Climate change may alter forest balance in ozarks archives power outage houston txu


The Ozarks has been forested for 35 million years, said Cindy Sagers, who teaches plant ecology and plant biology at the University of Arkansas in Fayetteville, and who is a member of the governor’s commission. She expects a forest will survive in the region in some fashion, but it won’t be the Ozarks of today.

Models put together by the National Wildlife Federation forecast temperature increases of as much as 7 degrees Fahrenheit for Missouri by 2100 if global warming goes on unchecked, and that would “alter the composition of the state’s forests, with southern pines replacing oak and hickory currently prevalent in southern Missouri and the Ozarks.”

“If conditions become drier, the current range and density of forests could be reduced and replaced by grasslands and pastures,” the EPA report on Missouri noted. “Even a warmer and wetter climate could lead to changes; trees that are better adapted to warmer climates, such as (some) oaks and southern pines, would prevail. Under these conditions, forests could become more dense.”

A third analysis, this one in 2006 by Jacqueline Mohan, then a scientist with the Marine Biological Laboratory at Woods Hole, Mass., noted that rising carbon dioxide will lead to the proliferation of vines such as poison ivy and Japanese honeysuckle in forests around the country.

Because these plants don’t have to generate the wood structure to support them the way a tree does, they grow much faster. Poison ivy grew twice as fast in an environment simulating projected CO2 levels at mid-century compared to poison ivy exposed to today’s levels of the gas. Not only was it growing faster, but the plant’s oil that causes skin irritation was more potent.

Doug Inkley, senior scientist with the National Wildlife Federation, said all of the models for the region under global warming indicate rising temperatures, but less certain is the rainfall forecast. Less rainfall would lead to the drier Ozarks, while more rainfall would lead to the expansion of the range for southern pine species, for example, he said.

In a wetter future, species of trees now associated with Louisiana, for example might migrate northward, such as southern magnolia and live oak, which is most often seen draped with Spanish moss, said Shannon, with the Arkansas Forestry commission.

Jerry Presley, a forester who rose to become a former director of the Missouri Department of Conservation, and who now works as a consultant for the Missouri Forest Products Association, said he is skeptical of computer models that predict dramatic change.

Part of the problem with envisioning the forests of the Ozarks is that the region has never been static. There is no baseline model for what the region should look like. The Ozarks has continually weathered temperature extremes and climate change, say these experts.

Twenty thousand years ago, during the last ice age, glaciers pushed south and much of Missouri was covered by spruce-fir forests similar to Canada. As recently as 8,000 years ago, the climate was warmer and drier than it is today, more hospitable to plants and animals found in places such as New Mexico and Arizona. Only in the last few thousand years has the climate in the region been comparable to today’s.

Each of these periods has left its fingerprint in terms of trees and other plant and animal species that still survive in the region, sometimes only as islands, like the coves of beech that Sagers noted can still be found in the Arkansas’ Ozarks, or as outliers on the far limit of their range, like the ashe juniper found in colonies in southern Missouri. It is a relative of the cedar that is more common in Texas.

Dennis Figg, wildlife program supervisor with the Missouri Department of Conservation, said it is impossible to tell how the Ozarks will evolve under climate change because many of the models are continental or global in scale and it is difficult to localize them to a region or a species.

Nevertheless, his agency is trying to anticipate climate change such projects as restoration of bottomland forests in parts of Missouri. They are no longer are just reforesting with trees that were historically there, but those that might thrive in a future altered by climate change.