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GUIDELINES for . . .
Spacer graphic Developing Stand Density Management Regimes

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The importance of forest-level plans

      This section has emphasized that the stand-level density management decision should not be made without reference to forest-level objectives and the strategies designed to attain those objectives. The existence and quality of the forest-level plan(s) pertinent to a stand will determine the quality of the stand-level density management decision. However, higher level plans may not be in place for all of the land base and few forest-level analyses have been undertaken with the objective of determining strategic silvicultural opportunities. Useful information on forest-level objectives and strategies can be found in TSR documents, however, the forest estate modelling undertaken for the TSR is designed to quantify timber supply as a consideration in AAC determination. Stand-level decision making may benefit from additional forest-level modelling studies that have a focus on identifying strategic silvicultural opportunities, as part of the development of a strategic silviculture plan at the forest level.

      Readers interested in more information about forest-level planning and timber supply analysis should review the literature presented in "References."

Identifying strategic silvicultural opportunities that help
meet forest-level objectives

      Identifying silviculture activities which assist the meeting of forest-level objectives requires, at least, an assessment of existing information pertaining to the forest level. It may stop there. Forest-level modelling is neither necessary nor recommended if there are sufficient materials and expertise available to formulate silvicultural opportunities.

      An understanding of forest-level concepts is important, and it is recommended that, where necessary, silviculture practitioners draw on the expertise and advice available within and outside the Forest Service.

      It is recommended that the identification of silvicultural opportunities which help meet forest-level objectives follow a two-step process:

      1. Obtain and assess existing forest-level analyses.
      2. Conduct additional forest-level modelling analysis.

      The first step is essential. Completion of the second step may not always be possible, nor is it always necessary.

      For each, an understanding of forest-level concepts is important, and it is recommended that expertise in forest-level concepts or forest-level modelling be sought, where necessary.

Identifying silvicultural opportunities through the assessment
of existing forest-level information

      To better understand silvicultural opportunities for your forest estate, review all relevant existing materials. You can expect this review to provide useful insights and possibly sufficient information for identifying strategic silvicultural opportunities.

      The results of the most recent TSR timber supply analyses and the AAC rationales provide a rich source of information on forest-level objectives, at least those perceived to impact timber supply.

      An especially valuable section of the timber supply analysis document describes the sensitivity of the forecast harvest flow to changes in key variables, some of which might be affected by density management decisions. For example, the TSR timber supply analysis may note that short-term timber supply is increased substantially if the minimum harvest age is reduced by five years. This might be interpreted as an opportunity to use density management to decrease the age at which high value forest products (e.g., sawlogs) can be obtained from the stand.

      In addition to reviewing documents, spreadsheet models that incorporate timber supply sensitivity analysis from the TSR can be useful for estimating the impact of stand density management activities on short- and long-term timber supply.

Forest-level modelling

      Forest-level modelling is an analytical process that will assist the identification and quantification of strategic silvicultural opportunities.

      A forest-level analysis may help determine a set of silvicultural regimes that best meets the combined objectives, subject to harvest flow requirements and forecast silviculture budgets. This set of regimes constitutes the strategic silvicultural opportunities for the forest.

      Forest-level models can help determine the sensitivity of the forest-level objectives to each strategic silvicultural opportunity. This information may be used in the process of allocating funds to projects.

      Any such modelling exercises undertaken should be integrated with other exercises such as those being conducted as part of formal planning processes.

      Table 3 in "Density management planning tools" lists commonly available forest estate models. Often a considerable investment of time and resources is necessary before operators acquire the necessary experience to be able to use such models competently. An alternative is to make use of services available within and outside the Forest Service.

      Three important considerations need to be made when conducting forest-level analyses for the purpose of assisting the determination of silvicultural regimes that are designed to impact the timber supply for the forest estate:

      1. Assumptions should be consistent with, and follow from, those made in timber supply analyses supporting AAC determinations.
      2. Forest-level analyses should consider the desired harvest flows for the entire forest estate or sustained yield unit, rather than for a sub-unit only.
      3. Little is known about the future with certainty, and models provide imperfect views of reality. All results should therefore be treated with caution and be used only as an aid to decision making - not as the decision maker itself.

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Copyright 1999 Province of British Columbia
Forest Practices Branch
BC Ministry of Forests
This page was last updated January 1999

Comments to: Tim Ebata <Tim.Ebata@gems8.gov.bc.ca>