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B.C.'s drought: Forests at risk from drought, but climate change isn't the only culprit

Drought can also be exacerbated by land use, forest-management decisions and urbanization, says a forestry professor.
A Pat Bay Highway sign in June shows a low fire danger. DARREN STONE, TIMES COLONIST

This story is part of a series exploring the wide-ranging impacts of persistent drought conditions and climate change seen across the province in recent years.

Drought, human-caused changes to land and groundwater, disease, insects and fast-moving wildfires are some of the factors putting B.C.’s forests at risk this summer.

Wildfires are getting bigger, hotter and more frequent as a result of climate change, says ClimateReady B.C., a provincial government online portal providing information and services around climate and disaster risk.

Longer, hotter summers lead to more droughts and a longer wildfire season, it says, and dry conditions make it easier for lightning storms and strong winds to start fires.

Those fires, in turn, can spread, combine and burn for longer.

This year’s fire season is off to a slower start than last year’s, which set a new record for destruction with more than 2.84 million hectares burned — significantly up from the previous record of 1.35 million hectares burned in 2018, the province said in its 2023 wildfire summary.

Tens of thousands of people evacuated their homes and hundreds of houses and other buildings were lost or damaged in 2023.

This year, temperatures close to normal levels slowed snow melt and helped keep the lid on fires that smouldered through the winter, wildfire service lead forecaster Matt MacDonald said in mid-June.

Younes Alila, a professor in the Faculty of Forestry at the University of B.C., said snow plays an important role in replenishing groundwater. When snow melts over several months, it drips down through tree canopies to recharge groundwater, which comes in handy during dry weather, he said.

But during heavy rainfall caused by atmospheric rivers, snow can quickly melt and flow to the ocean without having the chance to seep into the ground.

Climate change isn’t the sole driver of drought, however; it can also be exacerbated by land use, forest-management decisions and urbanization, Alila said.

For example, when areas that have been clearcut are replanted, new young trees consume far more groundwater than the old forest.

Existing and historic logging roads also play a role. Subsurface water — built up mainly from snow slowly melting — is intercepted by the banks on the roads and converted into runoff.

What was once useful groundwater is funnelled into road ditches and then drained by culverts into gullies and streams heading into the ocean, Alila said.

Thomas Pypker, chair of the department of natural resource sciences at Thompson Rivers University, said that coming out of the winter with a “very low” snowpack is the biggest water concern. Although the province benefited from some spring rains, a lot more precipitation is needed, he said.

A change in the way we look at water is also important, Pypker said.

“Just because you see water around you doesn’t mean it’s plentiful enough that we can be wasteful,” he said. “I think there really needs to be a shift in our thinking about how we use water and treat it as something that’s extremely valuable.”

While efforts are underway to manage drought long-term, one problem is a lack of a good understanding of the hydrology in the province, said Pypker, noting only some areas of B.C. have meters tracking water use.

“How to you plan if you don’t know what you’re using?”

Pypker said it’s also important to look at the tree species being planted because some, such as lodgepole pine, burn more easily than others. Aspens, which are less prone to burn, could help create a firebreak.

Bill Beese, a retired Vancouver Island University professor and forest ecologist, said it’s clear on the Island that moisture-loving cedars, particularly western red cedars, are suffering under drought. Western hemlock and grand first are also at risk.

During a drought, the top of a tree can be the first to suffer. Tops may topple off or a tree will “flag,” where branches and foliage turn red and die and then drop off.

The impact of drought — which on the Island largely affects the area south of Campbell River — isn’t always immediately obvious.

A tree can look fine through the winter but won’t green up in the spring. “Basically it’s been dying all winter and you didn’t really notice it,” Beese said.

Drought will kill off the fine small roots used by the trees to draw much of their water, he said. These small roots go between soil particles to get water but when conditions dry up, they are the first to go.

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