In 2015, more than 65 experts on the potential impacts from a spruce budworm outbreak were assembled into task teams by the SBW Task Force leaders to address the following key issues: wood supply and economic impacts; monitoring and protection; forest management; policy, regulation, and funding; wildlife habitat; public communications and outreach; and research priorities. Their recommendations are detailed in the final Task Force Report (including an initial risk assessment of the coming SBW outbreak) and summarized below.
Forest Areas at Greatest Risk
As tree defoliation by the SBW crosses Maine’s northern border from Quebec, all spruce-fir stands across the state are at some risk of defoliation. Spruce-fir stands dominated by balsam fir are at greatest risk as they can experience about 80% defoliation and are the most abundant tree by number in Maine. White spruce is the second most susceptible species to SBW in spruce-fir stands, but is far less abundant than balsam fir and generally experiences about 72% of the defoliation of balsam fir. Red and black spruce, which are quite common in spruce-fir stands, are also susceptible to damage by SBW.
Severity of Coming Outbreak
There is no way to predict exactly when defoliation of balsam fir and spruce will begin in Maine, how severe the outbreak will eventually become, or how long it will last. If the pattern of the 1970s–80s outbreak is any indication, once the next outbreak begins it is reasonable to assume that levels of tree defoliation will grow quickly during the first 5 years, reach a peak that lasts 5 to 10 years, and then decline rapidly over the next 5 to 10 years. A quantitative and subjective assessment of changes in 43 factors (including spruce-fir forest condition, wood supply, forest management, forest products manufacturing, logging industry, SBW monitoring capability, available protection measures) between today and when the last outbreak began in 1970 indicated more favorable circumstances in 55% of the factors, less favorable circumstances in 40% of the factors, and equal or unclear differences in 5% of the factors. Based on this analysis, the coming SBW outbreak will occur under very different circumstances than the last outbreak; as a result, the impact of and response to this outbreak will be different.
Projected Wood Supply Impacts
To date, there are 27.3 million cords of merchantable volume of balsam fir in Maine at risk of loss. For a severe outbreak, the projected total volume loss over the next 40 years (modeled with an outbreak start in 2013) is 12.7 million cords from a severe outbreak to 6.4 million cords for a moderate outbreak half of that intensity.
Projected Economic Impacts
Using the same models used to project volume loss, a severe outbreak without any forest management mitigation effort is projected to have a total economic impact of $794 million per year ($397 million per year for a moderate outbreak). Estimated annual job loss in the forest products sector would translate to 1,196 jobs and 598 jobs for severe and moderate outbreaks, respectively. Higher total job losses are also anticipated due to the multiplier effect of forest products job losses. The good news? It is possible to significantly reduce the spruce-fir wood volume and associated economic loss by adapting harvest activities, applying insecticide appropriately, and salvage logging of dead and dying trees.
Understanding the overall impact of the coming SBW outbreak on wildlife will depend largely on how species most closely associated with spruce-fir forest habitat will be influenced. Of special interest are those species (e.g., northern butterflies) and habitats (e.g., deer wintering areas, riparian zones) of special conservation value, as well as game species of economic and recreational importance. Mortality of mature spruce-fir, changes in harvest patterns, potential toxicity of insecticides, and increased forest fire risk are all major concerns for wildlife. From an ecological and wildlife perspective, forest changes will likely be positive for some species, negative for others, and neutral for yet others.
As the outbreak unfolds, it will be vital to periodically reassess and re-adapt response strategies that make biological and economic sense, as well as meet the overall needs of the State.