Mountain Pine beetles are killing millions of trees in BC's interior forests, but a forester recounts the forests' history and argues against "salvage" logging.
by Edo Nyland
The Prospectors Are Coming
When in 1840 the strike-anywhere match came onto the market, the new invention soon became standard equipment for the wave of prospectors that fanned out over BC and the Yukon, looking for mineral riches.
Most of British Columbia east of the coast range was covered in white spruce and interior Douglas fir, with lodgepole pine and some hardwoods scattered in between. The prospectors needed to see the rocks, so when the weather was right they burned the forest and the organic humus layer so severely that mineral soil was exposed. The new match was a wonderful and simple tool and was used frequently and everywhere. In short time, it would also aid in providing the much needed dry wood to keep warm in the winter.
But fires have a habit of growing and many millions of acres were burned needlessly, but who cared? The land was empty, except for, as the prospectors and miners put it, "some roaming Indians who had legs and could run away." The practice also gave the unexpected benefit of a much reduced mosquito problem and many areas were set on fire just for this purpose.
From the Cariboo gold rush on, most of the interior forests of BC were devastated. Pioneer tree species like lodgepole pine and aspen took advantage of the new opportunity and always recovered the ash-covered mineral soil, but organic soil needed centuries to recover. The pioneer trees were a blessing for our province because they covered the bare soil and prevented much erosion.
Burn Baby Burn
In 1896 the Yukon gold rush started and the permafrost had to be melted to get at the placer gold. Until the early 1950s, the Yukon Government issued official fire permits to set the forests along the Stewart and Yukon rivers on fire to supply the needed dry fuel wood for the many river boats and for the placer operations. The southern and central Yukon went up in flames, converting the predominantly spruce forests into pine forests. But only the smaller, easier to handle trees were utilized.
The new match had been an instrument of destruction for the forests of BC and the Yukon. The forest balance and its dependent animals, as had existed for centuries, was totally altered.
The lodgepole pines are fire-dependent trees and loaded with many different turpines which make up the turpentine and resins in the wood and the needles. Most cones on the trees are locked closed with a strong resin bond that needs to be broken by the heat of a fire, only then can they release their seeds. These trees are totally dependent on fire and burn they did, so fire followed fire followed fire, leaving nothing behind that could form the much needed organic layer, the home of the unseen forest.
The Unseen Support System
Every forest is supported by an unbelievably complex system of mycorrhizal fungi with thousands of interacting, living components and what we know about them is very limited. Hyphal threads of this fungal system grow into and around the feeder roots of the trees bringing them phosphorus and other nutrients from the forest soil. In these fungal-root connections, the exchange takes place between minerals from the soil and sugars which the tree produces in the needles by photosynthesis. This beneficial exchange is called mutualistic symbiosis and neither the tree nor the fungus can live without it. There is always plenty of this sugar produced and the surplus is passed on to feed all other workers in the underground support system.
When the soil is burned virtually all of this unseen and indispensable support system is killed and the organic humus layer is destroyed, but some of the tougher species may survive in the mineral soil below. Without the periodic flow of photosynthate the organisms have three choices:
- die,
- go dormant,
- become saprophytic (living on dead organic material).
Some fungi may be able to survive long enough for the new trees to start growing but in general the burned over area will need to be re-inoculated by spores drifting in from intact forests. Interconnecting the roots of all the trees, as was the case before the fire, may take as much as a century, a few species may take longer. Restoring the essential population of little helpers like mites, nematodes, springtails etc. may take even longer. When this support system has been restored, the time is right for the original forest to return, which happens to be now.
Nature Makes A Comeback
Nature is indomitable and wants to heal. In wet or protected places, clumps of spruce here and there had managed to survive the 150 year carnage and the wind distributed their millions of seeds far and wide. In time, almost everywhere the spruce trees came back as an under-story, growing in the partial shade of the pines and aspen trees, but they will do so only if the mycorrhizal support system has fully recovered.
The pioneer over-story, covering these enormous areas, is now up to 160 years old and becoming decadent, but they are now enormously valuable for the future health of the spruce forest. Over the decades their wood has stored masses of organic matter and nutrients, now desperately needed by the mycorrhiza and the developing crop of spruce and fir, growing up underneath.
So nature engaged the mountain pine beetle to convert the short-lived trees into something the mature white spruce and Interior Douglas fir could utilize. The beetles kill many or all of the pine trees, open up the tree canopy and set the long process in motion to turn the pine wood into a humus layer, thereby restoring normality to the forest. The support system, made up of an endless variety of little fungi and creatures, will make sure that the released nutrients reach the young trees.
There Is No Waste Involved In Leaving Pine Trees Standing
The beetle went to work, doing its assigned task, and in the process coloured the fast-aging pine forests a pretty red, ready for the stored-up nutrients to be made available and enriching the soil. No harm is being done anywhere, just nature doing its healing work. But some people see it differently and want to "salvage" the wood. If this is done by horse logging there is little harm, but using anything bigger may well be disastrous.
For one dollar's worth of profit, the machines may destroy one thousand dollars' worth of future benefit. Logging companies don't see those little trees as having commercial value. They don't, but they do have future value. Wake up BC. There is no waste involved in leaving the trees to die, just many benefits for the generations as yet unborn.
* Edo Nyland is the Retired Chief Forester of Yukon Territory
[From August/November 2001]