due to more nitrogen being made available to the trees with warmer soil.

Researchers think that the biological processes that link soil warming, increased soil organic matter decay, increased nitrogen availability to trees, and increased tree growth will likely operate together in many temperate and boreal forests -- forests found in North America, Europe, Eurasia and much of the developed world. Tree growth in tropical forests is often limited by factors other than nitrogen, so lessons from this new study are not widely relevant in the tropics.

by Ernesto Vania
06 june 2011, Food & Fun > Nature