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Whistler history lives in the core

Tree ring study to yield insight into Whistler wild fire history, insect infestations, and more Study by study, the natural history of Whistler is being pieced together.

Tree ring study to yield insight into Whistler wild fire history, insect infestations, and more

Study by study, the natural history of Whistler is being pieced together.

Fishing buffs have combed through pictures of early fishing trips to find out what the original fish species were before stocking programs began. Birders are counting the variety of birds living in and migrating through the valley. Experts in hydrology and fish biology are attempting to restore the natural flow of creeks that have been disrupted by human activity, from logging, to mining, to resort development.

Local biologist Bob Brett started a different kind of investigation into Whistler’s natural history this past August, examining core samples from trees in order to determine what role wild fires and other natural disturbances have had on our local ecology.

With the backcountry closed due to the fire hazard and the driest summer on record on the coast, Brett says it’s a good time to look at the fire history of the area to determine what a fire might look like, how to deal with it, and, more importantly, how it may be prevented.

The RMOW agreed, and gave Brett some funding for a pilot study on Whistler’s fire history.

"One of the things I’m finding on both sides of the valley are a lot of bigger trees that are 200 or more likely 300-plus years. There are some conclusions we might be able to draw from that, if I find the same thing everywhere I go," said Brett. "It’s still too early to tell what that means exactly, but it’s definitely of interest."

If trees are the same age, it’s possible that there was a large fire in the area around 300 years ago that ranged from one end of the valley to the other and consumed most of the trees. If there wasn’t a major fire or natural disturbance, such as a flood, insect infestation or disease, then trees should vary in age.

The only forest fires on record in the area were small, and date back to the 1920s and ’30s. The railroad was the main cause of fires, although some were attributed to forestry and mining operations.

According to Brett, the forests in Whistler are different than the forests of the Interior, where this summer’s wildfires destroyed more than 300 homes and several businesses, and will likely cost the province more than half a billion dollars.

Fires are a regular part of the natural cycle in the Interior, says Brett, with pine needles and dry grasses providing easy fuel for fires that burn out relatively quickly, only scarring the trees. As a result, trees are generally more spaced out and separated by grass.

"Fire suppression has allowed people to feel safe building their houses in these beautiful ponderosa pine forests, but the irony is that suppression leads to an inevitable result. When the inevitable fire happens, it becomes an unstoppable conflagration rather than a quick surface fire," said Brett.

Whistler, like other coastal areas, may not have fires every two to 20 years like some forests in the Interior, but they may still be a regular part of the local forest system.

After this summer’s blazes, fire suppression techniques are likely going to be used to thin out forests around homes in the Interior.

"Should we import solutions from the Interior to here?" asks Brett. "That’s the sixty-four dollar question."

By looking for evidence of fires locally, and getting an idea of what burned and what was left behind, Brett says we can be better prepared for the future.

"We lost a lot of evidence because of logging and development, but we can still come off with strong ideas how best to deal with it when it happens," he said. "What kind of wild fire management do we need, and what kinds of fires can we expect?

"It’s important to establish how important fire was (before Whistler was developed) in shaping our forests, since that gives us an idea of current risks."

As well as information on forest fires, Brett is also looking at core samples under the microscope for evidence of flooding, mountain pine beetle infestations, tree diseases, and more. He has currently taken samples from about 200 trees, and hopes to have looked at another 200 samples by the time he presents his initial report in December.

A group of 10 UBC students spent two days with Brett in September to collect core samples, which are being studied at the university as part of the students’ course work.

Brett is also taking stump disks from around the Whistler area to help him get a more accurate measure of the age of trees, and the years in which natural events occurred.

Although the study is far from complete, Brett has made a handful of interesting discoveries in Whistler. The first was a cottonwood tree that was more than 271 years old. One-hundred-and-twenty years is considered old for this species.

Another interesting find are some yellow cedars in the Lost Lake area that are more than 600 years old. Other trees were found on Blackcomb that were of a similar age.

Brett was also amazed by how fast spruce and cedar trees grow in Whistler’s valley bottom, maturing in between 60 and 80 years. As a result, some of the trees in the valley bottom are not as old as people believe, which points to the possibility of another natural disturbance.

Brett hopes to have a preliminary study available in December, and hopes to engage the public on the issue.

The first reason is to let people know that the municipality is taking steps to assess the local fire history and fire risk.

The second reason is to get the public involved, keeping their eyes open for really old trees, and trees with noticeable fire scars.

To make the pilot study more accessible to the public for a future presentation on the core sampling project, Brett is sampling some trees that locals would be able to recognize by sight, such as the large spruce tree at the bottom of Lorimer, the cedars just off the Valley Trail at the ninth hole of the Whistler Golf Course, and trees up Whistler and Blackcomb mountains.

Samples have been taken at plots from one end of town to the other, from the sub-alpine to the valley bottom. The goal, according to Brett, was to take representative samples from different altitudes and areas to determine if some areas of Whistler are more prone to fire than others.

The results will be used in the Whistler Wildfire Management Plan, the Protected Areas Network strategy, terrestrial ecosystem mapping, and more.