Wildfire in the Tahoe Basin is an ancient presence, and a present menace. People living in the Sierra Nevada live in a landscape largely shaped by fire. Many of our western forests are suffering from being appreciated too much. In an effort to protect our forests, a national public/private policy of fire suppression was developed in the early 20th century, and shared by land management agencies, states, counties, communities and common citizens. As our scientific understanding of forests increased, we began to realize that fire has been one of the most historically important ingredients in overall forest health.
In the Tahoe Basin, most fires that burned over the centuries were small, but a few were big, and burned for perhaps months, only being extinguished by the snows of winter. Kindled primarily by lightening, this cycle continued for thousands of years, annually burning areas of hundreds, even thousands of acres. Because of these fires, the forests were mostly open and sunlit and had little in the way of woody buildup. But, that was before the Tahoe Basin we know today, with the density of urban development.
Over a century of suppression, forests became overgrown and their floors became covered in debris, resulting in diminished diversity, habitat and health. Droughts weakened many already stressed trees and beetle attacks accelerated tree mortality. We are left with a forest with many areas of dangerously high levels of dead, flammable material that surrounds homes, businesses and the people who reside and work here.
Many of our overgrown and fuel-laden forests can be returned to healthier, more natural and fire- tolerant conditions, but there is no easy fix, or quick, single solution. The job must be accomplished in stages, starting first where people, property and livelihoods are intermixed with the fire-prone forest. We call this the wildland-urban interface. The Tahoe Basin is mostly composed of this interface, surrounded by varying degrees of forest conditions. Some of the surrounding forests are twice as dense as natural conditions once produced, while others are at least eight times denser.
The first stage in tackling this job is to set priorities based on risk. Lives and property must be protected, and the areas with the greatest threat identified.
Various forms of treatments are applied to the lands on which a wildfire might approach. Handwork usually comes first. This work reduces the accumulations of burnable fuels on the forest floor. Then the ladder fuels are reduced. These can carry a fire up branches, like a ladder, into the trees. Thinning of small-diameter trees, either by hand or mechanically, opens up the canopy of the forest, reducing the unnatural densities and the potential of fire spread. The collected material, often called slash, is piled together in clearings and burned using controlled, safe methods. However, many of these slash piles are created, and there are only minimal opportunities that offer the right conditions to burn them safely and with acceptable air quality impacts. Another option for disposal of slash is through chipping. However, equipment availability and terrain factors can make chipping impractical. Moreover, the long-term effects of the heavy spreading of wood chips are still unknown.
Throughout the Lake Tahoe Basin, the USDA Forest Service has been conducting a variety of fuels reduction projects every year. In 2002, well over 1,000 acres were treated – an area the size of South Lake Tahoe’s Casino/Hotel area, including Edgewood Golf Course. Crews are well on the way to meeting the goals set for 2003. The Forest Service is not the only fire protection agency doing this work. Fire protection districts around the lake have been working on other projects as well. It’s a cooperative effort, with common goals – to create a set of community defense zones around vulnerable communities, to slow the behavior and spread of wildfires, and to increase the effectiveness of suppression.
Preventing serious wildfires and managing fire effectively can also help protect Tahoe’s water quality. If there was a very big wildfire in the Basin, large flows of ash-laden runoff could be unstoppable, leading to widespread contamination of the lake’s water.
Fire has both good and bad aspects. It is both an ancient presence, and a present menace. Yet it is a menace best faced with knowledge, resolve and mutual support.
To learn more about the dual roles of fire and hazard fuels reduction, visit www.smokeybear.com and click on the “Only You” section. To learn how you can contribute to wildfire defense through defensible space, visit http://www.unce.unr.edu/, and click on “Living With Fire.”
The Lake Tahoe Report 029
Air Date: 2003.08.19
Video Segment: USFS Fuels Management
Interviewees: Rex Norman (USDA FS)