What should be done to reduce the threat of catastrophic wildfire at Lake Tahoe?
What should be done to reduce the threat of catastrophic wildfire at Lake Tahoe?
08 May 2011
published by www.rgj.com
USA: Legislators from Nevada and California identify catastrophic fire as the primary threat to the Lake Tahoe regional ecosystem and Lake Tahoe’s fabled clarity.
In response, federal policymakers have allocated $300 million from the Southern Nevada Public Lands Management Act to manage forests, restore watersheds and give to the local government in the Tahoe Basin.
How will this money be spent?
This guide will help you sift through the relevant issues and options.
Take some time to familiarize yourself with the history of the problem and the range of options on the table, then visit OurTahoe.org and sign-up to discuss these options with other concerned citizens.
The Sierra Nevada forest evolved with fire as a natural part of the ecosystem.
Until the early 20th century, fire usually occurred in five- to 25- year cycles, burned at low to moderate intensity and could last for months.
Lightning or Washoe tribe members, who used fires for management purposes, usually ignited the fires. These fires created open stands of fire-tolerant pines such as ponderosa, sugar and Jeffrey.
Tahoe forests were also populated by fire-adapted species like the thick-barked Sequoia.
In 1894, naturalist John Muir described the view: “The trees of all of the species stand more or less apart in groves, or in small irregular groups, enabling one to find a way nearly everywhere, along sunny colonnades and through openings that have a smooth, parklike surface.”
Muir’s “parklike” forests changed with the introduction of logging in the late 19th century. The discovery of the Comstock Lode in Nevada created a high demand for timber beams to shore up mineshafts for silver.
With no major timber supply available in the deserts and grasslands of Northern Nevada, attention turned to the Lake Tahoe Basin. Loggers cut the largest, most valued trees, which consisted of large stands of pines. This left less fire resistant trees, such as the White fir, standing.
Logging left many forests across the West vulnerable to fire. The Great Fires of 1910 in Idaho and Montana burned more than 3 million acres and killed 86 people. The event helped defined the early policy of fire suppression for the U.S. Forest Service.
Federal forestry officials responded to public demand for fire protection by initiating an aggressive firefighting program. By the 1930s, its mission included protecting timber losses for the logging industry and preserving forest health.
Dubbed “the 10 a.m. policy,” fires were to be extinguished by 10 a.m. the day after discovery. In 1918, the largest fire burned 1,013 acres in the basin.
After 110 years of fire suppression, Tahoe’s forest is out of balance with natural fire conditions, said Elwood Miller, former executive director of the Nevada Fire Safe Council. The basin historically supported about 60 trees of similar size per acre, compared to today’s 460 trees that range in sizes. Dense forests composed of highly flammable trees have replaced Muir’s “sunny colonnades.”
Today, Tahoe has one of the highest ignition rates in the Sierra Nevada and ranks high in fire frequency and intensity, said Norb Szczurek, division chief of the North Lake Tahoe Fire Protection District.
In recent years, the U.S. Forest Service has added fire suppression to its national fire management policy. In large part, this means managing the amount of “fuel” — dead trees, underbrush and dense forests — that might be ignited in a forest fire.
The Forest Service breaks fuels down into four categories:
* Crown: The branches and foliage in the tops of trees.
* Ground: The decaying plant material that lays between the soil and leaf and needle litter.
* Ladder: All medium-sized trees and shrubs that provide a “ladder” to the crowns of tall trees.
* Surface: All small shrubs, dead branches, fallen trees, leaves and grasses.
Often identified as the most hazardous fuels in forests, they allow fire to spread across the landscape.
The objective of fire and forest mangers for the basin is to create a defense zone that’s a minimum of a quarter mile wide in the 21,614 acres that separate the urban residential areas from wildland fuels.
Local policymakers are considering four options for reducing forest fuels. Each has costs and benefits, consequences and trade-offs. Each also has supporters and detractors.
No proactive fuel reduction, rely on firefighting.
Communities rely on firefighters to suppress fires. Assuming no catastrophic fires, this is a cheap solution. But it also entails a high risk because the likelihood of a fire occurring is high. Because this option leaves dense and highly flammable forests, the risk of a catastrophic fire would remain high.
Those who support this option might say: More trees are better. This is a cost-effective solution if no fires start.
Those who oppose this option might say: The forest is in an unnatural condition and under stress with high concentrations of trees and seedlings, saplings, shrubs and herbs causing insect infestation and disease. A high risk of fire ignition exists from either humans or lightning strikes.
The $14 billion of real estate in Lake Tahoe’s Basin needs protection. Fighting wildfire is more expensive than fire management if you include property loss, forest restoration and public health. The clarity of Lake Tahoe may be affected.
The potential exists for someone to die in a fire. Smoke from a wildfire is potentially dangerous to children and the elderly, and it releases carbon into the atmosphere.
Crews of 10 to 20 people use chainsaws to remove dense stands of smaller diameter trees (up to 14″), and low hanging branches. This can reduce ladder and crown fuels in densely forested areas on steep slopes and areas that are environmentally sensitive. Hand thinning cannot remove large-diameter trees. Trees are cut down, piled and burned or chipped and spread on the ground. Spreading the material on the ground could inhibit the growth of seedlings, saplings, shrubs and herbs by limiting soils access to moisture and air. Spreading this material could also prevent soil erosion by creating a buffer against rainfall. Depending on the experience of the crew and the parcel size, hand thinning can cost $400 and $2,500 per acre.
Those who favor this option might say: It is the most responsive to high slope and sensitive environmental zones. This can be the least expensive option if the areas are large and inmate crews or private crews are hired.
Those who oppose this option might say: It is ineffective at removing ladder fuels that exceed 14″ in diameter. A high risk exists for human injury. This is the most time consuming, labor-intensive treatment.
Crews use hydraulically driven equipment to remove trees. Crews either chip and spread materials back onto the forest floor or remove them entirely. Timber removal can reduce carbon and nitrogen content from the soil. This strategy costs $2,500 to $5,000 per acre depending on the parcel size and crews hired. And these machines can only be used in forests with mild terrain, which is about 30 percent of the forest.
Those who support this option might say: This is the most effective and fastest way to remove fuel. It has a low risk of injuring people. It also is easier to schedule and can be done in summer and winter.
Those who oppose this option might say: It has a negative affiliation with timber industry and is an excuse for more logging. Soil could be compacted which impacts its ability to absorb water and can increase water runoff.
Temporary roads could have to be built, possibly leading to erosion problems. Typically, this is the most expensive option. The machinery disturbs wildlife when running. Tree stumps and scarring leave the forest unattractive.
Crews mimic natural fires by burning in designated areas. Trees and branches are piled up, seasoned and burned, or crews can burn areas which have already been thinned. Burning the forest might increase nitrogen concentrations in the water, and the smoke could be related to algae. It is designed to reduce high-risk wildfire behavior. Costs are $400 to $1,500 per acre, depending on the area to be treated and the crews hired.
Those who support this option might say: It imitates the natural fire ecosystem, which existed prior to European settlement. The risk is low that it will hurt the ecosystem, unless the fire escapes. Fire managers can prescribe conditions under which they want to burn, unless the weather shifts suddenly.
Those who oppose this option might say: Scheduling is difficult because of weather, seasons and air-quality restrictions. It’s hard to do in areas with a lot of fuel load, and might need to be repeated. Fire could escape, which is troubling in urban areas.
And it’s expensive. The smoke could be dangerous to children and the elderly. It also releases carbon into the atmosphere and nitrogen into water sources. The forest is left visually unattractive.
Agee, J.K. 1993. Fire Ecology of Pacific Northwest Forests. Island Press, Washington, D.C.
Cobourn, John. Water Resource Specialist. Video interview in February 2007 at the University of Nevada Cooperative Extension, Incline Village, NV.
De Lasaux, Michael and Kocher, Susan D. Fuel Reduction Guide for Sierra Nevada Forest Landowners, University of California Cooperative Extension.
Fire Effects Information System
Gruell, G. E. 2001. Fire in Sierra Nevada Forests: A Photographic Interpretation of Ecological Change Since 1849. Missoula, Mont.: Mountain Press Pub. Co.
Holl, S. 2006. Effects of Fuel Reduction and Forest Restoration on Wildlife in Lake Tahoe’s Wildland Urban Interface. A report to Tahoe Regional Planning Agency.
Miller, Elwood. Advisor to the Nevada Fire Safe Council. Video interview in February 2007 at the University of Nevada Reno Reynolds School of Journalism.
SNEP, 1996. An Overview of Fire in the Sierra Nevada. Sierra Nevada Ecosystem Project. Davis, California.
Smith, Ed 2004. Living with Fire: In the Tahoe Basin. University of Nevada Cooperative Extension, Minden, NV.
Smith, Ed. Natural Resource Specialist. Video interview in February 2007 at the University of Nevada Cooperative Extension, Reno, NV.
Stephens, S.L. and J.J. Moghaddas. 2005.Experimental Fuel Treatment Impacts on Forest Structure, Potential Fire Behavior, and Predicted Tree Mortality in a California Mixed Conifer Forest. Forest Ecology and Management 215 (2005).
Szczurek, Norb. Division Chief. Video interview in February 2007 at the North Lake Tahoe Fire Protection District, Incline Village, NV.