CLIMATE CHANGE FOR EASTERN US: Dr. Marc Abrams, Penn State Professor of Forest Ecology and Tree Physiology, continued to share what he has seen in research in the area over his 40 years in the field.

“Forest composition in the eastern US has been changing quite dramatically during the last century. The main change has been an increase in shade tolerant and mesophytic (middle moisture) trees, such as red maple (the #1 increaser), followed by black birch, tulip poplar, blackgum, and others. Species like hemlock and beech would also be increasing if not for problems with hemlock woolly adelgid and beech bark disease. These increases have been to the detriment of oak, hickory, and pine trees. My research has found that the main driver of this change is not climate change but is the suppression of fire starting with Smokey the Bear legislation in the 1930s.

“…Greenhouse gases and climate change have impacted fall colors in some positive and some negative ways. While the increase in red maple is bad for the sustainability of oak, hickory and pine forests, it is one of our brilliant fall leaf color species. In addition, the longer growing season and increased CO2 are increasing photosynthesis and therefore the leaf pigments that produce the brilliant fall colors. However, the timing of peak colors is now about 5-14 days later than it was about 40 years ago when I first started carefully observing year-to-year variation in fall colors. In New England, peak colors are coming about two weeks later in most years.”

Abrams did share a warning as well, noting “We should not be dismissing the future potential impacts of climate change. The eastern US has been lucky so far.”