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Forest thinning doesn’t always reduce fires

Brief by Allen Best

Forestry – October 2008 – Colorado Central Magazine

Thinning of forests near homes in areas hit hard by mountain bark beetles continues in communities along Colorado’s Interstate 70. But the experience in Summit County has been that making neighborhoods in these wildland-urban interfaces less susceptible to fire is expensive and not without counter-intuitive twists.

Consider this effect of thinning. The conventional wisdom is that removing the trees makes nearby homes safe from wildfire. But fire expert Ross Wilmore, of the U.S. Forest Service, told the Summit Daily News that removing dead trees allows more sunlight to hit the ground, thus encouraging grasses and shrubs to grow. When dried, this vegetation becomes “ladder fuels” that enable fires to climb into the tops of trees.

Such so-called crown fires are the most intense. This, said Wilmore, means that some lower-elevation areas will have moderate fire risks, instead of low.

The thinning is very expensive. In the last three years, chain-saw-wielding timber crews have “treated” -to use the word preferred by professional foresters -400 acres in locations considered of greatest danger if fires should occur. That leaves 8,600 acres to go.

The total cost of this future cutting, according to the Summit County Wildfire Council, is nearly $39 million. The county government figures it can find $13 million, but hopes to get a county tax increase approved that will yield another $6 million in the next 12 years.

The wood is worth relatively little. A new mill in Kremmling, about 40 miles away, makes pellets for burning in stoves. However, the Daily News story suggests that the mill’s rate of $10 to $20 per ton won’t defray much of the cost.

The U.S. Forest Service is willing to pay $1,500 to $2,000 per acre for tree removal, but the actual cost is estimated to range from $4,500 to $8,000 an acre.

As they have for several years, representatives from the I-70 corridor have gone to Washington D.C. to argue that the beetle epidemic requires more federal aid.

“I don’t think the federal government fully understands how much of a national issue this is, and we’re going to raise their attention,” State Rep. Christine Scanlan told the Daily.

Scanlan asked for federal appropriations during the next three years of $200 million, about half to be devoted to wildfire mitigation, with the balance to be used to cut down trees that threaten existing structures or threaten public safety. Trees falling into powerlines could disrupt electrical service, she says.

Another legislator, State Sen. Dan Gibbs, said $200 million falls far short of what is needed. “We need to get more federal funds earmarked for Colorado,” he told the Summit Daily News. Gibbs in the past procured $1 million for logging operations, plus other state funds for thinning projects in municipal watersheds that wouild be adversely affected by fire.

The epidemic, which is traced to 1996, is briskly turning most of the lodgepole pine forests in northern Colorado a rusty red. Forestry officials warned in January that 95 percent of lodgepole pine in the state will be dead within five years.