Our Dry, Warm Future may Favor Oaks

Posted by Jeff on Jun 11, 2016 @ 12:48 pm in Conservation | 0 comments | Last modified: June 11, 2016

Historically, many oak forests across the eastern U.S. experienced frequent low-intensity fires that promoted the establishment and growth of oaks. “However, fire and other disturbances have become less common,” says U.S. Forest Service scientist James Vose. “Red maple, tulip poplar, and other mesophytic, fire-sensitive, and shade-tolerant trees are increasing in many areas of the eastern U.S.”

But what does the future hold? Over the coming decades, changes in fire regimes, climate, and land use will continue to affect forests. However, new climate and disturbance regimes may actually favor oak forests, according to a new synthesis by Vose and Katherine Elliott, a U.S. Forest Service research ecologist.

Changes in precipitation regimes – the pattern and amount of rainfall and other precipitation – appears to be one of the factors favoring mesophytic tree species in eastern forests. Once established, oaks tolerate drought better than many non-oak species that are becoming common in eastern forests, such as maple, beech, willow, blackgum, and others. However, droughts were less common and less severe over most of the 20th century.

Along with a reduction in drought, fire and other disturbances have also become less common. Oaks are fire-tolerant, and although it’s unclear what fire’s future role will be, it will probably play an important role in shaping oak forests. “The combination of climate change, wildfire, and other disturbances could create environmental conditions that favor oaks,” says Vose.

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