Researchers take hi-tech approach to ensure timber supply is firm
by Paul Harris*

The creation of an innovative "mosaic" pattern of trees varying by both species and maturity is viewed as a key future strategy to ensure forests in British Columbia are best-equipped to repel an insect attacking mature lodgepole pine.

This method of replanting is part of a wider attempt by researchers examining the infestation of mountain pine beetle on forestland in the southern and central Interior of B.C. Hi-tech analysis such as digital aerial mapping is being used to help experts identify future beetle hot-spots, where direct action such as silviculture and earlier pine harvesting can help stop the beetle in its tracks.

Species such as Douglas-Fir, spruce, hemlock, cedar and true firs are not affected by the infestation. While lodgepole makes up a small proportion of the overall volume of timber shipped from B.C. to Japan, industry and government in B.C. are analysing harvesting timetables to mitigate the affect of pine removal on other species.

With wood-frame construction enjoying a solid presence in Japan, additional work is underway to discover new uses for lodgepole pine infested by the beetle, such as environmentally-efficient energy production and in growing engineered wood product market.

The beetle is by no means a new problem faced by harvesters. In fact, the beetle - which is the size of a grain of rice - is indigenous to parts of Canada, the USA and Mexico. Beetles play an important role in the natural life cycle of lodgepole pine forests by attacking older or weakened trees that are then replaced by new healthy pine forests. But due to the sheer volume of mature lodgepole pine - the dish of choice for the beetle - the size of the infestation has grown considerably in recent years in the southern and central Interior regions.

The area of mature pine forest in B.C. increased significantly from 2.5 million hectares in 1910 to over 8 million hectares by 1990. This large increase in the number of available trees correlates with the size of the current outbreak, with 108 million cubic metres of timber affected in B.C. by pine beetle by the end of 2002.

Wood from beetle-attacked trees remains of merchantable quality for up to 15 years - offering harvesters a key opportunity to mitigate the losses expected from the infestation. B.C.'s Chief Forester, Larry Pedersen, said: "Mountain pine beetle damaged timber is very suitable for dimension lumber. It does not lose its structural attributes for the first 15 years. We will still be producing high levels of high quality solid wood products." This includes blue-stained lodgepole pine too.

Scientists believe the current outbreak was caused by a combination of a large volume of maturing lodgepole pine and the relatively warm weather conditions of recent years. Fire control measures undertaken to protect the forest resource, infrastructure and private property contributed to an accumulation of old pine forest that far exceeded historical levels. Once pine is mature, it is far more susceptible to the beetle, particularly during times of prolonged favourable weather conditions.

Forestry experts have also backed a temporarily rise in the volume of lodgepole pine harvested in British Columbia to offset the beetle epidemic. A temporary uplift in the annual allowable cut has been sanctioned, in order to harvest quickly the pine affected timber. Temporarily increasing levels will both aid the removal of green trees unharmed by the beetle, and aid the removal of beetle-damaged trees quickly to preserve the world-class qualities of the wood, said Mr. Pedersen.

In October 2002, a five-year, $40 million initiative began to respond to the beetle outbreak, led by both the federal and provincial governments. These strategies have been successful in reducing the spread of the infestation and limiting the amount of beetle-killed timber in some areas. Further research is taking place to identify options to mitigate its impact, and to cut the risk of future infestations in B.C.

Crucially, as with all harvesting, the province is committed to ensuring all actions coincide with its commitment to sustainable and environmental forest management. Indeed, Mr. Pedersen added, "The more we can direct harvesting at salvaging beetle-affected timber, the more green forest we can retain in the mid-term."

B.C. exporters are fully aware of the need to balance pine supply with demand in Japan and other Far Eastern markets. Dr. Les Safranyik, one of Canada's foremost authorities on pine beetle, said: "In the long term, the focus of management should be lodgepole pine, not the mountain pine beetle." He said that, in the past, large scale outbreaks have collapsed due to the localized depletion of suitable host trees in combination with adverse weather conditions. A sustained dose of extremely cold temperatures would delight researchers and help wipe out the beetle.

The impact of the infestation could be mitigated further if harvesting is directed towards the more severely infested stands, or if harvesting focuses more on pine, or if the forests regenerate more quickly than is currently assumed. Researchers agree that after harvesting, forests can regenerate within just 1 to 3 years - rather than the usual 20 years it takes to regenerate affected forests that are not harvested.

Predicting life after the beetles is key.

Dr. Terry Shore, a research scientist with the Canadian Forest Service based at the Pacific Forestry Centre in Victoria, said: "There are still parts of the province where the beetle is not quite at that high level so there are still some opportunities to tackle the beetle through direct control - harvesting and single tree treatments."

Further analysis is taking place throughout the province, such as in Quesnel and Prince George, to examine for example the effects of weather on the dispersal of the beetle. Dr. Shore said they have been examining ways to improve the vigour of existing stands, alongside direct controls such as harvesting, debarking and felling and burning. A key part of his work has been creating an effective ratings system for forests - a kind of sliding scale to ascertain the likely most susceptible forests, in order to reduce potential beetle habitat and tackle future trouble spots before the beetle population reaches epidemic levels.

Over the longer term, scientists agree that it will be crucial to find innovative ways to manage large areas of even-aged lodgepole pine forest. Future replanting will need to create a "mosaic landscape" of different tree species, and different tree ages, to reduce the chances of beetles being able to spread across large areas. Silviculture, although at an early phase as a "beetle solution", will likely have an important role, said Dr. Shore. He said reducing stand density, through thinning and spacing, could increase the vigour of remaining trees and make them more likely to withstand beetle attack.

Outbreaks of beetle infestation in North America are not uncommon. Beetles have been found in large numbers in several parts of the United States and northern Mexico, plus other Canadian provinces such as neighbouring Alberta. Ken Gibson, of the USDA Forest Service, confirmed that pine beetle has been found in large numbers in forests in several western U.S. states too.

ENDS

*The author is an independent forestry writer based in Vancouver, Canada