Global warming good for trees

GLOBAL warming is good news for trees, which are thriving in higher temperatures and longer growing seasons, but bad news for ducks and other waterfowl, whose wetland habitat may dry up and disappear, two studies show.

A study by researchers at the Smithsonian Environmental Research Center (SERC) in Maryland indicates that higher temperatures, longer growing seasons and increased levels of carbon dioxide brought by climate change are helping trees in temperate climates to grow faster.

The researchers studied data on how many trees there were in 55 forests in the eastern United States during a 22-year period, as well as 100 years of local weather measurements and 17 years of carbon dioxide measurements. Their findings, which were published this week in the Proceedings of the National Academy of Science (PNAS) show that recent tree growth 'greatly exceeded the expected growth,' and they hypothesized that the spurt was due to climate change.

'Increases in temperature, growing season and atmospheric CO2 have documented influences on tree physiology, metabolism and growth and likely they are critical to changing the rate of ... growth observed,' says the study.

Rising temperatures have increased the metabolic processes of trees and extended their growing season, while higher levels of carbon dioxide in the atmosphere could be spurring tree growth through carbon fertilisation, the study says.

But for ducks and other waterfowl, rising temperatures are bad news, according to a separate study conducted by researchers from the US Geological Survey and South Dakota State University and published this week in the journal BioScience.