Penn State professor of forest ecology and physiology, Marc Abrams , and Gregory Nowacki of the Eastern Regional Office of the U.S. Forest Service wrote a paper explaining how eastern U.S. forests are more sensitive to drought than before the 1800s.
In the paper published in the journal Tree Physiology , Abrams and Nowacki documented the changes in composition of the eastern U.S. forests over time and how these forests have been altered.
Abrams and Nowacki emphasized the importance on how the increase of drought intolerant trees are going to be affected in the future with climate change and the effects it will have in the surrounding land.
Most of the forests in the eastern part of the United States had evolved with organized fires, but since the time of European settlement and the advertising of Smokey Bear , the American mascot created to inform the public of the dangers of forest fires, the composition of the forests has changed dramatically, Abrams said.
“Most of the trees that are increasing in these forests are drought intolerant, which means the forests are changing in a way that is making these trees more vulnerable to drought, which is predicted in the future with climate change,” Abrams said.
Though climate change has not had as big of an impact on the eastern parts of the U.S., the dramatic change of these forests due to the lack of fire has caused for these tree species to continue to increase in the future, Abrams said.
“Some of the models for climate change say that the planet is going to get warmer and will therefore be susceptible to very severe droughts happening, and if that happens there is going to be a lot more mortality in these forests in the eastern U.S.,” Abrams said.
Some ways to help save these forests are to have prescribed burns, done by professional forest managers, Nowacki said.
The forests use to be filled with oak, hickory and pine trees, but have been in decline in the past years due to the lack of fire, Abrams said.
“With repetitive burning, oak and pine trees will be allowed to regenerate again over time,” Nowacki said.
These forests are now filled with maple and birch trees, which are “moisture loving” trees and are therefore sensitive to drought, Nowacki said.
“When fire is suppressed, maple tends to take over and they’re more sensitive to drought,” Lee Frelich , director for the University of Minnesota Center of Forest Ecology , said.
If the forests continue to become more drought sensitive and no action is made to help stop this, not only will there be a decline in tree species, animals living in those areas will also be in decline, Abrams said.
“We want to reverse the trend and use fire to rehabilitate the land,” Nowacki said.