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.

Dwarf mistletoe.

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

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.