A Good Burn
The Squamish Forest District in BC has started a controlled burning program which is expected to reduce the risk of wildfires and help trees grow.
By Paul MacDonald
In the end, a small part of the blame for some of the horrendous forest fires North America has seen in the last few decades falls squarely on the unlikely shoulders of two well known fictional characters-Smokey the Bear and Bambi. These cartoon characters convinced the public in a not so subtle fashion that all fires in the forest are bad, both through Smokey's declaring that "only YOU can prevent forest fires" and Bambi's mom dying in a forest fire in the much watched Walt Disney children's movie. In reality, however, fire has been part of the natural forest regeneration process for thousands of years. We've just managed to make it a villain in the latter part of this century. Julian Grzybowski, small business officer with British Columbia's Squamish Forest District, and forestry consultant and veteran fire boss Bob Gray would be the last people in the world to argue that uncontrolled wildfires, consuming thousands of hectares and costing the lives of courageous fire fighters, are not terrible and tragic events.
They want to see fewer of these types of fires. And that is exactly why the district, on Howe Sound just north of Vancouver, is choosing to fight fire with fire in a controlled burning program. Last year, the district carried out controlled underburning on a total of 70 hectares of partial cut areas-50 hectares in the spring, 20 hectares in the fall. And there are plans to do burns on a further 200 hectares in 2000. The primary goals of the program are ambitious-reducing the risk of wildfires, site preparation for seedling planting, brush control, nutrient cycling, enhancement of deer browse and enhancing fungal species which fight root rot.
The Squamish Forest District, 1.1 million hectares in size, encompasses part of the coast interior transition forestry zone, which has a mix of coastal and interior species, mainly Douglas fir and ponderosa pine. Even though this zone is on the traditionally wet West Coast, it is in fact characterized by water deficits during the growing season and high summer temperatures. A significant part of the district has had fire as the major eco logical process in the ecosystem. Frequent stand maintaining fires were in fact the norm prior to 1900. Since then, what may be viewed as "enlightened" human management of the forest has resulted in kind of a mess-a high density of stems, low tree vigor, high incidence of insect and disease and, arguably the most dangerous threat, an abnormal buildup of fuels on the forest floor. "A catastrophic, uncontrolled wildfire could result in the collapse of the entire ecosystem," explains Grzybowski.
In addition to reducing the risks to the forest ecosystem, the district also chose to carry out prescribed burns to increase the survival rate of the next generation of trees. Seedling survival is a challenge due to above mentioned drought conditions, brush competition and deer browsing. "In these particular sites, these are what we call firemaintained or fireformed ecosystems," says Grzybowski. "When you go back through time, even back to aboriginal management, fire was a tool that was used to get better berry crops, or better range for the deer." These days, the prescribed burns are intended to help knock the brush back and bring new trees-planted in the midst of leave trees-to the freeto grow stage quicker. Research on ponderosa pine in one of the areas, carried out by consultant Bob Gray, showed a fire return interval of about six years-until about 1900. "We looked at the makeup of the stands in the area and they were all even aged, about 80 to 100 years old," explains Gray. "From a natural perspective, this should not be happening.
We should have quite a different stand structure just from the dry nature of these areas." In practice what was happening was that all fires-even small fires which might have helped consume the dry fuels on the forest floor and aid in the decomposition process- were being put out. Any kind of fire was considered bad-no exceptions. "Fire can release the natural elements of an ecosystem and here we are suppressing fire like crazy because everyone is terrified by fire, we have this paranoia that all fire in the forest is bad," says Gray. "We know that fire can cause terrible devastation, but one reason we get that devastation is because we don't use fire management as a tool." It is a risk management situation-society is not willing to accept the risk and consequences that come with natural fires, but then society is to accept the risk and consequences of what will happen with unnatural fires, where fuel has been allowed to build up. "We've done such a good job of controlling fire to the point that we have upset the natural balance," notes Gray. "The result can be catastrophic fires like the ones we saw at Salmon Arm and Penticton in BC over the last few years."
Fuel accumulation is certainly a fact of life in the forests in the Squamish Forest District. There is a buildup of fine material on the forest floor and the area has a lot of small diameter, short trees that also represent fire fuel. In the first situation, decomposition only consumes a very small percentage of the material. In some of the dryer areas of the district, the decomposition rate is only a minuscule 1/100th of the accumulation rate, resulting in forest floor material building up at an extremely rapid rate.
"The only way you're going to achieve a stasis in that environment is when the fuel gets so deep that the trees can't get through that layer any more. If it was left, there would be no growth whatsoever ." The nuts and bolts of the prescribed burns at Squamish start with getting burning permit approval from both the Ministry of Environment, for air quality, and the Ministry of Forests, for safety and fire control. Advance work includes doing layouts and getting a detailed sense of the topography of the land. That high level of knowledge is readily available from Grzybowski and the staff foresters who know the district extremely well. "We lay it out so that we leave the trees that are likely to survive," explains Gray. "In terms of controlling the burn, we keep the fire in the block by managing the fuels adjacent to the block, such as putting a control line in." In some cases, that is quite simple. For example, in a burn they did last fall in high elevation Douglas fir, the top layer of materials was dry, but the duff layer below had a lot of moisture. "All we needed to do around the fire break was to get any dry materials out of the way and expose the carpet of moss and wet duff and that was sufficient. You basically want to provide a barrier to the spread of surface fire and also take into consideration the lobbing of embers from the fire area."
Embers are where wind and the weather enter the picture. Achieving a solid knowledge level of local winds in a burn area is one of the prerequisites in planning the burn. "That knowledge of local winds is important because winds can be your worst enemy. Things can really work against you when you've got a frontal system coming though kicking up winds of 50 kilometres an hour. That has the potential to blow things out of control." Each burn involves setting up a weather station, which measures critical data such as wind speed and direction. On the ground, crews will do detailed inspections in advance of the burn and physically remove deep accumulations of debris and fuel from the base of residual trees. Without this, these very valuable and healthy trees would be consumed or damaged by the fire. Special effort is made to control smoke as much as possible during the burn because the Ministry of the Environment has the power to subsequently shut down a burn if they receive complaints about the smoke.
At Squamish, the fire ignition crew, except for Gray, is made up entirely of foresters and forest technicians from the Small Business Program of the forest district. A suppression crew is also on hand, usually from the local First Nations band, equipped with chain saws and firefighting tools. The end result is the foresters on one side of the line with drip torches, carefully mapping and monitoring the burn, and the suppression crew armed with shovels and axes on the other side of the line, intent on seeing the fire does not get outside the mapped out block. For a large burn of 20 hectares, they will have an ignition crew of four and a suppression crew of six. Gray is the "fire boss" and directs both activities. Gray emphasizes that it is not just a simple matter of getting out there and lighting fires. In a burn they did last spring, they had three densities of leave trees in the block. "In order to make sure we didn't 'cook off' the crowns of the trees in one section, we had to make sure we kept the ignition strips fairly tight."
The ignition phase is time and labour intensive, as it can mean going back and forth across steep blocks that can be large- they did the 20hectare burn last spring in one day. "We'll ignite, check the progress, see how it's burning and if it's burning too aggressively, we'll slow it down. My job as burn boss is to monitor the fire overall, see how it's spreading and relay that information to the ignition crew." They will start igniting in narrow strips with short flames close to the fire guard and work into the block, essentially adding to the fire guard since fire won't go back over ground that is already burned. If there is a heavy accumulation of fuel on the forest floor, they may ignite an area and wait for it to burn down, perhaps 20 or 30 minutes. One of the strengths of the Squamish program, Gray says, is in the ignition crew and their knowledge of forestry and the ecosystem of the area. "When you start talking about meeting ecological objectives, they know exactly what you are talking about. You don't want just a bunch of robots out there with a drip torch doing, light, drip, walk, light, drip, walk. "We've got people that can read into what we want to do with the plan, apply it, and we are able to achieve better results."
Gray and Grzybowski both say that teamwork is truly key to the success, and safety, of the program. "When you consider what is at stake, it's very serious," says Grzybowski. "You need to have a very organized, well orchestrated team." Gray has done extensive prescribed fire burning with the US Forest Service and he notes that the ignition work there is never contracted out. "There's a reason for that. You know the people who are doing the work and you get consistency of application and you get the job done safely." With controlled burning, Gray says, the results speak for themselves, both in terms of uncovering the potential risk of wildfire in an area and the returns that will come down the road. "In one fire we did last April, we had what we call pretty good fire behavior at 7 p.m.
We were able to generate two metre flame lengths and pretty good rates of spread. And that's at night and in the spring. That should be a wakeup call. You can imagine the potential for fire that exists in August." Grzybowski notes that the program is still in its early stages and they will be closely monitoring the results. But he added there may be some tough decisions to make if they are going to follow the true historical make up of the ecosystem in the Squamish district. "It may involve changing our entire management objective," he explains. "If we're going back to managing for the ecosystem, then you're making a conscious choice about what species of wildlife and plant life are going to be there. There are certain species that are in there now that won't like it when the stand is more open. You're going to have the argument about whether they should have been there in the first place-and what you should do about it now."
The Squamish region has been the centre of controversy surrounding spotted owl habitat. "We have big issues around that. Spotted owls love this ground," says Grzybowski. "But we're not sure if they should be there at all. Is this their natural habitat? Or have they been opportunistic in invading the habitat as it evolved through fire suppression? This can have far-reaching implications on management in these ecosystems. "Owl habitat management, in its current form, will require continuation of fire suppression in order to avoid catastrophic fires. This policy will do nothing to rejuvenate ecosystems adapted to frequent disturbance. How long will it be until Mother Nature again demonstrates the impact of continual interference in the fire cycle?"
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