Eastern forests shaped by Native Americans' burning than climate change – ScienceDaily

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Native Americans' use of fire to manage vegetation is now the Eastern United States has been more profoundly understood, according to Penn State researcher who has determined that forest change composition in the region has caused more

"I believe Native Americans were excellent vegetation managers and we can learn a lot from them about how to best manage the U.S.," said Marc Abrams, a 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, need to burn the forest understory regularly."

Over the last 2,000 years at least, according to Abrams forests – frequent and widespread human-caused fire resulted in the predominance of fire-adapted tree species. The time has been curtailed, forests are changing, with species such as oak, hickory and pine losing ground.

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

Not this phenomenon does not apply to other regions, Abrams noted. In the western U.S., for example, climate change has been much more pronounced than in the East. That region has received much more warming and more drought, he explained.

"Here in the East, we have had a slight increase in precipitation that has ameliorated the warming," said Abrams.

To learn the drivers of forest change, to investigate novel approaches, to analyze both pollen and charcoal fossil records with tree-census studies to compare historic and modern tree composition in the forests of eastern North America. They looked at seven in the middle of the eastern United States. Those forest types two distinct floristic zones – conifer-northern hardwood and sub-boreal to the north, and oak-to-south.

The present-day pollen and tree-survey data revealed significant declines in beech, pine, hemlock and larches, and increases in maple, poplar, ash, oak and fir. In forests to the south, both evidence tree and polls focus on historic oak and chestnut and increases in map and birch, based on present-day data.

"Modern forests are dominated by tree species that are increasingly cool-adapted, shade-tolerant, drought-intolerant pyrophobes – trees that are reduced when exposed to repeated forest burning," Abrams said. "Species such as oak are largely promoted by low-to moderate-level forest fires. Furthermore, this change in forest composition is making eastern forests more vulnerable to future fire and drought."

Researchers also included 2,000 years, bolstering their findings, which were recently published in the Annals of Forest Science. The result of the early 20th century. Moreover, it appears that low numbers of Native Americans were capable of burning large areas of the eastern U.S. and did so repeatedly.

After 1940, they found, fire suppression was an ecologically transformative event in all forests.

"Our analysis identifies multiple instances of fire and vegetation changes that are likely to be driven by human population shifts beyond those expected from climate alone," Abrams said. "After Smokey Bear came on the scene, we were paying a big price for that change." – and we need to get back to that middle ground in terms of our vegetation management. "

Gregory J. Nowacki, with the Eastern Regional Office, U.S. Department of Agriculture Forest Service. Penn State's Agricultural Experiment Station funded this research.

Story Source:

Materials provided by Penn State. Original written by Jeff Mulhollem. Notes: Content may be edited for style and length.

. [TagsToTranslate] Trees; Nature; Invasive Species; Forest; Exotic Species; rainforests; Early Climate; Archeology; Early Humans

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