* Threatened Icons
* Forests across Western U.S. face increasing insect, fire risks

Travel east on the North Cascades Highway, and you’re likely to see acres of thin, gray spires poking out of the forest near Rainy and Washington passes.

The road may be closed for the winter, but U.S. Forest Service research biologist David Peterson clearly remembers how sad the dead lodgepole pines look.

Many are victims of infestations by the mountain pine beetle. Once red and dying following a feed fest by the beetle’s hungry larvae, the lodgepole pines’ needles have since fallen off, leaving the now-dead trees naked and exposed. The beetle population’s recent, explosive growth is partly attributed to a warmer climate, which allows them to thrive and speeds up their reproduction.

“If you look close, there are dead trees everywhere,” said Peterson, who is a member of a statewide group looking at how Washington’s forests could be affected by climate change. “I’ve watched it spread over the last seven to eight years going up North Cascades Highway. There’s thousands of dead trees there.”

Scientists warn that they don’t know enough to give one definitive answer as to why these infestations are happening. But one realistic explanation is that forest soils are being dried by a one-degree average global temperature increase in the past 50 years. Warmer, drier conditions are stressing trees, which makes them more susceptible to infestations by insects such as the mountain pine beetle, the spruce beetle and the hemlock looper.

“I’d be reticent to say that’s a sign of climate change per se,” Peterson said. “But it’s a sign of stressed forests for sure. If you look at the trend across the West, there are much higher levels of insect activity in the last 100 years.”

State forest entomologist Karen Ripley calls some of the region’s insect activity, such as the widespread pine mountain beetle attacks on high-elevation white bark pine forests near White Pass, “quite unprecedented.”

Skagit County’s beetle situation, however, isn’t as dramatic as elsewhere. While the state found 16,971 Skagit trees killed by the mountain pine beetle in 2006, Eastern Washington had more than 4 million in 2004. And British Columbia is experiencing North America’s worst-ever pine mountain beetle outbreak.

The Canadian government estimates that 80 percent of the province’s marketable pine will be dead by 2013.

If climate change continues, increased insect activity is just one of many possible threats for Washington’s iconic forests.

If the area experiences several years of consecutively longer and warmer summers, local forests are bound to respond. In some places, the forest is already responding. One example is at Skagit Valley College’s Mount Vernon campus, notes Jon Vanderheyden, Mount Baker-Snoqualmie district ranger for the U.S. Forest Service.

The tops of tall western cedar trees there and elsewhere in the county are dead, a possible result of stressed trees getting less moisture during the drier, warmer summers, Vanderheyden speculated.

Dead and dying forests have another risk: fire. Already, past management practices — mostly a hands-off approach that has left many public forestlands overgrown with small trees and underbrush — have created forests rife with fire hazards. Add longer, warmer summers and area forest managers say the region could see more frequent and larger wildfires in the future.

The dangerous combination of mountain pine beetle and fire was obvious in 2006, when the massive Tripod Complex Fire burned 175,000 acres in Okanogan County. The fire, which cost more than $82 million to fight, easily blew through large swatches of forest that had been struck by beetles.

“Dead and dying trees would provide a continual source for forest fires,” said John Keller, a private forest steward for the state Department of Natural Resources who has experience fighting wildfires. “Under those kinds of situations, we could have much greater difficulty controlling forest fires.”

Larger fires are already happening.

The average number of acres burned each year on land the state of Washington protects has increased from 6,000 in the 1970s to about 30,000 in the first seven years of this decade, the DNR reported this spring. A 2006 study by the Scripps Institution of Oceanography showed that throughout the American West, the key factor in the average number of large wildfires quadrupling since 1986 was a warmer climate.

Some tree species may not fare well here as climate changes. Temperature increases could throw long-established tree zones, based on latitude and elevation, off kilter.

In the 1980s, the Forest Service found it could not replant some of its traditional seed stock in southern Oregon’s Rogue River-Siskiyou National Forest because of a local shift to a drier climate there, Vanderheyden said.

“Normally you want to get tree seedlings that are grown from seeds collected here because it would be best adapted,” Peterson said. “People are starting to rethink that. Maybe you should start to get seedlings from a location that’s farther south that would be more tolerant.”

Here in northwestern Washington, Peterson speculates that tree stands in lowland forests might decrease if dramatically drier weather reaches the lowland forests where they grow.

That includes the drought-tolerant Douglas fir — one of the region’s most commonly logged and economically important tree species. Other species, such as the grand fir and big leaf maple, are also at risk, Keller said.

While lowland trees may suffer, others in higher elevations could benefit. Cold snowpack on mountain -tops typically limits plant growth there, but warmer temperatures could decrease snow cover and help some species expand their range. Mountain hemlock and subalpine firs for example, could grow more, Peterson said. And tree lines may climb higher, Vanderheyden said.

And in some circumstances, higher carbon dioxide concentrations in the atmosphere could help trees. But Jeremy Littell, a member of the Univeristy of Washington’s Climate Impacts Group with a research background in forestry, said that while extra carbon dioxide could aid photosynthesis to a point, other limiting factors such as water availability and soil quality could offset that benefit.

Peterson is betting his family’s future on changes in area forests. For the past six years, he and his wife have planted 3,000 young trees on their 20-acre private forest near Lake Cavanaugh. Instead of planting a solid forest of just one species as some traditional foresters do, he’s experimenting with what he calls adaptive management.

He specifically sought seeds collected from trees in Island County, which is generally drier than Skagit, thinking their seedlings would be more likely to survive a warmer climate here. Peterson also intermixes different species to create more biodiversity, which may help his forest’s overall health. And he’s trying to match each patch of land with trees best suited for its particular environs.

In moisture-rich parts of his property, Peterson planted wet-loving species like western red cedar and Sitka spruce. And on drier land, there are more drought-tolerant species, such as Douglas fir.

In many cases, he’s found his young trees are growing faster than usual. Fingering the needles of a tall, 6-year-old Douglas fir, Peterson said the tree was growing healthily because it was planted in the right spot — a sun-soaked, west-facing slope.

Sierra Pacific Industries, a California-based timber company that opened a softwood lumber mill near Burlington last year, is already using some of the same techniques Peterson promotes. The company, which owns about 80,000 acres of forestland in Skagit County, plants a mixture of tree varieties together and plants tree species best suited for each specific site. But company spokesman Mark Pawlicki said he isn’t sold on the idea of shifting tree seed zones.

Instead, Sierra Pacific is trying to make its forests more sustainable by increasing the volume of timber produced per acre. The company is doing this by selecting seedlings known to grow quickly and by thinning forests of weaker trees to promote healthier stands.

But Paul Kriegal, resource manager for Goodyear Nelson Hardwood Lumber Co. Inc. of Bellingham, doesn’t expect to change his forest practices anytime soon. His company, which owns about 3,400 acres of forest that’s mostly in Skagit County, has “always believed in species diversification,” Kriegal said. But he said Goodyear Nelson doesn’t plan on making drastic changes until bigger timber corporations like Sierra Pacific try it first.

“Some of us are probably a little on the skeptical side,” Kriegal said. “Foresters, as a rule, are a little more conservative. I’m not looking for a tropical forest anytime soon.”

Peterson doesn’t expect drastic changes in Western Washington’s forests, either. Just how area forests will react to climate change is far from certain, but Peterson is confident Washington won’t lose its evergreen identity.

The abundance and location of some species may fluctuate, but he said Western Washington forests should essentially remain intact. And the forests of Eastern Washington, where rain is already sparse, are likely to feel the brunt of climate change before we do. To help offset some climate change, he said locals can protect forests now.

“The one thing Skagit County can do is we can store carbon in these forests,” Peterson said. “Every time you permanently lose a forest to a housing development, to a Wal-Mart, to a golf course or whatever, that carbon is lost forever.”

Peterson said locals can protect their forests by supporting site-specific scientific research while also experimenting with different management practices now.

“If we assume there could be some effects, then we are motivated to take some action now,” Peterson said. “We have a lot of examples in history of prices being paid if we wait too long to make decisions. ... So let’s get rolling and at least develop some plans that will help us adapt.”

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* Franny White can be reached at 360-416-2148 or .