Research looks into 400 years of Pennsylvania’s forests, which have been ‘completely transformed’

By Marcus Schneck
Researchers at Penn State and other universities investigate historic influences on modern forests.

While forests of the northeastern U.S., from Pennsylvania north to Maine, may hold mostly the same tree species as they did 400 years ago, significant differences emerge under closer inspection.

“If you only looked at a tree species list, you’d have the impression that Northeast forests haven’t changed,” explained Jonathan Thompson, research associate at the Smithsonian Conservation Biology Institute. “But once you start mapping the trees, and counting them up, a different picture emerges. In some ways the forest is completely transformed.”

While forests of the northeastern U.S., from Pennsylvania north to Maine, may hold mostly the same tree species as they did 400 years ago, significant differences emerge under closer inspection.

“If you only looked at a tree species list, you’d have the impression that Northeast forests haven’t changed,” explained Jonathan Thompson, research associate at the Smithsonian Conservation Biology Institute. “But once you start mapping the trees, and counting them up, a different picture emerges. In some ways the forest is completely transformed.”

The researchers found that farming was the most significant factor in today’s composition of the forest. If more than half of a town was farmed, the local forests likely have changed considerably from their colonial-era selves.

But, even as the composition of the forests changes, the forest as a landscape type is resilient across the region and, short of significant human development, will return to that state, explained David Foster, director of the Harvard Forest.

Source: Research looks into 400 years of Pennsylvania’s forests, which have been ‘completely transformed’ – pennlive.com, 2019-11-21

Eastern forests shaped more by Native Americans’ burning than climate change

By Jeff Mulhollem
Native Americans’ use of fire to manage vegetation in what is now the Eastern United States was more profound than previously believed, according to a Penn State researcher who determined that forest composition change in the region was caused more by land use than climate change.

“I believe Native Americans were excellent vegetation managers and we can learn a lot from them about how to best manage forests of the U.S.,” said Marc Abrams, professor of forest ecology and physiology in the College of Agricultural Sciences. “Native Americans knew that to regenerate plant species that they wanted for food, and to feed game animals they relied on, they needed to burn the forest understory regularly.”

Over the last 2,000 years at least, according to Abrams — who for three decades has been studying past and present qualities of eastern U.S. forests — frequent and widespread human-caused fire resulted in the predominance of fire-adapted tree species. And in the time since burning has been curtailed, forests are changing, with species such as oak, hickory and pine losing ground.

“The debate about whether forest composition has been largely determined by land use or climate continues, but a new study strongly suggests anthropogenic fire has been the major driver of forest change in the East,” said Abrams. “That is important to know because climate change is taking on an ever larger proportion of scientific endeavor.”

Source: Eastern forests shaped more by Native Americans’ burning than climate change – Penn State University, 2019-05-21