In his crusade to plant thousands of trees along streams in Pennsylvania, Dave Wise expected all kinds of obstacles.

But Wise, a Chesapeake Bay Foundation watershed restoration manager, never suspected that voles yes, those tiny, furry, mouse-like critters—would prove his most ferocious enemy.

Yet, there they were, swarming all over the farms he was trying to help, digging their sharp teeth into roots and killing about a third of his newly planted trees.

(Photo: Deb Nardone, Trout Unlimited)

After years of combat with the varmints, Wise and his colleagues concocted a defense. They installed plastic shields around the young trees and removed thick vegetation around the plantings. This deprived the voles of shelter.

The results have been as clear as the streams that the CBF is helping to clean. And about 95 percent of the trees are now surviving to act as natural filters to keep water pollution from flowing into the Chesapeake Bay.

"We started growing trees in grassy areas, and we met the devil he was a little brown furry guy called the vole," Wise laughs. "But now we've nailed that problem, and we've had great success. Forests are immensely important to water quality."

Over the last year, Wise and his fellow restoration experts at the CBF have helped to plant about 180,000 trees along streams in Pennsylvania. CBF is a partner in PA's Conservation Reserve Enhancement Program which has helped to plant 2.2 million streamside trees in Pennsylvania since 2000. This has involved 4,600 landowners and 2,175 miles of forested buffers. Similar stream restoration efforts are growing in Maryland, Virginia and across the Bay watershed.

Part of the goal is to stop manure from falling into streams by keeping cattle out of waterways. This often requires the construction of fences, and the digging of new wells to provide alternative water supplies for livestock.

Conservationists have long known that planting trees and bushes along streams helps prevent erosion.

But less well known is the fact that trees also stimulate important biological processes that remove pollution from streams, Wise said.

A 2004 study published in the Proceedings of the National Academy of Science found that forested streams remove 200 to 800 percent more nitrogen pollution which often comes from farm fertilizer, suburban lawns and sewage treatment plants—than streams with just grass along their banks. Streams lined with trees also have up to five times more aquatic life.

Riverbanks with trees are littered with leaves. When rain percolates through these leaves, the water brews a tea-like high-energy drink for creatures in streams. This feeds bugs and beneficial bacteria. They absorb nitrogen from the creek and use it as building blocks for their cell walls, ligaments and membranes. Thus, pollution becomes part of a mayfly instead of a "dead zone" in the Chesapeake Bay.

"Trees turn streams into huge nitrogen-processing facilities," Wise said. "Clean water factories is what they become."

CBF has been helping to build forested buffer strips in Pennsylvania for more than a decade. But the efforts have been accelerating in recent years as the Commonwealth has built one of the most successful CREP programs in the country.

Also key has been the Wise outwitting of voles. In part because of Dave Wise and his colleagues, the CREP program now reimburses farmers and landowners in Pennsylvania for the cost of controlling competing vegetation around newly planted trees for three or four years, to keep the voles from returning.

"That was the single biggest challenge of the whole program," Wise said of keeping the tiny mammals under control. "I'm still getting therapy for voles right now."

For more information, visit the CBF/Pennsylvania webpage.

Link: Stroud Study Proves Riparian Forest Buffers Work To Improve Water Quality

11/29/2008