Global warming may spur increased growth in Pacific Northwe...( CORVALLIS Ore. Global warming in th...)

CORVALLIS, Ore. Global warming in the next century could cause a significant increase in the productivity of high-elevation forests of the Pacific Northwest, a new study suggests. However, forests at lower elevations which in recent years have accounted for more than 80 percent of the region's timber harvest could face a decline in growth.

The potential changes, which are based on the projections of computer models, would be most pronounced in Washington. In that state, high-elevation forests could see their productivity increase substantially, from 35 percent a year to as much as 500 percent, depending on which climate scenario is used.

In Oregon, similar elevations might see more modest forest growth increases of 9 to 75 percent.

Overall, forest productivity could increase about 7 percent annually in forests west of the Cascade Range and 20 percent in forests east of them, in conclusions based on one climate scenario that largely reflects current trends of energy use, globalization and economic growth. However, management practices, genetic limitations, and changes in natural disturbances such as disease, insects and fire were not included in the study, and can also affect productivity.

These findings analyzed changes in forest productivity further into the future than most previous work, and were just published in Forest Ecology and Management, a professional journal, by researchers from the College of Forestry at Oregon State University and the Pacific Northwest Research Station.

"There's a lot of variability here, depending on which climate scenario turns out to be most accurate and what policy changes are made as a result," said Darius Adams, a professor of forest economics at OSU. "And there are dramatic differences in forest regions and elevations. Clearly the forest growth is likely to increase the most at higher elevations, but it's worth noting that those forests never had very high growth rates
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