The Incomappleux

New Conservancy Protects Rare Ecosystem

Walking among the giant cedar, hemlock, and head-high Devil’s club of the Incomappleux River valley south of Glacier National Park, it’s easy to forget that the Pacific Ocean is 500km westward.

The Incomappleux belongs to a unique forest spanning a moist wet belt that’s nourished year round by deep winter snowpacks in the Columbia and Rocky Mountains. Measuring 15,000 sq km in size, it’s known as the Inland Temperate Rainforest, and the newly established Incomappleux Conservancy protects 580 sq kms of it.

This is an important and hard-won conservation victory. Craig Pettitt, a founding director of the Valhalla Wilderness Society, is one of the conservationists who for more than a decade has been championing the protection of the Incomappleux and other remnant patches of inland rainforest like one at the north end of Duncan Lake. If it wasn’t for a blown-out logging road too expensive to repair and a remote location, the timber rights holder Interfor would have already harvested the forests of the upper Incomappleux.

How coastal rainforests have flourished for thousands of years so far from the BC coast results from an interplay of topography, latitude and climate interior that is found in few other places in the world. That’s why for mountain folks like us, the Incomappleux and other forests like it are particularly fascinating. Precipitation in the Incomappleux falls below the threshold of annual precipitation that defines a rainforest, roughly 1400mm per year. However, winter is the difference maker.  Weather systems, laden with Pacific moisture, collide with the interior mountain ranges and delivers a deep snowpack that compensates for the moisture deficit. This creates localized conditions that mimic a rainforest, especially at the foot of mountain slopes where moisture seeps year-round. Such forests have historically been spared from massive fire events, fostering rich biodiversity centuries in the making and allowing trees to live to a thousand years or more. In terms of species mix, biodiversity, climate, and feel, these forests are more Walbran Valley on Vancouver Island’s West Coast than the interior mountain ranges where pockets of this ecosystem thrive. So big deal, why protect them?  Well, such forests can generate tourism – people will travel to visit big trees. Tall tree tourism has become a thing in Port Renfrew thanks to the Avatar Grove.

But more importantly is that biodiversity is key for planetary health, and the Inland Temperate Rainforest is a richly biodiverse frontier of scientific discovery. In the early 2000s University of Alberta botanist Toby Spribille studied lichens in the upper Incomappleux River valley and catalogued more than 280 species, nine of them new to science. A survey of mushrooms in the Incomappleux identified 50 species, half of which are normally found only in coastal forests.

Dwayne Coxson, a University of Northern BC lichenologist, and botanists Trevor Goward and Curtis Bjork, both affiliated with UBC’s Beatty Biodiversity Museum, have been studying the interior rainforests of the Robson Valley, roughly between the communities of Dome Creek and Upper Fraser on the Yellowhead Highway. In an area that includes both Ancient Forest/ Chun T’oh Whudujut Provincial Park and the 50,000-hectare Sugar Bowl-Grizzly Den Protected Area, the team has catalogued more than 2,400 plant species, including dozens of new discoveries. What’s even more surprising is that not all of them are “mosses and lichens,” says Coxson. “Some of them are vascular plants [a broad group of plants with tissues for conducting water and minerals – like fir trees or wildflowers.] It shows just how little we know about this ecosystem,” says Coxson. “Globally it’s a very unique ecosystem.”

Similar temperate rainforests are found this far inland in only in two other places, southern Siberia and Russia’s far east. According to Coxson, though scientific understanding of these rainforests has advanced, precautionary land use decisions in BC have not kept pace.

This forest once covered more than 160,000 square kilometres and stretched 1100km from central Idaho through BC’s mountainous interior as far north Prince George. According to some estimates, more than a quarter of this rainforest has been clear-cut logged and less than 10% has been protected.

That’s why the Incomappleux Conservancy, which came about after Interfor gave up 750 sq km of its forest tenure in the area, is worth celebrating. The Nature Conservancy of Canada brokered the deal, which includes support and funding from Teck Resources, several foundations, the federal government and individual donors. It also required the participation of First Nations in whose territory the valley lies. In reality, few of us will ever see the Incomappleux Valley. But that’s okay; knowing that this treasure exists is reward enough. 

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