Even-aged silvicultural system: a silvicultural system that is designed to regenerate and maintain an even-aged stand. Clearcutting, seed tree, and shelterwood are even-aged systems.
Hazard: the degree to which the characteristics of a tree or stand make it vulnerable to damage. It is equivalent to susceptibility.
Incidence: the proportion of damaged or affected trees within a stand or area.
Risk: the probability and expected severity of damage as determined by a function composed of host susceptibility; suitable environmental conditions (both combined equate to hazard); plus pathogen proximity, abundance, and virulence.
Reserves: the retention of live or standing dead trees, pole size or larger, on site following harvest for purposes other than regeneration. Reserves can be uniformly distributed as single trees or left in small groups, and they can be used with any silvicultural system.
Residuals (residual trees): trees left standing after harvesting.
Seed trees: trees left standing to provide seed sources for natural regeneration. Selection is usually on the basis of good form and vigour, the absence of serious damage by disease, evidence of the ability to produce seed, and wind firmness.
Stand dynamics: the study of changes in forest stand structure over time, including stand behavior during and after disturbance.
Uneven-aged silvicultural system: a silvicultural system designed to create or maintain and regenerate an uneven-aged stand structure. Single-tree and group selection are uneven-aged silvicultural systems.