news @ nature.com - Rising temperatures "will stunt rainforest growth" - Plants suffering in the heat could make global warming worse.

news @ nature.com - Rising temperatures "will stunt rainforest growth" - Plants suffering in the heat could make global warming worse.

A lot of people hope that reforestation or avoided deforestation will limit some of the increases in greenhouse gas levels in the atmosphere. Most people understand the simple story of how living plants absorb carbon dioxide, but this show how the system is more complex. Plant do increase in productivity up to a threshold and then they are not able to photosynthesise. Worst still, if trees die then they may rot, producing methane in large volumes, which is a very effective greenhouse gas. These problems apply both in northern and tropical forests. In northern forests, the other big issue is that there is actually more carbon in the soil than in the trees themselves. A study in the UK found net losses of carbon dioxide from soil reserves in recent years. So tree planting, while attractive in terms of the story, is much more complex than it seems.