GRANTS PASS, Ore. — Scientists predict that lodgepole pine — one of the most common trees at higher elevations in the Cascades and Rockies — will be largely gone from the Northwest by 2080 due to the warming climate.
Richard Waring, emeritus professor of tree physiology at Oregon State University and co-author of the study, said Monday that warming temperatures are eliminating spring frosts that keep other trees from competing with lodgepole and are creating more welcome conditions for bark beetles that have killed millions of pines in Wyoming and Colorado. Warmer temperatures will mean less moisture in the soil, even without changes in rainfall, allowing species such as Douglas fir to move in.
"Some of this is not based on just computer models. It is a real comparison of climate that has already changed since the 1980s," Waring said. "The good news is they are growing better," for the time being, due to less frost. "The bad news is they are more vulnerable to insect attack in some cases."
The study plugged data from 12,600 research plots into computer models that took into account factors such as growing season, snowpack runoff, soil wetness, and summer temperatures. The results were tested against changes already observed since 1980 and projected into the future based on climate models. The area covered by lodgepole pine decreases only slightly by 2020, then decreases more rapidly as young trees fail to replace older ones that die.
By 2080, lodgepole would remain on less than 6,000 square miles in North America, about 17 percent of its current range, the study said. A quarter of that area would be new habitat for lodgepole, primarily in northern British Columbia. Lodgepole will remain common in very cold places such as Yellowstone, where it is the dominant species.
Lodgepole pine is a pioneering species, one of the first to move into areas scorched by fire or covered with pumice after a volcanic eruption. Some of the cones open to release their seeds only after they have been burned. The species extends at higher elevations from the southern Sierra Nevada north through the Cascades of Oregon and Washington to British Columbia and the Yukon. In the Rockies it is found from Colorado through Wyoming, northern Idaho and western Montana into Alberta.
In the Rockies, beetles have killed 5,550 square miles of lodgepole pine and spruce forest since the late 1990s, prompting Agriculture Secretary Tom Vilsack to allocate $35 million for tree removal.
Lodgepole pine was commonly used by American Indians for teepee poles. It is less valuable for timber than species like Douglas fir and ponderosa pine, though it is finding new use as a fuel to convert to pellets to burn for heat and electricity.
Dominick DellaSala, chief scientist for the Geos Institute, a forest policy group, said the study is consistent with other research into the changes the nation's forests are going through as temperatures get warmer and rainfall patterns change.
DellaSala added that as wildfire is expected to increase with warming temperatures, lodgepole pine may get a break because it is better adapted to fire than other species.
The study was funded by NASA and the Natural Sciences Engineering and Research Council of Canada. It appears in the latest edition of the journal Climatic Change.