Report: Global Warming Threatens Rich Fall Colors
by: Stan Freeman 12 October 2006
New England's iconic autumn foliage, spectacular in its color, may one day fade permanently rather than just annually.
Some climate scientists say that even if steps are taken now to limit global warming, temperatures in New England will rise enough over the next half-century that the source of much of that rich fall color, the sugar maples, will disappear from most of the region. Healthy stands of sugar maples may be found eventually no farther south than Canada and northern Maine.
"It's inevitable. It was thought that it would happen in 100 or 200 years. Now we're really looking at those kinds of changes happening much more quickly, maybe by midcentury," said Barrett N. Rock, a professor of natural resources at the Institute for the Study of Earth, Oceans and Space at University of New Hampshire.
A report from the Union of Concerned Scientists last week, "Climate Change in the U.S. Northeast," said that if nothing is done to reduce the emissions of greenhouse gases into the atmosphere, the climate of Massachusetts will resemble that of South Carolina by the end of the century, with nearly 65 days a year when temperatures in Boston exceed 90 degrees, as compared with about 10 now.
However, even if steps are taken globally to reduce emissions, the Massachusetts climate will still resemble that of Maryland by the end of the century and Boston will still experience nearly 30 days a year of 90-plus temperatures, the report said.
That unavoidable rise in temperatures will mean the decline of sugar maples, as well as other cool-weather-loving tree species, such as beeches and birches, in New England, as younger trees will not generate to replace older trees that die. Historically, the southern limit of the range of sugar maples has been northern Virginia; however they are most common in New England, New York and southern Canada.
David B. Kittredge, a professor of natural resources at University of Massachusetts in Amherst, said that while a warming climate will lead to the loss of some species of trees in New England, other species, tolerant of warmer temperatures, will migrate into the region from the south.
"There are plenty of hardwoods down south, but they don't turn the kind of colors that sugar maples do. You have oaks and hickories in southern forests, but they are kind of boring by contrast," he said.
The loss of sugar maples and its effect on the autumn foliage will likely mean the loss of tourist dollars.
However, the warming climate may have already meant a decline in the maple sugaring industry in New England. The flow of sap from sugar maples is sensitive to temperature. And the Union of Concerned Scientists' report estimated that the average yearly temperature in the Northeast has warmed about 2 degrees since 1970.
"With sugar maples, you need to have those cold nights and warm days to get the right kind of sap flow. If the climate changes, you may not get the right kind of temperature regime," Kittredge said.
Rock said that until the late 1960s, 80 percent of the world's maple syrup was produced in New England and about 20 percent came from Canada. "Today those numbers are exactly reversed."
There are fewer of the small New England family farms that used to generate much of the maple syrup, but the change in the climate has also contributed to the problem, Rock said. "Easily a third or more of the problem is temperature-related."