July 6, 2014

Wildfires and controlled burns...

Last year there was a huge fire in our area, the Rim Fire. A vast area in the Sierras was turned into a blackened wasteland. 257,314 acres were burned.

And what drives me crazy is that it was totally unnecessary. The way to prevent wildfires is well known. I personally learned of it in the 1960's. What is it? "Controlled burning."

From Wikipedia: Controlled or prescribed burning, also known as hazard reduction burning (HRB) or swailing, is a technique sometimes used in forest management, farming, prairie restoration or greenhouse gas abatement. Fire is a natural part of both forest and grassland ecology and controlled fire can be a tool for foresters. Hazard reduction or controlled burning is conducted during the cooler months to reduce fuel buildup and decrease the likelihood of serious hotter fires.[1] Controlled burning stimulates the germination of some desirable forest trees, thus renewing the forest. Some cones, such as those of Lodgepole Pine and Sequoia, are serotinous, meaning they require heat from fire to open cones to disperse seeds.

Wildfires are not natural. They only happen when a lot of fuel accumulates. Fallen leaves and needles, dead trees and fallen branches, and areas that have become choked with vegetation. The fuel builds up for decades, and and when it burns it is like nuclear bombs going off. The eara where the Rim Fire happened had not burned since 1989.

But in nature forests burn every few years. These fires are usually what are called "cool fires," because not much fuel has accumulated since the last fire. They are ground fires, that move erratically, burning along the ground, but not igniting healthy trees. The results are more open forests, instead of dense thicketty ones.

These kinds of fires can be produced intentionally. The pictures below were taken by my daughter, when she drove through Groveland recently. Notice that among the dead trees, vegetation is returning. Suppose, in 3 or 4 years, in say May, when things are still fairly cool and moist, fires were lit in the area. They would not be catastrophic wildfires, because there wouldn't be enough to burn. Patches of dried vegetation would burn, dead plants would burn, but it would be too soon, and too early in the year to result in a "hot fire." And if you kept doing that every 3 or 4 years, you would never have a hot fire. The fuel would never get a chance to gather.

Rim Fire, fallen tree

Rim Fire area, near Groveland

Rim Fire area, dead trees

Posted by John Weidner at 7:25 PM