The Growing Risk of Wildfire

Recently unmanageable wildfires have destroyed forests in Australia and the United States costing billions of dollars. Does a similar fate await B.C. Many foresters say yes.

The Growing Wildfire Threat into B.C.: How to Sustain’s Ecosystems, Economies, and Society

Canadian Silviculture Magazine Summer 2002 by B.A. Blackwell and R.W. Gray

Over the past two decades millions of hectares have been damaged by wildfire in the United States due to conditions similar to those now occurring in BC. TheUS fires have resulted in significant human and economic losses, and have cost taxpayers billions of dollars to suppress. The US put in place a $1.2 billion annual fuels and forest health management program. Without similar preventative intervention, a similar fate may await BC.

Since 1994, the U.S. has seen 15 million hectares burned in wildfire, thousands of homes lost to fire in the wildland-urban interface, forty fire fighter’s lives lost, and $4.5 billion spent on the direct suppression and immediate rehabilitation of wildfires (United States General Accounting Office 1999). The escalation of wildfire activity has been defined as a crisis, and has been associated withhas been associated with a loss of ecosystem health and stability.

Between 1988 and 1999 the National Forest Health Monitoring Team inventoried over 9.5 million hectares of forestland mortality caused by insects, disease, air pollution, and abiotic factors (United States Department of Agriculture National Forest Health Monitoring Team 2000). In addition to current attack levels, the Team has documented that another 24 million hectares nation wide is at risk to insect and disease attacks.

These elevated levels of insect and disease attacks, and increased wildfire activity over the past two decades have partially been attributed to the impacts of long-term fire suppression; this has been well documented in the literature (Mutch 1994, Society of American Foresters 2000). The U.S. has embarked on an ambitious program of fuels and forest health management in response to what researchers believe is a ”brief window of opportunity”, spanning 15 to 30 years, for effective and aggressive action before uncontrollable, catastrophic wildfires become widespread (Covington et al. 1994).

The U.S. government plans to address 1.25 million hectares per year, of National Forests alone, with mechanical, manual, and prescribed fire treatments. Congress has appropriated $12 billion over the next 10 years to fund the planning and implementation of treatments. As of June 3, 2002, the natural resource managers in the U.S. have prescribed burned 500,000 ha.

Are these problems applicable to British Columbia? That is the question that many fire managers and foresters are currently asking. In B.C., many ecosystems in the southern half of the province have more in common with ecosystems of the Pacific Northwest than they do with the rest of Canada. Similar to the U.S., the dry Interior forests of B.C. have been negatively influenced by the interruption of historic fires. In many of these ecosystems, fire suppression has resulted in excessive tree ingrowth into forest stands and encroachment into areas that were historically grasslands.

Associated with the processes of ingrowth and encroachment is a growing accumulation of both surface and overstory fuels. Increased fuel loadings and changes in forest structure result in a shift away from forests that were previously influenced by low severity surface fire, to forests where high severity stand replacement fires are now the norm. This shift in fire severity has many negative ecological consequences including increased nutrient losses, altered soil properties, destruction of below ground flora and fauna, and an overall long-term loss of site productivity.

The ecological outcomes of high severity fires are in great contrast to the historic low severity surface fires, which typically resulted in a nutrient flush, a vigorous plant response, and limited net change in soil properties and site productivity.

Associated with fire suppression related changes in forest structure is the increased incidence of insects and disease. Higher stocking levels have resulted in increased competition for moisture and nutrients, which typically has increased tree stress and hence susceptibility to attack. Over the past decade we have seen a dramatic acceleration in the attack levels of Douglas-fir bark beetles, Spruce Budworm, and Mountain Pine Beetle throughout British Columbia. In many stands higher insect attack incidence levels can be attributed directly to changes in stand conditions associated with fire suppression in combination with successive mild winters.

The current Mountain Pine Beetle epidemic in the central interior of the Province has been linked to global climate changes, but there has been limited discussion regarding the ecological changes associated with a changing fire regime. It would appear that protecting pine forests from fire has shifted the successional pathway of these forests so that they are potentially more susceptible to the Mountain Pine Beetle.

Other important considerations include changes in wildlife habitats and species distribution guilds. The open condition of many of the dry interior forests has been significantly altered by the changes in composition and structure outlined so far. This has impacted both the quality and quantity of available habitat for those species that depend on these types of forest and has caused a species shift, allowing species that are adapted to closed forests to expand into what were historically open forests.

The current fuels and fire management dilemma that we face in B.C. can be attributed to a lack of public awareness, and our poor understanding of ecological change associated with resource management practices over the past 50 years. Awareness has been heightened by the efforts of the Auditor General’s reporting on ”Managing Interface Fire Risk” and Provincial government initiatives to create a Wildland Fire Act, however the scale and level of effort required to address the complexity of these problems is daunting.

It is apparent that management of forests must shift to an ecosystem-based approach that integrates an improved understanding of historic disturbance regimes, structure, function, and forest composition. In addition to an improved understanding, large scale application of fuel treatments are required to reduce the current landscape-level risk of catastrophic fire in many parts of the Province. Land managers in B.C. must re-introduce prescribed fire as a viable fuel treatment alternative. The re-introduction of prescribed fire will not be easy and will require a significant shift in public, private sector and government attitudes toward prescribed fire.

In addition to developing an improved understanding of the problem and the appropriate treatments, new tools and applications are required to assess risk and prioritize treatment. Tools such as the Wildfire Threat Rating System (Hawkes and Beck 1997) and improved fuel and fire behavior modeling are required.

The cost of planning, designing and implementing these treatments will be significant but as demonstrated in the U.S., the cost of ignoring the problem will be significantly greater through the loss of human life, public and private property, and the opportunity cost of resources foregone.

Covington, W.W., Everett, R.L., Steele, R., Irwin, L.L., Daer, T.A., and A.N.D. Auclair. 1994. Historical and anticipated changes in forest ecosystems of the Inland West of the United States. Jor. Sus. For. 2(1/2):13-63.

Hawkes, B.C., Beck, J., and Sahle, W. 1997. A wildfire threat rating system for the McGregor Model Forest. Final report submitted to the McGregor Model Forest Association, Canadian Forest Services, Project 3015, Victoria, B.C.

Mutch, R.W. 1994. Fighting fire with prescribed fire: a return to ecosystem health. Journal of Forestry 92:31-33

Society of American Foresters.

United States General Accounting Office. 1999. Western National Forests: a cohesive strategy is needed to address catastrophic wildfire threats. Report to the Subcommittee on Forests and Forest Health, Committee on Resources, House of Representatives. Washington, D.C.