North Idaho's forests are at risk
Opinion Editorial
In the past decade or so, we have seen an increase in the number of outbreaks of forest insects and diseases in our western forests. Since the mid-1980s we have seen simultaneous outbreaks of five different bark beetles and the Douglas-fir tussock moth has defoliated 400,000 acres of trees. Root disease is everywhere in the forests of North Idaho.
While native insects such as bark beetles are a normal part of the environment and serve as agents of change in the ecosystem, the intensity and frequency of the outbreaks reflect that our forests are out of balance. Outbreaks have occurred in the past, and some of them have been very large; however, they have not occurred on such a frequent and concurrent scale. The real problem is not the insects and diseases, instead it is the condition of the forests that is stimulating the outbreaks. The magnitude of the current Douglas-fir beetle is a reflection of how North Idaho forests have changed over the last 100 years from pines and larch to Douglas-fir and grand fir.
Exotic insects and diseases area also causing significant changes in our forests, again indicating conditions that are out of balance. The incidence of blister rust in western white pine is a prime example of a worst-case scenario. The percentage of western white pine left in our North Idaho forests is dramatically less than it was historically, due largely to the impact of this disease. A non-native insect called the balsam woolly adelgid is also decimating subalpine fir. It has killed virtually every tree in many cool-air drainage bottoms and is now making its impact felt at higher elevations.
Are these forests sustainable in their current condition? The answer is no. There will always be trees growing in our forests. However, they will not be the same species that were here prior to European settlement or that grew in the forests just 50 years ago. These forests will be ecologically sustainable on a long term basis, that is trees will live and die, recycling nutrients to the soil, providing habitat for animals, etc. However, in the short term, the increasing numbers of shade tolerant species like Douglas-fir, grand fir and hemlock are significantly changing the composition and structure of our forests putting them at increased risk to catastrophic wildfire, insects, and diseases.
Will these forests be able to provide for the needs of people over time? They are becoming less and less able to do so. The increasing mortality from insects, diseases and fire are causing a major impact on the resources available for our use.
What are the alternatives? Modern forest management can be used to increase the vigor of our forests, making them resistant to insects and diseases and less likely to be lost to wildfire. We can decrease the amount of Douglas-fir and grand fir and replace them with pines and larch. We can replant the lost western white pine with seedlings that are resistant to blister rust. We can thin stands that are too dense.
We do not have to stand aside and watch our forest resources die unnecessarily. With action, we can have healthy forests that are sustainable both ecologically and in providing for our needs for generations.
R. Ladd Livingston, Ph.D.
Forest Entomologist
Supervisor, Insect and Disease Section
Idaho Department of Lands
Coeur d'Alene
