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• Silviculture


  The art and science of controlling the establishment, growth, composition, health, and quality of forests and woodlands to meet the diverse needs and values of landowners and society on a sustainable basis
• Silvics


  The study of the life history and general characteristics of forest trees
• Cultural Treatment


  The manipulation of vegetation to meet silvicultural objectives
• Extensive Forestry


  The practice of forestry on a basis of low operating and investment costs per acre, typically on a longer rotation
• Intensive Forestry


  Managing a forest to obtain a high level of productivity through the application of the best techniques of silviculture and management, typically on a shorter rotation
• Silvicultural System


  A planned process spanning a whole rotation whereby a stand is tended, harvested, and reestablished
• Rotation


  In even-aged systems, the period between regeneration establishment and final cutting. In uneven-aged systems, the approximate time it takes to regenerate the entire area within a stand, or the age of the oldest planned cohort within a stand
• Even-aged System


  A planned sequence of treatments designed to maintain and regenerate a stand with one age class. The range of tree ages is usually less than 20 percent of the rotation
• Two-aged System


  A planned sequence of treatments designed to maintain and regenerate a stand with two age classes
• Uneven-aged System


  A planned sequence of treatments designed to maintain and regenerate a stand with three or more age classes
• Succession


  A series of dynamic changes by which organisms replace one another through a series of plant community (seral) stages
• Disturbance


  Any relatively discrete event in time that disrupts ecosystem, community, or population structure and changes resources, substrate availability, or the physical environment
• Density Dependent Mortality


  The process whereby a tree loses vigor and dies due to competition for light, nutrients, or water
• Density Independent Mortality


  The process whereby a tree dies due to stochastic disturbance events
• Stand Dynamics


  The study of changes in forest structures and composition over time and the processes that cause these changes
• Stand Initiation


  A stage of stand dynamics in which individuals and species continue to appear for several years following a disturbance, and stands are young and dense
• Stem Exclusion


  A stage of stand dynamics whereby after several years new trees stop appearing and already established individuals begin to die; those that survive grow and begin to manifest differences in height and diameter
• Understory Reinitiation


  A later stage in stand development when forest floor herbaceous species, shrubs, and advanced regeneration all appear and survive in the understory because large dominant trees are dying due to insects, disease, lightning, windthrow, or other causes, forming canopy gaps and freeing up site resources
• Old Growth


  The late successional stage of forest development characterized by heterogeneous stand structural elements such as large live trees, dead trees, diverse composition, multiple age classes, and complex canopy characteristics
• Structure


  The horizontal and vertical distribution of the physical components of a forest stand
• Shade Tolerance


  The relative capacity of a plant to become established and grow beneath overtopping vegetation
• Stand Density


  A quantitative, absolute measure of tree occupancy per unit of land area in such terms as numbers of trees, basal area, or volume
• Relative Stand Density


  The ratio, proportion, or percent of absolute stand density to a reference level defined by some standard level of competition
• Stocking


  An indication of growing-space occupancy relative to a preestablished standard
• Growing Stock


  All the trees growing in a forest or in a specified part of it, usually commercial species meeting specified standards of size, quality, and vigor
• Sapling


  A tree, usually young, that is larger than a seedling but smaller than a pole
• Pole


  A tree between the size of a sapling and a mature tree
• Site Quality


  The productive capacity of a site, usually expressed as volume production of a given species
• Site Index


  A measure of actual or potential forest productivity expressed in terms of the average height of a certain number of dominants and codominants in the stand at an index age
• Crown


  The part of a tree or woody plant bearing live branches and foliage
• Stratum


  A distinct layer of vegetation within a forest community
• Crown Class


  A class of tree based on crown position relative to the crowns of adjacent trees
• Emergent


  Trees with crowns completely above the general level of the main canopy receiving full light from above and from all sides
• Dominant


  Trees with crowns extending above the general level of the main canopy receiving full light from above and partly from the sides
• Codominant


  Trees with crowns forming the general level of the main canopy receiving full light from above and comparatively little from the sides
• Intermediate


  Trees with crowns extending into the lower portion of the main canopy but shorter in height than the codominants; they receive little direct light from above and none from the sides
• Overtopped or Suppressed


  Trees of varying levels of vigor that have their crowns completely covered by the crowns of one or more neighboring trees
• Stand


  A contiguous group of trees sufficiently uniform in age class distribution, composition, and structure, and growing on a site of sufficiently uniform quality, to be a distinguishable unit
• Age Class or Cohort


  Trees originating from a single disturbance
• Stand Composition


  The proportion of each tree species in a stand