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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."