Fire, Competition and Forest Pests: Landscape Treatment to Sustain Ecosystem Function

Fire, competition for light and water, and native forest pests have interacted for millennia in western forests to produce a countryside dominated by seral species of conifers. These conifer-dominated ecosystems exist in six kinds of biotic communities. We divided one of these communities, the Rocky Mountain Montane Conifer Forest, into 31 subseries based on the ability of shrubs and forbs to predict soil-moisture regimes and conifers to predict soil-temperature regimes. This classification facilitated correlation of fire regimes, ecophysiological theory, and genetic theory to create an analytical framework for assessing ecological change. Using this tool we assessed likely ecologic impacts resulting from the introduction of white pine blister rust. Because large-scale disturbance, fire and cutting, have been greatly reduced in western ecosystems most heavily impacted by blister rust, their restoration will require large-scale replacement of the role of fire. Reduced net primary productivity is a natural consequence of forest succession. As forests age, photosynthetic and water use efficiencies decline, while decomposition in the standing biomass increases. Most forests reach a point where carbon release exceeds carbon sequestration–the “pathologic rotation.” Effective management of these forces will require exact knowledge, ecosystem by ecosystem, of resource availability and system processing efficiencies. Using the classification presented, theories of competition, ecophysiology, genetics and pest behavior can be combined to examine site-specific ecosystem behavior. Finally, a preliminary plan to achieve process sustainability is presented.