Integrated Roles for Insects, Diseases and Decomposers in Fire Dominated Forests of the Inland Western United States

Abstract

Forest ecosystems characterizing much of the Inland Western United States occupy precarious, changing environments that can be moisture, temperature, and/or nutrient limited. Rapid vegetative adaptations to inherent change are critical to both plant community stability and to the survival of individual species. Biological decomposition processes are often constrained and natural wildfires represent an important recycling agent Recycling of resources is critical. It is proposed that native insect, disease and other decomposer activities, plus natural wildfire, historically provided coordinated biological and physical processes that were integral to carbon, nitrogen, and other nutrient cycling, and to rapid evolution and adjustment of native conifers (and of their ecosystems) in this dynamic environment Current conditions, as imposed by traditional harvesting and fire control over the last 100 years, plus the introduction of white pine blister rust in the early 1930s, have changed many native vegetative and microbial systems. Endemic insects and diseases have responded to these changes by increasing activities. Their effects counter many of the destabilizing actions of site deterioration, fuel accumulation, changes in species and genetic compositions, increased stand densities and impairment of recycling processes. At least in the short term, many ecosystems are now highly vulnerable to potential damage from high fuel wildfire and perhaps to the momentum of alternative biological decomposition processes. Genetic resources and other diversity components may be at especially high risk. Many current trends place future values in increasing danger until the course is changed. Adjusting cycling processes, stand density and species composition will often be more important than controlling individual pests when managing forest health for this region in the future.