Pine beetle plague raise B.C. flood risk: expert
Pastor Dale Morgan
Pine beetle plague raise B.C. flood risk: expert*
Canadian Press
VANCOUVER BC CANADA -- A forestry expert says the B.C. government needs
to take "urgent" action to prevent flooding in some watersheds ravaged
by the mountain pine beetle plague.
Younes Alila, a forestry professor at the University of B.C., said
Monday that flat-terrained watersheds that are covered mostly by pine
and are clearcut to remove millions of dead trees are most at risk to
cause flooding.
He said the issue should raise alarm bells.
"Therefore this calls for the authorities within British Columbia to
order detailed investigations of the potential for flooding of the
Fraser River that may be related to the beetle," Alila told reporters in
a conference call.
"That is somewhat urgent because the decision on how much we salvage
logs could be a deciding factor on the potential for flooding in the
Fraser River."
Alila was basing his comments on a study he conducted for the Forest
Practices Board, an independent watchdog for sound forest practices.
An infestation of the mountain pine beetle has ravaged B.C. forests and
covers about 8.5 million hectares, an area more than twice as large as
Vancouver Island.
It's estimated that by the time the infestation runs its course in 2013,
80 per cent of the B.C. Interior's pine will be dead.
"The beetle is affecting a very large area of British Columbia," Alila said.
"We think, out of this piece of work, that the most heavily affected
area in terms of increase of flood risk would be the upper Fraser
(River) area, the Nechako area, and the Fraser plateau areas."
Alila used the Baker Creek watershed, west of Quesnel, for his research
because it has similar characteristics to those that are most at risk
for flooding.
He said his work shows the pine-beetle epidemic could increase stream
flow by 60 per cent in Baker Creek.
When clearcut salvage logging of the beetle-infested trees is added, the
stream flow could increase to 92 per cent, Alila said.
That's because melting snow is no longer intercepted by trees that once
stood in the forest. And trees that lie dead on the forest floor after
they've been killed by pine beetles don't hold the same amount of water
compared to when they were alive.
The result is a greater water flow into streams and a higher risk of
flooding.
Alila said his research shows floods that used to occur every 20 years
are now likely every three to five years.
Studies done in Colorado suggest it could take up to 60 years to
replenish conditions in watersheds, increasing the potential of flooding
even more, he said.
Bruce Fraser, chairman of the Forest Practices Board, said watershed
assessments that would help develop strategies to protect drinking
water, preserve fish habitats and prevent flooding are no longer
required under provincial legislation.
"We see (assessments) as being a highly prudent thing to include in the
professional assessment of watershed risks," Fraser said.
In the past, bridges and culverts were built on the basis of assumed
flood risks, he said.
Forests Minister Rich Coleman said the government requires forestry
companies to put watershed assessments into their forest plans.
"When they're working in a watershed they're supposed to do a watershed
assessment with a hydrologist and determine how best to cut and not
affect the watershed," Coleman said.
But Rob Duncan, spokesman for the B.C. branch of the Sierra Club, said
assessments in beetle-attacked areas are only voluntary.
"It's not a mandatory requirement but it's a good suggestion that should
be legislated."
Steve Chatwin, another spokesman for the Forest Practices Board, said
the study is not suggesting that clearcutting to deal with the pine
beetle should be curtailed because dead trees would pose a forest-fire
hazard.
"What it is is a heads up to all of the professional community about the
fact that the decisions they make with respect to salvage logging and
replanting have to be balanced against the decisions they make to
conserve the watershed hydrology," Chatwin said.