By Seth Truscott, College of Agricultural, Human & Natural Resource Sciences
DAVENPORT, Wash. – Along a blustery rural highway, foresters from Washington State University and the U.S. Department of Agriculture are proving that living snow fences – windbreaks made of live trees – can protect Northwest roads and farms from winter’s fury.
More than a decade ago, a group of WSU, state and federal researchers planted the Davenport Living Snow Fence, two 880-foot double rows of Rocky Mountain junipers designed to catch wind and snow along Highway 25 just north of Davenport, Wash.
Ten years later, the scientists returned, measuring poles in hand, to see how the wall of junipers had fared. They discovered that, contrary to popular belief, living snow fences can thrive in Washington’s drylands.
Proper preparation, varieties important
Living fences are common in the Great Plains, where winters are frequently harsh and drifts topping 30 feet close highways. The Davenport fence was planted to show that Plains-style windbreaks can grow well in areas with less than 16 inches of annual rainfall.
“There was a belief that trees wouldn’t grow here,” said Don Hanley, an extension forester and emeritus professor with the WSU School of the Environment. “We knew that was wrong. People were using the wrong stock, and they weren’t planting or maintaining them correctly.”
To change that, he, Gary Kuhn and Dennis Robinson, now-retired foresters with the USDA’s Natural Resources Conservation Service, enlisted help from the Washington State Department of Transportation to find a snowdrift-prone stretch of Highway 25.
Working with a cooperative landowner, the Washington Department of Fish and Wildlife and the local Lincoln County Conservation District, the foresters laid down tough polypropylene weed-blocking fabric, planted a hardy strain of junipers – and waited.
“We had good stock that was planted correctly and good site preparation,” Hanley said. “We put everything we had into it perfectly. And the trees grew, and grew, and grew – with no irrigation. ”
Growth measured at 5 and 10 years
Hanley, Kuhn and Robinson measured the windbreak at 5- and 10-year marks, then shared their findings in “Davenport Living Snow Fence Demonstration: A 10-year Survival and Growth Update,” a technical bulletin published in December by WSU Extension. Read it at https://pubs.wsu.edu/ItemDetail.aspx?ProductID=15815&SeriesCode=&CategoryID=&Keyword=Living%20Snow%20Fence.
They found that the trees had crown closure – they had grown their branches together to form a complete wind barrier – in five to six years.
“With a live snow fence, you want them to close quickly, so they can start doing their job,” Kuhn said.
“Growth has been tremendous,” Hanley said. “More importantly, it’s been observed by thousands of people driving that highway.”
Benefits of snow fences
“Living snow fences are like an insurance policy,” said Kuhn. “About every 10 years or so, we get bad winters in Washington. When we do, roads are closed and people have big problems.”
Living fence benefits are widely documented, Hanley said. The trees keep roads clear of snow, making them safer while minimizing the expense of plowing. They help homes and barns stay warmer, saving on heating costs.
Windbreaks shelter barns, pastures and livestock pens, for example, protecting newborn calves from cold while saving on feed costs – cold livestock eat more. Windbreaks also keep valuable topsoil from blowing away in the wind.
Live fences require less maintenance than their wood or metal counterparts, while also providing cover for wild birds. Increased plantings of windbreaks could benefit the Northwest’s conservation nursery industry, Kuhn said.
The Davenport fence is expected to live for at least another 25 years with little maintenance. Knowledge gained from the experiment has helped develop other living fences near Anatone, Wash., and Athena, Ore.