There is 20 times more carbon in a mature Kootenay forest than in a five-year-old clear-cut in the same area.
This is one of the conclusions following research carried out this spring by four students of forestry professor Dr. Suzanne Simard in an area known as the Argenta-Johnsons Landing Face in the Purcell Mountains on the east shore of Kootenay Lake north of Nelson.
Their study also described how the level and type of plant diversity differs greatly between the forest and the clear-cut.
The students’ work is noteworthy for several reasons.
Their results confirmed recent research from around the world showing that when a forest is clear-cut it becomes a net emitter of carbon, rather than a storehouse of it. This research at the Argenta-Johnsons Landing Face was unique, however, because this had never been assessed in the region or in this particular forest type.
Simard is also well-known for her groundbreaking research into forest fungal networks, documented in her book Finding the Mother Tree: Discovering the Wisdom of the Forest, that is soon to be made into a feature film.
The researchers set up six plots, three in the clear-cut and three in an approved cut-block about to be logged. They used a standard measurement tool known as the National Forest Inventory Protocol to inventory all the carbon stocks and all of the biodiversity in the plant community. They also took note of any wildlife species that they observed.
Simard says she chose this forest to study because it was a place of special interest. It is uniquely located between Kootenay Lake and the Purcell Wilderness Conservancy Provincial Park, and “it’s culturally really important … it’s controversial, and we want to know more information about it.”
Simard said the results are consistent with many studies across the globe that have found that the world’s major forests, including Canada’s, have shifted since the mid-2000s from storing carbon to emitting it.
“Because of logging, because of wildfire, because of the insect infestations, which are all linked together, they all amplify climate change,” Simard says.
How is the carbon from logs transformed into carbon dioxide in the atmosphere?
About 65 per cent of it is turned into toilet paper, short-term cardboard or other short-lived products that end up in the waste stream almost immediately, to decompose and release CO2, Simard says. About 35 per cent ends up in longer-term products like lumber or furniture that will last on average about 25 years.
Simard says there was also carbon lost from the soil in the clear-cut, but the results of the soil samples are still being analyzed. Other research by Simard has found that about 60 per cent of forest floor carbon is lost when conventional logging is used.
She says it’s because of the machinery.
“It gets pushed around by the big machines, gets pushed into piles, some of it decomposes, some of it burns in a burn pile. Basically it’s the machinery that is having a negative effect, like the big skidders.”
This woody debris, she says, is acceptable if the pieces are big enough, because they contribute to carbon storage. But small woody debris and finer particles are highly flammable and will release large amounts of CO2 if they burn.
Simard calls the forest at the Argenta-Johnsons Landing Face a transition between a dry and wet forest, and as such it is very rich in both plant and animal species.
“It’s a hot-spot for biodiversity.”
She said her students found a large shift in the plant community between the forest and the clear-cut.
In the students’ analysis, only 11 understorey species were common to the forest and clear-cut. Twenty-one species were unique to the clear-cut, and 22 species were unique to the forest.
In the clear-cut they found what she calls weedy species, such as fireweed, that tend to invade open areas. In the clear-cut there was also a loss of lichens and mosses.
Simard said the work of her students shows a need to re-think clear-cutting. Studies have shown forest practices contribute up to 20 per cent of greenhouse gases worldwide, she added.
Carbon is being stored in trees, plants, debris and soils, and we are losing most of that with clear-cutting, she says.
“We’re doing that all across our country, and we’re doing it all across the world. People who are well informed about the current climate of climate change and biodiversity loss are saying, no, the rules of the day are changing quickly, and we don’t want this anymore.”