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Beetle Taking Large Toll in British Columbia
Epidemic spread of destructive mountain Pine Beetle now claims 17% of province''s forest resources.
By Alan Froome
Date Posted: 11/1/2002
British Columbia used to proudly put ‘the evergreen playground’ on license plates. Lately, however, the forest has been turning an ugly red in many areas.
The change has been wrought by an infestation by the most destructive forest pest in Western Canada, the mountain pine beetle (MPB). By the time needles of coniferous trees turn red, the trees are already dead from beetle attack a year earlier. The insect mainly attacks mature lodgepole pine but also infests ponderosa pine.
Following several milder winters, the MPB infestation has reached epidemic proportions. According to government officials, 17% of British Columbia’s immense forest resource is now affected, not including the forests contained in national parks.
To put this into perspective, trees killed by the beetle would produce the equivalent of 17.8 billion board feet of lumber, enough to build 2.2 million average homes — more than the total built in a good year in the U.S.
This is an increase of as much as 80% over the area affected in the previous year. Most of the infestation is in the central portion of the province, but areas down to the U.S. border and further south also have been impacted.
The mountain pine beetle is just one of several beetles found in North American pine forests. Normally they exist in small numbers; their spread is naturally controlled by winter cold and forest fire. The insects, less than ¼-inch long, basically have a one-year life cycle, and understanding the timing of the life cycle is critical when dealing with infestation.
In June and July, after mating, the MPB flies to a tree, bores a tiny hole through the bark and lays eggs, and dies, also infecting the tree with a bacteria that causes a fungus to grow. The eggs hatch into larvae in August and September, and in the following two months they develop their own anti-freeze to help them survive winter. They hibernate under the bark until spring.
In April and May, the larvae come out of hibernation and feed on the fungus, which now causes a blue stain in the wood. Their activity under the bark cuts off the flow of water and nutrients, and the infested tree begins to die.
In July the insects emerge from the tree as mature beetles. They look for a mate and fly to a fresh tree to begin the cycle again. Some beetles will go to the nearest tree and others will fly up, dispersing in the wind to colonize a new area.
How is the forest industry in British Columbia dealing with the problem? The approved strategy is to try to minimize the spread of the beetle by "sanitation harvesting." Infested trees are removed by logging, especially while the bugs are still under the bark, in July and August. Tracts of dying trees are logged before the trees dry out completely. Traps are set to catch adult flying beetles. Logs are processed at mills as quickly as debarking kills most of the insects. Finally, the bark is burned for hog fuel.
The beetles have spread from huge provincial parks, where logging is banned and they have free rein. They can travel up to 20 miles in the wind outside park boundaries.
Eventually, natural forest fire will burn the dried-out dead trees, but they are unsightly in the meantime, and it takes many years for the forest to recover. Tweedsmuir Park in central British Columbia has been described as devastated; Manning Park in the south near Washington also is badly infested.
It is almost impossible to see the tiny holes bored by the beetles into the trees until pitch and wood dust appear at the surface. By that time, however, the tree is dying, and its needles are turning tell-tale red.
A company in Delta called Phero-Tech Inc. supplies traps and monitors them for MPB and other beetle activity in most of the affected British Columbia mills. Dr. J.H. Borden and other scientists from nearby Simon Fraser University have developed special traps and bait to catch the beetles. The bait combines tree resin with pheromones produced by both the female and male beetles to produce a sexual attractant. The bait is released gradually in a controlled manner.
The traps were developed by another Simon Fraser scientist, Dr. S. Lindgren, and have been in use since 1981; they resemble a series of stacked funnels with the bait suspended alongside. They have proven very successful in catching several types of pine beetles.
At the Weyerhaeuser mill in Princeton, a three hour drive east of Vancouver, timberlands manager Rob Marshall said the beetles attack only mature trees. Weyerhaeuser uses a helicopter regularly to check for new outbreaks. It logs affected trees while they are yellow — before they dry out and turn completely red. There is a small infestation in some ponderosa pines right by the mill entrance road, but the trees are on private property, and the owner does want to remove them. The last widespread infestation was in 1987, Rob noted, although the mill processes some logs every year from beetle kill. Weyerhaeuser installed Phero-Tech traps at various locations, including around the mill yard, and it processes infested logs as soon as they arrive at the yard.
Normal practice in most of interior British Columbia is to conduct logging in the winter, when the ground is frozen hard, and store the tree length logs — with the bark on — in the mill yard for processing throughout the rest of the year. However, infested trees should be debarked as quickly as possible and processed — not stored for long periods. In fact logging truck drivers in British Columbia have been instructed not to stop on the way to a mill — after beetles infested an area in the central province around a restaurant that is popular with drivers.
The current expansion factor in Rob’s area is as high as 20:1; in other words, the beetles will spread from one tree to infest 20 more. The normal expansion factor is 1:1.
Weyerhaeuser has had no problem selling a percentage of blue stain lumber to North American and European customers, according to Rob. However, other mills shipping to Japan have encountered resistance because Japanese customers are very conscious of appearance and will not accept any blue stain wood.
A small company near Quesnel called Eagle Eye Log Homes is actually marketing the blue stain wood. The company builds log homes in kit form using the logs from infested trees. It has been using beetle kill lodgepole pine logs as they are already dried out below 12% moisture content. As an option to customers, Eagle Eye purposely selects logs with blue stain, which it markets under the trademark of ‘Denim Pine.’
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