I
Immature	trees or stands that have grown past the regeneration stage, but are not yet mature.
Immature timber	stands of timber where the age of the leading species in a stand is less than the specified cutting age. Cutting ages are established to meet forest management objectives.
Impact assessment	a study of the effect of resource development on other resources.
Improvement cutting	the removal of trees of undesirable species, form or condition from the main canopy of the stand to improve the health, composition and value of the stand.
Increment	the increase in diameter, basal area, height, volume, quality or value of individual trees or stands during a given period.
Increment borer	a tool used to extract a core of wood from a living tree for the purpose of studying the annual growth rings of the tree.
Increment core	that part of the cross section of a tree extracted by an increment borer. Used to determine tree age and growth pattern.
Incremental silviculture	that part of the cross section of a tree extracted by an increment borer. Used to determine tree age and growth pattern.
Increment core	a term that refers to the treatments carried out to maintain or increase the yield and value of forest stands. Includes treatments such as site rehabilitation, conifer release, spacing, pruning, and fertilization. Also known as intensive silviculture. See Basic silviculture.
Indicator species	species of plants used to predict site quality and characteristics.
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Industrial operation	operations such as land clearing, timber harvesting, timber processing, mechanical site preparation and other silvicultural treatments, mining, and road construction.
Initial attack	the action taken to halt the spread or potential spread of a fire by the first fire fighting force to arrive at the fire.
Initial mature inventory	that portion of the existing total mature forest inventory which is available for harvest. This portion reflects all management constraints that are necessary to protect the environment and other forest uses and varies with the constraints identified for each option.
Inoperable lands	lands that are unsuited for timber production now and in the foreseeable future by virtue of their: elevation; topography; inaccessible location; low value of timber; small size of timber stands; steep or unstable soils that cannot be harvested without serious and irreversible damage to the soil or water resources; or designation as parks, wilderness areas, or other uses incompatible with timber production.
Insloping	shaping the road surface to direct water onto the cut side of the road.
Integrated resource management (IRM)	the identification and consideration of all resource values, including social, economic, and environmental needs, in land use and development decision making. It focuses on resource use and land use and management, and is based on a good knowledge of ecological systems, the capability of the land, and the mixture of possible benefits.
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Integrated resource use	a decision making process whereby all resources are identified, assessed and compared before land use or resource management decisions are made. The decisions themselves, whether to approve a plan or carry out an action on the ground, may be either multiple or single use in a given area. The application of integrated resource management results in a regional mosaic of land uses and resource priorities which reflect the optimal allocation and scheduling of resource uses.
Intensive silviculture	see Incremental silviculture.
Intermediate	intermediate trees have crowns below, but still extending into, the general level of the canopy and receive a little direct light from above but none from the sides.
Interpretive forest site	a designated forest site and ancillary facilities developed to interpret, demonstrate, or facilitate the discussion of the natural environment, forest practices, and integrated resource management.
Intertree distance	the distance between tree boles, usually used in the context of thinning. Recommended guidelines for intertree distances are established for different thinning programs depending on site variables, the species and age of trees, and management objectives.
Inventory, forest	a survey of a forest area to determine such data as area, condition, timber, volume and species for specific purposes such as planning, purchase, evaluation, management or harvesting.
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J
Joint administration	a term referring to the joint powers of various provincial ministries. It is also used to refer to their involvement in certain aspects of strategic and operational planning.
Judicial review	a review of a decision by a court authorized and conducted under the Judicial Review Procedure Act primarily concerned with the fairness of the procedures used to make a decision, whether or not the decision maker was acting within his or her jurisdiction, and errors of law.
Juvenile spacing	a silvicultural treatment to reduce the number of trees in young stands, often carried out before the stems removed are large enough to be used or sold as a forest product. Prevents stagnation and improves growing conditions for the remaining crop trees so that at final harvest the end-product quality and value is increased. Also called precommercial thinning.
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K
Key area	a relatively small area selected because of its location, use, or grazing value as a monitoring point for grazing use. It is assumed that key areas, if properly selected, will reflect the overall acceptability of current grazing management.
Key species	forage species that must, because of their high degree of use, be considered in the management program.
Keystone species	a species that plays an important ecological role in determining the overall structure and dynamic relationships within a biotic community. A keystone species presence is essential to the integrity and stability of a particular ecosystem.
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