|GUIDELINES for||. . .|
|Developing Stand Density Management Regimes|
For the purposes of this document, forest-level objectives can be classified as timber objectives, non-timber objectives and employment objectives. For each class of objectives, the forest-level planning process develops one or more strategies to attain the objectives. Both the objectives and their associated strategies are specified temporally (i.e., over the planning horizon) and geographically.
Forest-level timber objectives may state the quantity, quality and timing of timber production from the forest estate. These objectives could be expressed as a schedule of harvests.
The strategy devised to achieve this schedule will specify timber management actions, including harvesting parameters (e.g., species mix, log size, log quality) and silvicultural parameters (e.g., management regime, including rotation length).
Ideally, timber management objectives are determined with the assistance of timber supply analysis. While this might occur as part of the timber supply review (TSR), it may not, because the TSR is focused on supporting allowable annual cut (AAC) determination. Nevertheless, the timber supply analyses supporting the TSR, and the associated AAC rationales, may be the best sources of information available for determining timber objectives at the sustained-yield unit level.
A forest estate usually provides a large array of non-timber resource values.
Examples of non-timber values include stand and landscape features such as species occurrence, natural stand disturbance types, special wildlife habitat, riparian ecosystems, viewscapes, heritage artifacts and heritage opportunities, as well as amenities such as water production, food, shelter and recreational opportunities. Forest-level objectives describe how a resource or value will be managed (e.g., the desired future condition of each identified non-timber value).
The main strategies for realizing non-timber objectives are to wholly or partially preserve the pertinent area from timber harvesting, reduce harvesting intensity by distributing harvest areas throughout the landscape, lengthen rotations or specify an alternative harvesting method.
Other operational strategies may focus on post-harvesting treatments that control stocking, stand structure or composition.
Non-timber objectives are usually identified in higher level plans and are described in forest-level plans or TSR documents.
Employment objectives may be a consideration in forest-level planning, especially in management units with forecast reductions in timber harvest.
Most stand-level silviculture treatments, including density management treatments, provide local employment opportunities that can help to sustain the forestry workforce within communities. Consequently, silviculture programs are often specified as a strategy to attain employment objectives.
Objectives for creating local employment may be specified in land and resource management plans and forest-level plans.
Stand density management is only one of a number of possible silviculture practices capable of influencing forest-level factors. Any stand treatment which contributes to the achievement of forest objectives is a silvicultural opportunity. The structure (e.g., species, age class distribution, density) and site quality of the forest estate and the complexity of management objectives are the major determinants of silvicultural opportunities.
These may require silviculturists to consider a wide variety of treatment or regime options to satisfy management objectives.
Once density management opportunities have been identified, and stand treatment options have been selected and implemented in the forest, the biological effects should be evaluated periodically and compared with expected responses. Actual departures from expected results may require reconsideration of the silviculture options, opportunities or both. This adaptive density management approach encourages continuous validation of assumptions, and incorporation of new information and experience.
Copyright 1999 Province of British Columbia