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Monique Keiran: Climate change threatens Garry oaks

When I first moved here, one winter many years ago, a longtime area resident gifted me with a list of some of her favourite outdoor spaces.

When I first moved here, one winter many years ago, a longtime area resident gifted me with a list of some of her favourite outdoor spaces.

She rattled off the names of parks and trails that she enjoyed, then let slip the name of a small hilltop Saanich park.

“For spring wildflowers,” she said, adding, as if no explanation was needed: “It’s original Garry oak meadow.”

Then, with quiet satisfaction: “It’s small, it’s not well known and the parking sucks.”

So, the following April, I found my way there. The day was damp and blustery. Watery-looking sunlight filtered through evergreens towering along the path. I was not far into the woods when the sound of traffic from the busy roadway behind dropped off.

I climbed the hill and stepped out of the trees. Blue camas and buttercups swathed the ground. A few gnarly, naked oaks stood guard. Beyond some rocky outcrops, I discovered a patch of fawn lilies. A few satin flowers lingered on, while the first death camas of the year bloomed.

“So this is a Garry oak meadow.”

In the years since, the small farms that once bordered the park have given rise to single-family dwellings and townhouses instead of sheep and horses. Ivy, blackberry, Daphne laureola and other invasive plants choke the lower forested slopes, while other non-native plants have invaded the south-facing meadows.

But the greatest threat to this quiet, little jewel remains ill-defined and uncertain, as it does to special places everywhere. Scientists predict that, over the next decades, the seasons here will feature greater extremes. Hotter, longer, drier summers will anchor the year, with frequent, intense storms punctuating the other seasons.

How changing climate and its attendant baggage will affect Garry oaks and their attendant plants, microbes, insects and other critters remain unknown. Whether this Garry oak meadow will survive also remains uncertain.

Elsewhere in B.C., scientists, policy-makers and forestry professionals delve into similar questions. However, they spend their efforts determining changing climate’s effects on the province’s economically important tree species — lodgepole pine, Sitka spruce, and Douglas fir, for example — not geographically unique, timber-valueless species such as Garry oak.

We have, after all, seen how changing climate enabled a burgeoning epidemic of mountain pine beetles to kill mature pine forests across more than 14 million hectares of B.C. and economically devastate many Interior communities.

We can track changing climate’s links to the Douglas fir beetle outbreak in the Kootenay and eastern Chilcotin, and possibly to the current Dothistroma fungus epidemic in northwest B.C. Other climate-enabled insects and diseases are likely gnawing away at our forests and the B.C. forest industry’s future.

Determining climate change’s possible affects and what to do about them is complicated and controversial. In terms of B.C.’s forests, trees live a long time, and take many years to reproduce.

Although these same species have adapted to climate change many times in the past — since before the end of the last ice age — they’ve never faced a rate of change like that which is predicted over coming decades. According to computer models, tree species might be able to expand their ranges by as much as 130 metres each year if left to their own devices to deal with changing climate. Again, that’s too slow for the climate forecasts.

Ecosystems are already shifting northward, up mountain slopes and even eastward, but factors other than seasonality and temperature limit species’ abilities to become established and survive where future temperatures beckon.

Precipitation, soil quality, the presence of the required underground microbe communities and even individual trees’ own weaknesses restrict species’ abilities to expand or shift their ranges over time.

Some scientists advocate helping tree species migrate by planting them today in places where their optimal climatic conditions might eventually exist. However, because trees take decades to mature, any species that is planted in, say, 2015 must be equipped to survive local conditions not only in 2015 but also in 2035, 2055, 2085, and so on — whatever those local conditions might be in those future years.

I concede that work on pine, spruce and fir must continue, but can’t help wondering where I will find a pristine Garry oak meadow to marvel at in April 2055.

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