May 4, 2009 8:00 pm US/Eastern
Scientist Tracks Trees Coming Back To Life
BOSTON (WBZ) ―
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Scientists call this annual spring ritual "leaf out" or "bud burst," but it doesn't happen at the same time every year.
WBZ
Everywhere you look, buds are bursting and leaves are unfolding as trees come back to life.
Scientists call this annual spring ritual "leaf out" or "bud burst," but it doesn't happen at the same time every year. "The most important factor affecting whether it's an early spring with early green up or a later spring is air temperature," said University of New Hampshire ecologist Andrew Richardson. "In a warmer spring, buds develop more quickly and the leaves expand more rapidly."
Richardson would know. He has been studying thousands of "leaf out" images captured by a scattering of Web cameras perched high above tree canopies in 80 locations across the country.
The network is called
"PhenoCam," because the project is focused on "phenology"-- how the timing of the seasons affects plants and animals. "Images are sent out automatically to our image archive every half hour," said Richardson, "We have literally hundreds of thousands of archive images from the past several years."
Since trees are so temperature sensitive, they are a good indicator of the arrival of spring and that timing can have implications for climate science.
"From our analysis of these tree canopy images we can get a seasonal trend in the greeness of trees," said Richardson.
Based on that data, in the Boston area the leaves usually emerge around day 120 in the year, or early May.
According to Richardson, this timing can vary by three to four weeks year-to-year, depending on spring weather patterns. "The greeness of the canopy tapers somewhat over the summer as the leaves age," he added.
But it's when the leaves first appear in spring that could have implications on global climate. "Basically, the earlier that the leaves come out, the longer the trees have to grow. The more they can grow, the more CO2 they can take up," concluded Richardson.
This research is part of a larger national effort to study the timing of the seasons and the impact on plants and animals. Scientists across the country are looking for
citizen volunteers to help. So you may want to take a closer look at those leaves. They have a climate story to tell.
Calculate the amount of carbon a tree in your yard can take up.
Request to have a tree planted at your home in Boston.
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