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U.S. Forest Service
Caring for the land and serving people

United States Department of Agriculture

Western Bark Beetle Strategy Glossary

Aggregating pheromone - chemical compound released by an insect (male or female) to attract others of its species.

Bark beetles - group of beetles, mainly of the family Scolytidae, whose adults bore through the bark of host trees to lay their eggs, and whose larvae tunnel and feed under the bark.

Generation time - the time it takes for an organism to develop from egg to reproductive adult.

Host specific - one species (e.g. bark beetle) lives on or within another specific host species (e.g ponderosa pine).

Larva - an individual that emerges from the egg and differs markedly from the adult form. Bark beetle larvae are white, legless grubs.

Life history - the combined activities and requirements of a species throughout its life, including patterns of development, environmental or habitat requirements. mating strategies, predators and their avoidance, etc.

Limiting resource - an essential material required by an organism such that limited quantities of the material limit the ability of the organism to successfully complete its life cycle and reproduce.

Mass attack - the aggregation of bark beetle adults on one host tree in sufficiently large numbers to overcome the host’s defense mechanisms.

Natural Recovery - The use of natural processes to revegetate an area after a disturbance (such as bark beetle infestation) and the acceptance of resulting conditions, even though it may take many years to attain stocked forested conditions.

Niche - the place where an organism lives, including habitat, food resources, nesting resources, behavioral patterns of the organism, and a variety of other resources that are species specific.

Pupa - the stage of insect development between the last larval instar and the emergence of a new adult. Typical adult features begin to form.

Salvage harvesting - removal of trees that are dead, dying, or deteriorating to utilize remaining merchantable wood before it becomes worthless.

Sanitation harvesting - removal of infected or infested dead or damaged trees, or of susceptible trees, to prevent or reduce the spread of the infestation. Sanitation harvesting is intended to remove currently infested trees where beetle life stages still remain under the bark. This is the most efficient form of beetle management. The objective is to reduce residual beetle populations available for subsequent attack within the stand or in adjacent susceptible stands.

Resilience - The ability of a social or ecological system to absorb disturbances while retaining the same basic structure and ways of functioning, the capacity for self-organization, and the capacity to adapt to stress and change.

Restoration - The process of assisting the recovery of an ecosystem that has been degraded, damaged, or destroyed.

Tree hazard - Tree hazard is the likelihood of property damage or personal injury from tree failure.