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Dying trees: Forests at risk By Vickie Aldous Ashland Daily Tidings Hills throughout southwestern Oregon are dotted with the reddish-orange of dead and dying conifers, evidence of a steep increase in tree mortality. The widespread tree deaths have sent many woodland owners looking for help. "I'm fielding a lot of calls and walk-in visits from concerned property owners who are having trees die on their property," said Max Bennett, a forestry agent for the Oregon State University Extension Service's office in Central Point. "There has definitely been a huge spike in mortality over the past year. It's a pretty dramatic one." Red-colored pines killed by beetles dot a sparse mix of other trees and vegetation in the Ashland Watershed above Lithia Park. In the region, forestry officials have seen a huge spike in the number of dead trees. Ashland Daily Tidings/DENISE BARATTA Deaths of ponderosa pine jumped in southwest Oregon from 417 trees in 2001 to 20,986 trees last year. Douglas fir deaths in the region rose from 321 trees in 2001 to 32,148 trees in 2002, according to Ellen Goheen, a U.S. Forest Service plant pathologist who helps conduct aerial surveys for tree mortality in the Rogue, Illinois and Umpqua Valleys and surrounding foothills. The Forest Service and Oregon Department of Forestry have been conducting the annual aerial tree mortality surveys since 1951. Increased tree mortality usually occurs in pulses in response to drought and other adverse conditions, according to Goheen. The 2003 tree mortality survey will begin in mid-July, when the needles of newly dead trees will have turned red, she said. The 2000-01 drought is partly to blame for the tree die-off, Goheen and Bennett said. The National Weather Service measured just 9.63 inches of rain for the water year that began in September 2000 and ended August 31, 2001. The normal rainfall level is 18.86 inches for the water year, according to the weather service. Overstocking of tree stands after decades of wildfire suppression also have left the conifers competing for water, nutrients and sunlight. The stressed trees are at increased risk from insect infestation, Goheen and Bennett both said. "The combination of drought stress and overstocking led to the sharp increase in mortality," Goheen said. "It takes about a year from when the insects find the trees to when they turn red and show up in the surveys." During the annual mortality surveys, researchers look for the tell-tale signs of red in the forests below as they fly in a clear-nosed airplane. They then check conditions on the ground to improve the accuracy of the aerial count, according to Goheen. The hardest hit areas are at 3,500 feet elevation and below, she said. That means valley and foothill residents, including those in Ashland, have an up-close look at the problem. "Over the past year, we've had a lot of Douglas fir mortality in the lower areas of the Ashland Watershed in the interface between town and the upland forest," Bennett said. "If you drive on I-5 and look at Ashland, you can see a ring of red trees." That same ring is evident around many local communities, he said. The Ashland Forest Lands Commission currently is working on a proposal to thin trees from city-owned lands in the watershed. Historically, frequent, low-intensity wildfires would have thinned out forests, reducing stress on surviving trees. In their own way, insects are thinning overstocked forests, but not in a way most humans would prefer, Goheen said. "They are not necessarily taking out the trees we would choose to remove," she said. "A lot of backyards are becoming sunny places." Many invading insects, especially pine bark beetles, also prefer large trees with thick bark that provide a protected, moist environment for larvae growing in the inner bark zone, she said. Most humans prefer to keep large trees - not only for aesthetic reasons but because of their resistance to fire - while thinning small diameter trees and brush that carry wildfires into crowns, a practice known as thinning from below. "The insects are thinning from above," Goheen said. And unlike wildfires that consume much of the flammable material in a forest, insects leave behind the dead trees. "Our biggest concern is that there is a lot of dead material on the hillsides," Goheen said. Property owners with dead trees should consider removing the material to reduce wildfire risk, while keeping in mind fire season restrictions that limit chainsaw use, according to Bennett. Some dead trees on the landscape provide valuable habitat for wildlife, with larger trees being most useful, he said. People can help trees that are still alive. "Once trees are successfully attacked, there's not a lot that can be done. Landowners need to focus on prevention - thinning, clearing out brush and deep watering," Bennett said. About every two weeks, thoroughly soak a conifer's root zone, being careful to avoid watering too near the trunk, he advised. The amount of time a tree should be watered depends on the soil texture, he said. Oaks and madrones are adapted to dry conditions and should not be over-watered during the summer. Frequent waterings can promote root disease, according to Bennett. This year's wet spring may have helped alleviate drought stress on surviving trees, but a dry summer and fall could have an impact, Bennett said. Regardless of changing weather patterns, many trees will continue to suffer because of overstocking in much of the valley, according to Goheen. "We're seeing a lot of trees dying on the hillsides right now," she said. "I expect we will be mapping Douglas fir and pine mortality this year." 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