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Test thinning of trees underway in Lost Lake Park

Experiment may become part of strategy for wildfire prevention

Chainsaws haven’t been heard in the Spruce Grove area of Lost Lake Park for almost 40 years, but they were falling trees again this week – only this time the goal is to save the forest.

With funding from the municipality, a crew is cutting in three small second-growth areas of the park, testing different densities and approaches to find a balance for fire suppression purposes, wildlife values and aesthetic beauty.

"Nobody’s done this kind of thinning before, this is completely new territory for everybody," said Bob Brett of Snowline Research, who is a consultant for the project.

While the trees in the area grew naturally following clearcutting in 1965, there’s nothing natural about the stand of forest where the test thinning is taking place, according to Brett.

In a natural forest, the density of trees is about 300 to 400 big trees per hectare, with other smaller trees growing under the canopy. In a modern plantation, where a forest is cut and replanted, the density is about 800 to 900 trees per hectare, with periodic spacing to keep the number of competing trees down.

In Spruce Grove, one area had a density about 14,000 stems per hectare, while other areas had between 4,000 and 5,000 stems. In the event of a wildfire the result would be that these dense stands of trees would burn intensely and allow a fire to spread quickly from tree top to tree top.

The forest is also too dense to allow for shrubs and bushes, reducing its value for wildlife.

Bruce Blackwell, a fire suppression consultant and biologist for the project, says there are literally hundreds of hectares in Whistler that fit this pattern, including some areas that are located near residential neighbourhoods. If thinning is one of the treatments recommended by Whistler Fire Services when it tables its wildfire prevention and suppression plan, then this test will help determine how that thinning is carried out.

The dense forests were also identified as a wildlife issue in the Whistler Environmental Strategy.

"Thinning should help to reduce the crown fire potential, by spacing out the crowns and by lifting them off the ground a little further. Spacing should help the trees to grow a little faster as well," said Blackwell.

"It will also be easier for the firefighters to fight a fire. You can imagine if this section caught fire without the thinning, you couldn’t get anywhere near it. If it’s properly spaced, it spreads slower, it’s easier to contain. You could drive a pump truck or a foam truck in if you needed to."

The test areas are different from conventional thinning for several reasons. The first is that workers will be hauling out all of the cut trees rather than leaving them as potential fuel on the forest floor.

Another difference is the fact that they are taking out the more valuable coniferous trees, leaving deciduous tree species that are shorter lived, are more resistant to drought and are more fire resistant. They are also leaving clumps of trees, which will be better for wildlife and aesthetic values.

"Right now we’re experimenting with the density, 45 per cent, 35 per cent and 25 per cent crown closure. Each one will let in different amounts of light, which will determine how the understory vegetation grows and what the potential will be for wildlife," said Blackwell.

"It has a random look, unlike a plantation. We’re also hoping it will add old growth characteristics to the area almost immediately, something that could take 50 years to realize if this forest was left alone."

The test densities will also help the municipality determine what the costs will be if they have to thin hundreds of hectares in municipal parks. By testing three different densities, all of which require a different amount of manpower, the tests will allow the municipality to make a cost-effective decision when the time comes.

Most of the wood collected for the test blocks will be passed through a chipper and brought to the sewage treatment plant to help create biosolids for municipal use.

If thinning projects go ahead, other potential users include a craftsman who makes therapeutic oils out of young pine needles, landscapers, and the municipality, which wants to use the wood chips to hold snow on cross-country ski trails. Some of the material may also be sent to the composting facility in Squamish, providing that it’s free of cedar.

So far there hasn’t been any negative public reaction to the thinning project, says Brett, who remembers the protests that erupted when a similar program was used in Stanley Park.

"I think most people are outdoorsy enough here that they can understand what we’re doing. We’re not logging to make money, we’re doing it to save the forest essentially, and improve the area for wildlife. People know second-growth when they see it, and when a forest is too dense.

"In two or three years, if we’re successful, we hope people won’t even be able to tell we were here."

Brett, Blackwell and forestry expert Francois Sauvé, who are running the experiment, have set up photo point areas that will allow them to monitor the progress of the thinned areas. It could take 10 to 15 years before they can make any conclusions, and even then the test area is too small for research purposes. However, they say they should be able to see a difference with wildlife and understory vegetation a lot sooner.

The project got underway on Monday, Oct. 25 and will continue until the first week of November. During this time a section of the Centennial Trail has been closed to the public.