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Insects & Pathogens

Forest insect and disease pathogens cause significant tree mortality, growth loss, and damage to large volumes of potential wood products each year and can alter habitats for birds and animals. They reduce management options for landowners and can contribute to hazardous forest fire conditions. However, these disturbance agents are also a natural and necessary part of forest ecosystems. They support ecological processes such as decomposition and nutrient cycling. They create canopy openings, enhance tree species diversity, and provide food and habitat that many animals depend on. A healthy forest is not free of insects, diseases, disturbances, and tree defects.

The Western Wildland Environmental Threat Assessment Center is concerned with the effects (adverse and positive) of native insects and diseases acting alone, together, or in concert with other agents of disturbance (i.e., fire, climate change, invasive species) on wildland ecosystems, and management options for these systems. The populations and associated damage from many forest insects and disease can cycle in and out of epidemic conditions where losses are often spectacular. In contrast, certain forest diseases are rather insidious and are constantly applying stress to trees.

Currently WWETAC and cooperators are investigating several aspects of insect and disease activity in western wildlands. These include:

• Characterizing root- and heart-rot diseases of Pacific island forests
• Interactions of native bark beetles and climate change
• Interactions of forest pathogens and climate change
• Potential interactions with forest insects and fire activity
• The role of insects in the mortality of trees surviving immediate effects of fire
• Early detection of forest stress
• The inclusion of insects and diseases in the westwide threat/risk mapping tool
• The fungal associates of the red turpentine beetle
• Fire, bark beetles, and salvage logging in the Greater Yellowstone Ecosystem
• Pathways and risk assessment of emerald ash borer movement into and within the Western United States
• Estimating insect distributions in Alaskan landscapes
• Improved early detection for the Mediterranean pine engraver, Orthotomicus erosus, an invasive bark beetle
• Aspen decline rapid threat assessment
• Developing an interior west-wide model to predict present and future climatic influences on Armillaria root disease in the USA
• Mapping forest composition and structure in the Pacific Coast States with gradient nearest neighbor imputation (GNN)
• A national early warning system for environmental threats
• Sudden oak death and fire
• Evaluating interactions between insect infestations and fire extent and fire severity: A preliminary investigation in Washington and Oregon
• National environmental threat assessment maps (NETAM)
• Applying population ecology to strategies for eradicating invasive forest insects
• Mexican bark beetle atlas
• Western Forestry Leadership Coalition threats to western private forests
• Annotated Bibliography of Climate and Bark Beetles of Western Forests
• Landscape-scale enhanced mountain pine beetle and climate change threat assessment
• Wildland Environmental Threat Assessment GeoService
• Adapting and improving Swiss needle cast management tools to incorporate climate change projections
• Synthesis of effects of insect-caused tree mortality on fire characteristics
• Developing biological control methods for the goldspotted oak borer (GSOB), Agrilus coxalis (Coleoptera: Buprestidae)
• Are the introduced parasites of larch casebearer (Coleophora laricella), still present in the Blue Mountains, Oregon?
• Assessment review of remote sensing technologies for threat detection
• Applied resistance breeding for forest trees workshop
• Genetic characterization of guava rust (Puccinia psidii): Evaluating pathways of spread and assessing future threats

In this work WWETAC strives to not only understand the likelihood and magnitude of insect and disease events in wildland systems but also the consequences of the events on values associated with the affected system. For example, insect activity in high-elevation lodgepole pine in the Rocky Mountains may be expected to kill 20 percent of the standing basal area over the next 25 years. So, what does that mean in terms of effects on values people hold for these forests? Without the latter information, our knowledge of the consequences of the event are unclear, and thus appropriate management responses are difficult to formulate.