Region faces declining snowpack

In recent years, declining snowpack and increased wildfires have been prominent features in the ecological story of Sisters Country - but is there a connection between the two? And how does climate change fit into the picture? These questions, and others, were discussed in Sisters at last week's "Science Pub" sponsored by OSU-Cascades.

With an official lecture title of "Waning Winters and the Interconnected Effects of Snow and Wildfire," Oregon State University Geoscientist Anne Nolin presented some of her findings on the subject at Three Creeks Brewing Co. in Sisters.

With a Ph.D. in geography from University of California, Santa Barbara, Dr. Nolin is a professor at OSU's main campus in Corvallis, where she has been on the faculty since 2002.

Nolin's presentation addressed trends of warming and cooling in the West, primarily during the last half of the 20th century. In summary, she said that we are now seeing "less snow and more rain." As an example, she stated that nearby Santiam Junction has seen a 70 percent drop in snowfall over the last seventy years, even though total precipitation has increased slightly during that same period.

She reported that snowfall - and snowpack - "in the low to mid-elevation range is especially vulnerable." Mid-elevations were defined as being in the 3,600- to 4,300-foot range. Regarding the effects of the forests on the snowpack, Nolin talked about what she termed the "moisture subsidy," which is especially important in higher-elevation forests, that is, forests at elevations above 5,000 feet.

Most precipitation in the Cascades falls in a relatively short time, with the peak coming in December and January. Comparatively little falls during the rest of the year, so the snowpack acts as a reservoir that nurtures the forests for the remainder of the year. In turn, the snowpack (and its moisture subsidy) that sustains the forest during drier times is also directly dependent on the forest to sustain the snowpack itself.

This cycle of mutual dependence can be seriously disrupted by the effects of fire. Nolin reported that 65 percent of western fires have occurred in the seasonal snow zone. Without tree cover to shade and cool high-elevation forests in the wake of winter snowfall, the forest becomes warmer; and the snow - together with the forest's moisture subsidy - disappears sooner.

"There is a very direct correlation between temperature and fire," said Nolin, "and more fire means less snow."

In addition to less shading effect, the burned forest hastens the snowmelt by virtue of the charred ash that continues to slough off the burned trees. The ash darkens the snow, causing it to absorb more heat from sunlight and melt even faster.

Skiers skiing through the burned local forests may have noticed a black substance building up on their ski tips. This is an indicator of the presence of charred forest debris that settles on the surface of the snow and causes the accelerated heat absorption.

This deposit of charred debris continues for many years after a fire. The extra heat absorption may result in loss of the snowpack more than three weeks earlier than would otherwise have been the case.

"Snow matters for vegetation," said Nolin.

She also pointed out that the old trees, in the forests that have burned, germinated under entirely different climatic and precipitation conditions than we have now. As a result, she said, the vegetation that grows in the future may not be the same as the forest it is replacing. This factor is already spurring necessary changes in modern silviculture, making studies such as Nolin's all the more important.

Christine Coffin is director of communications and outreach at OSU-Cascades. As such, she coordinates the school's Science Pub program.

"This is our fourth year of doing them, and we modeled them after the Science Pub program at our campus in Corvallis," she said. "There's a genuine interest in science and research in the community, and we try to present topics of interest to Central Oregon."

This is the third time that the Science Pub program has been staged in Sisters.

"To date, about 2,600 people have attended these presentations in Central Oregon," Coffin said.

OSU-Cascades is in the process of expanding to a full four-year college. "We have this '4' campaign going on, and about a dozen businesses in Sisters have volunteered to be '4 Central Oregon' ambassadors," said Coffin. "They share their excitement with their employees and customers. That lets legislators know that the community is behind this."

Science Pub topics are carefully selected to appeal to community members. "The great thing is," said Coffin, "that Science Pub tries to attract science presenters who can talk to the lay person."

The OSU-Cascades Science Pub series will continue next month on Tuesday, April 16, at the Sunriver Homeowners Aquatic & Recreation Center. The topic will be "Why is the Deschutes River So Peculiar? The Curious Case of Cascadian Rivers." This view of the Deschutes River will be presented by research hydrologist Gordon Grant. For information on the Science Pub series, log on to OSUcascades.edu/sciencepubs.

For information about the 4 Central Oregon campaign, log on to www.OSUcascades.edu/4.