| Fire is a common, recurrent, and integral component of many forest ecosystems. Prescribed fires are set for a number of reasons, including the reduction of brush competition, the elimination of advance regeneration, and the abatement of damage attributable to insects, pathogens and vertebrates. Fire causes changes in soil physical properties, soil microclimate, soil nutrient status, and soil biology. The occurrence of dwarf mistletoe, Arceuthobium spp., is influenced by fire. Damage attributable to Rhizina undulata Fr. is increased after prescribed burning. Damage caused by other pathogens may be decreased by removal of susceptible hosts. Fire affects vertebrates primarily by alterations to food and cover. Vertebrate pests often favour the site and vegetational characteristics created by fires. Populations of insects resident in slash may be temporarily reduced by prescribed burning. Underburning shows promise for direct control of seed and cone insects in seed production areas, and for elimination of understory trees which promote survival of western spruce budworm, Choristoneura occidentalis Freeman. Fire should be used in wilderness areas, where appropriate, to maintain pre-suppression stand structures and minimize risk to forest pests. (Abstract shortened by UMI.). |
