As you drive around the Pacific Northwest or other regions, have you ever noticed that the makeup of the forest changes when you drive from region to region, gain or lose elevation, or cross over a mountain pass? This phenomenon is real, and it happens due to microclimates. Scientists at three Northwest universities took this logic the next step, theorizing that as climate change occurs, it could push the forests themselves to change. These hunches are confirmed in a new study announced today by Oregon State University:

In a new report, scientists outline the impact that a changing climate will have on which tree species can survive, and where. The study suggests that many species that were once able to survive and thrive are losing their competitive footholds, and opportunistic newcomers will eventually push them out. In some cases, once-common species such as lodgepole pine will be replaced by other trees, perhaps a range expansion of ponderosa pine or Douglas-fir. Other areas may shift completely out of forest into grass savannah or sagebrush desert. In central California, researchers concluded that more than half of the species now present would not be expected to persist in the climate conditions of the future.

According to Richard Waring, professor emeritus and a lead author of the study, many such changes are already happening. “In some cases the mechanism of change is fire or insect attack, in others it’s simply drought,” he said. “We can’t predict exactly which tree (species) will die or which one will take its place, but we can see the long-term trends and probabilities. The forests of our future are going to look quite different.”

The complete study, “Predicting satellite-derived patterns of large-scale disturbances in forests of the Pacific Northwest Region in response to recent climatic variation,” can be downloaded as a PDF if you click the link.

Photo: The defoliation from major epidemics of bark beetle infestation, such as these in these stands of lodgepole pine in British Columbia, reflects the challenges that tree species across much of the West face as climate changes and threatens their future ability to survive. (Photo courtesy of Oregon State University)