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Forest denizens struggle in clearings

External Reference/Copyright
Issue date: 
December 3, 2011
Publisher Name: 
Vancouver Sun
Larry Pynn
Author e-Mail: 
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Salvage logging of B.C.'s Interior lodgepole pine forests is having major consequences for wildlife by eliminating vast stretches of habitat used for activities such as feeding, hiding and keeping warm or cool.

While species such as the moose - a "generalist" that eats various types of plants - may benefit from the flush of new forage that follows clear-cutting, the outcome can be radically different for a host of smaller forest-dwelling plants and animals, including those that rely on tree species such as fir, spruce and aspen intermixed with the pine.

The province's chief forester has recognized the importance of leaving wildlife patches within clear-cuts, recommending salvage loggers retain at least 10 per cent of the forest in cutblocks of up to 250 hectares and 25 per cent in cutblocks totalling 1,000 hectares (2.5 times the size of Stanley Park) or larger.

The problem is, the province hasn't done the work necessary to determine the effectiveness of such patches.

Doug Janz, former head of wildlife for Vancouver Island with the Ministry of Environment and now chair of the forestry committee for the B.C. Wildlife Federation, criticized the province for not conducting baseline work in the beginning to determine the effect of large-scale logging on wildlife.

"We're missing out on a great opportunity," he said.

Janz added there is "no stable" program in place for the monitoring and inventory of wildlife across the province due to funding restrictions.

"I don't see any commitment to monitoring responses of species, habitat, water quality, peak flows - all these other concerns that have been identified with the massive clear-cuts."

Ultimately, what may be enough habitat for one species may be inadequate for another.

Phil Burton, a forests researcher with the Canadian Wildlife Service, confirms that the question of "how much is enough" is a problem that plagues conservation science.

"The threshold differs for almost every species. It's hard to come up with one size that fits all."

A Canadian Forest Service report, largely a synthesis of environmental research to date on the salvage logging of pine forests, noted there are wildlife patches left in large clearcuts that are not sustainable for vascular plants such as mosses and liverworts.

"The retention patches were too small to prevent loss of species over time," the 2011 report found.

Salvage logging can also affect threatened caribou, which have been found to forage in dead pine forests where the snow is softer and easier to dig. One study showed that caribou foraged exclusively in beetleinfested pine forests when snow depth exceeded 50 centimetres. Observed effects vary according to individual herds.

Grizzlies may benefit in the first decade after pine beetle salvage logging, then suffer reduced food supply as the new forest thickens and closes in. A side-effect is the fact that logging roads increase human access into the backcountry and the potential for fatal conflicts with grizzlies.

A report for Tolko Industries Ltd., found the red-backed vole, yellowpine chipmunk, red squirrel and snowshoe hare prefer forest habitat over clear-cuts.

And that poses problems for their predators: marten and fisher (a species of special concern). The report said the "presence of forested reserves in clearcut areas is likely to be essential" for eventual recolonization of harvested areas.

Deer mice, however, which are also potential prey for marten and fisher, were more abundant in clear-cuts.

Kathy Martin, a researcher for both Environment Canada and the University of B.C. forestry faculty, found that woodpeckers fared better when aspen and large Douglas fir were left behind during the logging of pine forests, a finding that reinforces the ecological importance of retaining a mixture of tree species.

"In the beetle case, it's boom and bust," Martin said. "No [specific bird species] has been lost, but it has destabilized the populations for a number of years."

A study by researcher Ann ChanMcLeod, published in the BC Journal of Ecosystems and Management, looked at the wildlife values in a beetle-killed pine forest and the implications of salvage logging.

Species such as brown creeper, redbreasted nuthatch, northern flicker and various woodpeckers feed on the pine beetles during the initial attack.

As pine needles fall off the trees, they are consumed by snowshoe hares, as well as by blue and spruce grouse.

The loss of forest cover has serious consequences for a range of bird and mammalian species, affecting the search for food and mates, the chances of juveniles dispersing to new territories and the migration of species between seasonal habitats.

The effect on animals - such as the pine grosbeak, Hammond's flycatcher and woodland caribou - that rely on mature forests can be particularly harsh. Prey can disappear. Lynx, for example, feed primarily on snowshoe hare, which inhabit forested areas with dense conifer thickets.

The loss of forest cover also affects the ability of species such as moose, elk, caribou, mule and white-tailed deer to hide and keep warm in winter or cool in summer.

Research also shows that salvage logging increases the magnitude and frequency of floods in spring, while warmer waters downstream of salvaged sites pose a threat to fish such as bull trout, a species of concern.

The flood risk diminishes only as a new crop of trees grows in the clearcut land.


The aftermath

A five-part series on the lingering effect of the mountain pine beetle infestation and the strategies used to fight the pest and salvage as much wood as possible.

Friday: Pine beetles, salvage logging and the environment

TODAY: Inside a 'dead' forest

Monday: Flooding and the effect on ranchers

Tuesday: The bite of salvage logging on ecotourism

Wednesday: The struggling forest industry


Extpub | by Dr. Radut