Agroforestry Can Reduce Interface Fire Risk
by George Powell
Fire suppression and other land management has changed the forests of western North America.
In a previous work life I was a researcher with the BC Ministry of Forests. One of my last projects was to design and set-up adaptive management trials testing forest restoration techniques. The imperative for the restoration was the tremendous structural and species composition changes that have developed in the last 75 to 80 years. And these changes have been brought about as consequence of fire suppression.
Upside Down Ecosystems
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. And 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 wildfires. 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 a former colleague of mine 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. A forest with small islands of grasses of much different composition. These areas should be large old, thick barked, ponderosa pine with scattered Douglas-fir and lodgepole pine. But they have 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. The habitat loss has impacted everything from the charismatic macrofauna (a.k.a. elk) to the lowliest arachnid.
Forage production is also 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.
Increased Risks of Big Fires
Small trees, lower branches and woody litter should normally be consumed over time in small, low-intensity burns. But it 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. This creates a high risk of interface fires sweeping through eight decades of unconsumed woody fuel. It will also now take billions of dollars of homes, cottages, industrial development and public infrastructure.
Climate Change Implications
And for anyone thinking this accumulation of forest biomass represents a great store of carbon to buffer climate change, I have bad news. Fire suppression to store carbon is a false notion. Because fire will release the stored carbon back into the atmosphere when fire eventually occurs. It is a carbon store, but not a stable carbon store.
How Do We Manage the Risk?
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. In his well publicized report and interviews, he stated 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 it recommended actions. And certainly in academic and 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.
Agroforestry is a Solution
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.
Managed Systems that Mimic Nature
A silvopastoral or forest farming approach in these ecosystems would involve retaining a low-density overstory of timber or Christmas trees. These would be arranged in a single tree, widely-spaced grid pattern or clusters of trees with open spaces between.
In agroforestry systems the lower branches of the trees are often pruned to improve the value of the wood. And 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 via the annual removal of the fine fuels that can give fires an initial toe-hold.
Fire Management that Generates Revenue
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. Instead, it 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.
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