Forest tour looks at strategies to thin trees, resist wildfires

JOHN HOLLAND jholland@modbee.com

I ambled with a tour group last week across a slope near Pinecrest that had grown thick with trees.

Researchers with the U.S. Forest Service talked about how best to thin these woods so they resist wildfire. The work also could provide logs for sawmills while enhancing wildlife habitat and a watershed that supplies Modesto and other locales.

Forest managers have done thinning for decades, leaving trees more or less evenly spaced across many acres. The project described last week creates much more variety, in patches as small as a quarter-acre. Some are open ground. Some are well-spaced trees. Some are left as thickets for the benefit of wildlife that prefers such habitat.

The researchers said the woods looked like this for millennia because of frequent, gentle fires resulting from lightning or Native American land management. Then came the 20th century and the policy of putting out every fire as soon as possible. The result was a fuel buildup that brought on infernos like the Rim Fire of 2013.

I touched on this research in a story Wednesday that mainly was about bark beetles killing millions of drought-stressed trees. I’m expanding on it in this week’s Farm Beat column because of the connection between Sierra Nevada forests and farming in the Valley below.

Forest thinning could increase runoff by 9 to 16 percent, according to research cited by Steve Brink, vice president for public resources at the California Forestry Association. Less water is taken up by the tree roots, he said, and more makes its way to streams and aquifers.

“Snow-catch is also a big deal,” Brink said, referring to white stuff that can evaporate from the upper limbs. “We want the snow to be on the ground and not in the canopy of the trees.”

The research took place on 27 acres at the Stanislaus-Tuolumne Experimental Forest, used since the 1920s to study logging methods and related topics. Because of fire exclusion, the site went from an average of 127 trees per acre in 1927 to 299 in 2007, ecologist Eric Knapp said.

The project involved intentional burning of some patches when conditions were right, along with logging that produced enough timber to build about 600 typical houses. The Stanislaus National Forest carried out the work with Sierra Resource Management, a company based in Jamestown.

Some of that lumber could supply homebuilders in and near Stanislaus County who are finally coming out of their nearly decade-long slump. And having a more fire-resistant forest could please flatland folks who don’t care to see massive fire scars while visiting Pinecrest Lake or the Dodge Ridge ski area.

The tour included members of Yosemite-Stanislaus Solutions, a coalition of environmentalists, timber industry people and others concerned about the national forest and adjacent national park.

Some of the green groups not in the coalition remain skeptical of forest thinning. I spoke by phone this week with Chad Hanson, director of the John Muir Project at the Earth Island Institute, who said large fuel buildups and wildfires like the Rim Fire are part of the natural process.

“They weren’t all low-intensity and small,” he said. “They were also high-intensity and large.”

His group, based at Big Bear Lake in San Bernardino County, argues that many wildlife species benefit from the dead standing trees and downed logs left amid the surviving trees after a blaze. National forest timber sales might require that some of these features be left, but Hanson said it is not enough.

The debate will go on, and I will be happy to travel again to cover it in Tuolumne County, where I used to live and work. It has long been part of The Bee’s coverage area, because so many flatlanders visit there and rely on its water and other resources.

John Holland: 209-578-2385