Tahoe Donner forestry work slowed Interchange Fire | SierraSun.com

Tahoe Donner forestry work slowed Interchange Fire

Greyson Howard
Sierra Sun

Greyson Howard/Sierra SunA field of brush has been pulverized, or masticated, into chips and small limbs, which serve to slow a fire's progress.

Walking through the different stages of Tahoe Donner’s forest fuel reduction, from pulverized brush to new forest plantations, it quickly becomes evident why the Aug. 22 Interchange Fire stopped where it did.

While a swift multi-agency response from both ground and air was able to stop the 80-acre fire from entering Tahoe Donner, fire crews were able to make a stand at the fire’s northern flank because of the 6,000-home subdivision’s extensive forestry work.

The fuels treatment essentially accelerates a natural process, turning dense brush back into open forest, said Ben Gwerder, Tahoe Donner’s assistant forester. Bill Houdyschell, the subdivision’s head forester, said the adopted goal is open forest because a recent study showed that fire burns four times faster through brush than forest.

“This burned in the same place as the 1960 Donner Ridge Fire, which changed it to brush,” Houdyschell said. “We are trying to get the forest back.”

Gwerder said brush is naturally replaced by forest when saplings grow large enough to shade out the bushes and grass, but the Tahoe Donner foresters have taken a number of steps to hasten the transition.

Houdyschell said crews use a variety of methods to eliminate the brush, including piling and burning, mastication (grinding up brush and leaving it on the ground), and the occasional use of a commercial herbicide.

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The area reached by the recent Interchange Fire had been tractor-piled and burned, Houdyschell said, but mastication is also effective because it drops the fuel to the ground and reduces oxygen exposure.

Herbicides, Gwerder said, have to be approved by the Lahontan Regional Water Quality Control Board, and are designed not to disperse, affecting only broad-leafed plants.

Once the brush is removed, trees are planted at 10-foot spacing in plantations, he said.

Despite all these human manipulations, Houdyschell said they try to keep things looking natural.

“We started with the roads and worked out in a patchwork of treatment blended into the natural topography and setting ” we try to make it look right,” Houdyschell said.

Gwerder said the natural fire interval for the Tahoe Donner area would be every 10-to-15 years, but because of the extensive residential development, such a cycle obviously cannot be allowed.

In 1960, the Donner Ridge Fire burned almost 45,000 acres, Houdyschell said, reaching from the current interchange fire site to the state line, and the 2003 fire, also in the same area, burned between 70 and 100 acres.

Because brush is the first thing to grow back after a fire, each burn means starting from scratch for the foresters, he said.

“We’ll have to see what burned and plan what we can and can’t do next year to get the forest going again.