Large tracts of forests within North America have been affected by recent bark beetle outbreaks. Millions of pine trees are turning red and dying throughout the western U.S. and British Columbia. The Ministry of Forests in British Columbia estimated that 7 million hectares of timberland pine forests have been affected and predict that 80% of British Columbia's pine forests will be killed in this beetle epidemic by 2013. While these figures can be daunting, many forest scientists stress that insect outbreaks are in line with the changing nature of forest ecosystems and historical norms. The beetle outbreaks have created challenges for forest managers who must incorporate ecological, economic and social issues into forest management plans.
The Bark Beetle Epidemic
Bark beetles have been a naturally occurring disturbance within forest ecosystems for thousands of years. Normally, bark beetles exist in small numbers and only kill weak trees. However, historical epidemics have occurred in which bark beetle populations increased to an amount where numerous healthy trees were killed on a large scale. Outbreaks often last several years and can even span decades.
Warmer winter temperatures and dense forests of mature trees are among the causes of the current epidemic in pine forests. Mild winters allow large numbers of beetle larvae to survive and consequently feed on trees, while trees competing for resources in dense forests become more vulnerable to beetle attacks. Beetle damage has been observed at, what is believed to be, higher elevations in Colorado than historically seen, which could hold new implications for future forest health. This observation, however, has yet to be rigorously investigated.
Distribution Map of Mountain Pine Beetle (an important species of bark beetle)
USDA, 1990
Extent of Bark Beetle Outbreaks in Western North America
Many outbreaks occur within this region's forests and are often caused by a variety of different beetles and insects. In Colorado, 660,000 acres of lodgepole pine forest were killed by the Mountain Pine Beetle in 2006. That is 44% of Colorado's 1.5 million acres of lodgepole pine forests. State foresters anticipate that more fir, spruce and aspen trees will replace these once dense Lodgepole stands.
In 2004, eastern Washington had 415,000 newly infected acres where Mountain Pine Beetle killed 4 million lodgepole and ponderosa pine trees. Western U.S. states also experiencing outbreaks of Mountain Pine Beetle and/or other insects include Arizona, New Mexico, Oregon, Wyoming, Idaho, Montana and California.
Harvesting as a Management Tool
In order to deal with the large quantities of valuable trees being killed, major Canadian timber companies have changed their harvesting plans to harvest only beetle-kill timber. New companies are also springing up to harvest the beetle-kill wood and market it as a local home-grown product. Major timber companies in the U.S. are harvesting beetle-kill timber to produce paneling, landscaping timbers, rails and posts. The beetle-kill wood, despite being a blue tint due to a fungus the beetles carry, is structurally sound and can be harvested up to a few years after death. One major concern, however, is if an excess of beetle-kill wood can find a place in an already saturated market.
It is also widely believed that harvesting the downed wood can be used as a management tool to prevent the spread of beetles and to decrease the probability of fire occurrence and intensity. These theories are still being debated within the forest science community. Forest ecology is an extensive subject and requires scientific rigor to explain its processes. There are numerous factors to be assessed when discussing treatment, prevention and overall management of forests in general, including those experiencing insect epidemics.
Reforestation
The timber industry is also participating in reforestation efforts on land affected by the outbreaks. In 2008, an estimated 4,000 hectares will be planted by British Columbia in the Williams Lake and Quesnel timber supply areas. Future planting of 8,000 hectares is currently being planned. Restoring forest resources is a key objective of the Mountain Pine Beetle Action Plan, British Columbia's plan to manage infected forests as a source of ecological and economic wealth.
RELATED LINKS
The Mountain Pine Beetle Epidemic and the Impact on Canada's Forest Products Industry
EARTHTRENDS
From Forests to Floorboards: Trends in Industrial Roundwood Production and Consumption
