Trees Grow Faster Because of Global Warming

Forests could be growing faster now than they were 225 years ago as a result of global warming, a study has revealed.

The study, published on Monday in the Proceedings of the National Academy of Sciences, found evidence that trees in the eastern United States were growing at an accelerated rate due to the rising levels of atmospheric CO2, higher temperatures and longer growing seasons.

Scientists in Maryland, VA documented changes to the growth of 55 plots of mixed hardwood forest over 22 years, and concluded the younger trees were growing much quicker than the eldest trees in the study, which were 225-years-old, a Smithsonian Environmental Research Center (SERC) blog reported Monday.

Forest ecologist Geoffrey Parker of the SERC and Sean McMahon of the Smithsonian Tropical Research Institute discovered that, on average, the forest was growing an additional two tons per acre annually, the equivalent of a tree with a diameter of two feet sprouting up over a year.

The scientists agreed that if the older trees had grown at the same rate throughout their lives as the younger trees were now, they would be much larger.

Parker began his tree census work Sept. 8, 1987, and measured all trees that were 0.8 inches or more in diameter, and then identified their species. By knowing the species and diameter, he was able to calculate the trees biomass.

During the past 22 years CO2 levels at SERC rose 12 percent, the temperature increased by nearly three-tenths of a degree Celsius and the growing season lengthened by 7.8 days. Parker and McMahon suggested that a combination of these factors caused the forest’s accelerated biomass gain.