Climate Change: Nearly Every United States Forest Threatened, Says Study

Even beyond the clear signs of drought in the West, forests from coast to coast in the United States are feeling the effects of climate change, as noted by a new study by individuals from 14 research institutions.

"While the effects have been most pronounced in the West, our analysis shows virtually all U.S. forests are now experiencing change and are vulnerable to future declines," James S. Clark, senior study author and Duke University's Nicholas Professor of Environmental Science said in a release. "Given the high degree of uncertainty in our understanding of how forest species and stands adapt to rapid change, it's going to be difficult to anticipate the type of forests that will be here in 20 to 40 years."

That's because increasing temperatures and uncertain levels of precipitation over the past 20 years have heightened drought severity across most of the continental 48 states, said Clark in the release.

The West is already seeing large-scale forest diebacks, infestation by bark beetles and wildfires--and several prediction models show that droughts will likely become more frequent, severe and lengthy across many of the states.

Climate may be changing more quickly than forest populations can move to new regions, too, according to growing evidence. As the weather becomes warmer and drier, tree populations, particularly those in Eastern woods, may fail to expand fast enough into easier habitats by dispersing seeds or through other natural methods, Clark said in a statement.

The study findings were recently published in the Early View online edition of the journal Global Change Biology. That report brings together conclusions from hundreds of studies and gives a summary of a report released earlier in February by several federal agencies and research programs.

"Prolonged drought affects wildfire risks, species distribution, forest biodiversity and productivity, and virtually all goods and services provided by forests, so there is a pressing need to know what is happening now, what might happen in the future and how we can manage for these changes," Clark said.

It's worth noting that forestry scientists and researchers currently have a pretty good idea of how individual trees are reacting to drought and climate change, Clark said in the statement. "But there's still uncertainty about what might happen at the species-wide or stand-wide levels, particularly in Eastern forests. These are the scales where we really need reliable predictions so forest managers can take steps now to help reduce large-scale problems."

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