BC's baddest bug looks further down the forestry menu

The Pine Beetle, that nasty little critter that has laid waste to a large swath of pine forests in British Columbia, has apparently developed a taste for spruce and that has BC Forestry officials quite worried.

Researchers at the University of Northern British Columbia say that the beetle which until now was satisfied with a steady and unrelenting diet of pine trees has begun its march on the provinces' spruce stands.

Since it was first noticed back in 1993 the pine beetle has eaten its way through a huge tract of BC's pine forests from Prince George south to the US border, killing an estimated 530 million cubic metres of lodgepole pine and sending the BC Forest industry into a near crisis situation in some communities.

The disturbing revelation that the beetle is now targeting the spruce forests will be cause for concern, as pine and spruce are the one and two products in BC's forest industry.

Mark Hume of the Globe and Mail explained the development quite well with this piece from the Globe website today.

Pine beetle developing a taste for spruce
MARK HUME
From Thursday's Globe and Mail
June 27, 2007 at 7:35 PM EDT

VANCOUVER — The small beetle that has already eaten its way through about nine million hectares of pine forest in British Columbia with devastating environmental and economic impact is developing new appetites.

Researchers at the University of Northern B.C. in Prince George say the pine beetle, which since 1993 has unleashed an unprecedented natural disaster destroying about 40 per cent of the province's lodgepole pine, is now killing spruce trees as well.

“There were rumours before that pine beetles were not only killing spruce but successfully reproducing in spruce, and we have now observed that in Prince George and we have been trying to document what's going on,” Staffan Lindgren, a professor of ecosystem science at UNBC, said Wednesday.

Dr. Lindgren said that while the pine beetle appears to be branching out, creating even more of a threat to B.C.'s beleaguered forests, it doesn't point to an ecological disaster on the scale of the current attack. If adaptation does occur, as it appears to be, it will happen slowly and the new beetles initially would likely attack only weak spruce trees.

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“I don't foresee any risk to the spruce forest that would be immediate. But that's not to say that we couldn't see something in the long term that potentially could do [what the pine beetle has done],” Dr. Lindgren said.

He said the pine beetle appears to be involved in a “speciation event,” in which a new type of beetle is evolving.

“Over a long period of time, if we get a speciation event, we essentially get a mountain pine beetle biotype, or new species, that focuses on spruce,” he said.

Pine beetles have long been known to attack spruce trees, but the chemical composition of spruce – which contains the main volatile ingredient used in turpentine – has been able to kill off the invading insects.

Dr. Lindgren said pine beetles now appear to be developing a resistance to the harsh chemical environment in spruce and are able to breed and multiply to such numbers that they can kill the trees.

Researchers don't yet know whether pine beetles have killed any healthy spruce trees, or whether all the victims have been dead or dying. This summer investigators are “baiting” some healthy trees to attract beetles so they can monitor the results.

Since 1993, the pine beetle has killed an estimated 530 million cubic metres of merchantable lodgepole pine in B.C., turning vast swaths of forest red from north of Prince George to the U.S. border in the south.

While lodgepole pine is the predominant tree species in B.C., with enough to cover a forest area of about 14 million hectares, the spruce forest is second, accounting for about 13 million hectares.

Dr. Lindgren said UNBC researchers first became aware some pine beetles were shifting to spruce last summer when it was noticed that spruce trees were dying along with pines around the city.

Dr. Lindgren thinks the phenomenon is occurring because of the massive numbers of pine beetles in B.C.'s forests.

“It's possible that huge outbreaks like the one that we're experiencing now may provide the conditions by which speciation can occur in insects like this,” he said.

In any given pine beetle population there are bound to be a few insects that are better adapted to dealing with spruce trees. Because of the pine beetle epidemic there are now enough of those beetles that they are able to start breeding.

“There have been studies that suggest we've had these kind of host switching events in the past,” Dr. Lindgren said.

He gave as an example a subspecies of pine beetle that is believed to have evolved from spruce beetles. That insect feeds only on stumps or downed lodgepole pine.