Climate Trivia: Transition Zone Transition?
The area around Vermont’s Green Mountains is a “transition zone” between the boreal forests in Canada, which are dominated by conifer species that are better adapted to the extreme winter cold, and the broadleaf forests that are familiar to residents of the eastern U.S. Higher elevation areas of the Green Mountains are significantly colder and windier than the lower zones. Higher elevation areas have traditionally been dominated by conifer species that form communities resembling the boreal forests. Pine trees dominate at higher elevations while oaks and maples dominate at lower elevations.
Trivia Question: As temperatures have warmed over the past 40 years, the area of the Green Mountains dominated by pines has:
a. shrunk
b. expanded
c. remained about the same
The correct answer is a. A two degree Fahrenheit warming and a 40 percent increase in precipitation in the region over the past 40 years has corresponded to shrinking of the area dominated by conifer trees and range expansion of the less cold hardy broadleaf trees. The area of the mountains dominated by broadleaf forests increased by 19 percent.
Seasons: Winter, Spring, Summer, Fall
Source: Beckage, B. et al. “A rapid upward shift of a forest ecotone during 40 years of warming in the Green Mountains of Vermont.” PNAS 105 (2008): 4197-4202.
