Agroforestry Can Reduce Interface Fire Risk

One of my last projects in a previous work life with the Research Branch of the BC Ministry of Forests was to design and set-up adaptive management trials testing forest restoration techniques in the Rocky Mountain Trench of Southeast BC in the late 1990s. The imperative for restoration in these forests (and also throughout the intermountain west of North America) was the tremendous structural and species composition changes that have developed in the last 75-80 years as consequence of fire suppression. The forests in question have evolved over 1000s of years with frequent (every 7 to 10 years) low-intensity fires. With the best of intentions (I believe there is a road to somewhere paved with these) we have put in place systems that have an enviable record in quickly putting down both human and naturally caused wildfire. Fire suppression has been carried out so efficiently, it has all but arrested this natural process on the landscape.

The result of quelling fires is what Dave White, a former colleague of mine in the Ministry who was tragically lost in a back country snow avalanche a few years later, termed “upside down ecosystems.” And “upside down” succinctly describes the modern forest composition in relation to its natural potential. What should be mosaic of grassland and forest patches has become a thick forest with small islands of grasses of much different composition. In areas that should predominantly be large old, thick barked, ponderosa pine with scattered Douglas-fir and lodgepole pine, has become a thick tangle of Douglas-fir and lodgepole suppressing new ponderosa growth.

The consequences of these forest changes are far-reaching and largely negative. Some timber has been saved from destruction until it can be cut, but the diminished quantity and quality of grassland has undermined wildlife habitat for everything from the charismatic macrofauna (a.k.a. elk) to the lowliest arachnid. Forage production is lost to the livestock industry and cattle and wildlife are forced into conflict over the remnants of the former North American savannah. Trees are abundant, but of poor form and low value. And in the ultimate irony, the risk of a catastrophic wildfire has grown immensely. Small trees, lower branches and woody litter that would normally be consumed over time in small, low-intensity burns, has built up to the point where fires can scale to the status of ‘fire storm’ in short order. Expansion of human settlement into these areas has also grown immensely, creating a high risk of interface fires sweeping not only through eight decades of unconsumed woody fuel, but also billions of dollars of homes, cottages, industrial development and public infrastructure.

And for anyone thinking this accumulation of forest biomass represents a great store of carbon to buffer climate change, I believe that is a false notion, because fire will release the stored carbon back into the atmosphere. And we can never put an end to forest fires. At some point the right combination of drought, wind and multiple lightning strikes will overwhelm the initial attack response and another major interface fire will occur. It is only a question of when. Managing the risk by reducing fuel loads in the interface is a logical response.

This week, Tom Hobby, Forest Economist at Royal Roads University rekindled the debate on the forest ingrowth problem with his well publicized report and interviews stating that we are not acting fast enough to reduce the risk of fires in these systems. The Filmon report commissioned after the interface fires in Barriere and Kelowna clearly outlined the scope of the problem and recommended action, and in academic/research circles we have known of the problem for decades.

A challenge however, lies in the scale of the problem. The Government of BC has started fuel reduction projects, but there are an estimated 1.7 million ha of interface areas at high risk of wildfire. The potential costs of restoring these areas could easily run into the $100s of millions. And there is also the issue of maintenance. The influx of housing, both permanent and recreational, means fire is a very risky tool to use, even in low-intensity controlled burns.

Fortunately, there are options through agroforestry that can reduce the fuel loads, manage the areas as fire breaks and mimic the structure of the natural forests. As an added benefit, adopting agroforestry practices on the landscape will generate income (through resource fees) and long-term jobs. A silvopastoral or forest farming approach in these ecosystems would involve retaining a low-density overstory of timber or Christmas trees in a single tree, widely-spaced grid pattern or clusters of trees with open spaces between. Often the lower branches of the trees are pruned to improve the value of the wood, but this also reduces ladder fuels to prevent ground fires from moving into the canopy. In silvopastoral systems livestock grazing on the grass, forbs and browsing of the shrubs provides an added benefit of annual removal of the fine fuels that can give fires an initial toe-hold. In both forest farming and silvopasture, the Crown can generate additional revenue from grazing licence, timber and non-timber resource use fees. This amounts to restoration that isn’t a drain on the public coffers, but instead generates jobs and income.

Supporting and developing agroforestry as a viable ecological restoration/economic development tool deserves serious consideration not only as a short-term fix before the inevitable happens again and millions or billions are lost in a major interface fire, but also as a permanent managed solution to the problem. Implementing solutions that simultaneously improve our environmental and economic bottom line is also overdue.