[Silviculture Prescription Guidebook Table of Contents]
The silviculture prescription must show the results of an assessment of the fire hazard and fuel loading expected after harvesting and, where fire hazard abatement is anticipated, specify the actions to be undertaken and the approximate time frame for completion of the work. Hazard abatement must be consistent with higher-level plans and conducted in accordance with a burning plan or smoke management plan, and with the Open Burning Regulation where required.
- To show how increased fire hazards such as concentrations of slash resulting from forest practices will be mitigated to an acceptable level, while recognizing soil disturbance limits, coarse woody debris objectives and the need to accommodate other forest resources.
The guidebook Fire Management provides assistance in quantifying fire hazard and describing hazard abatement methods and should be consulted when the use of prescribed fire is proposed.
The site sensitivity to prescribed fire classification and coarse woody debris objectives will influence hazard abatement options. Where prescribed burning is proposed, the silviculture prescription must state the maximum amount by which the forest floor may be reduced by prescribed burning activities. See the section on soil conservation and the guidebook Hazard Assessment Keys for Evaluating Site Sensitivity to Soil-Degrading Processes for details.
Figure 21. Fire hazard abatement example.
A silviculture prescription must specify free growing stocking standards, specify the regeneration methods that will be used, and prescribe silviculture treatments to be undertaken to achieve the desired stand structure, stocking standards and species composition while keeping with the objectives of the chosen silvicultural system. Silviculture prescription must be consistent with a five-year silviculture plan and should be planned and conducted in a manner that ensures the soil resource is protected.
- To show that harvesting and silviculture treatments are compatible with each other to form a treatment regime capable of achieving a free growing stand at or near target stocking levels and meeting management objectives for the area.
All silviculture treatments, and alternate treatments to be carried out in the event of reasonably foreseeable failures, must be provided.
Silviculture treatments with potential adverse effects on soil, water or other forest resources should include the objectives for the treatment, thus eliminating any confusion over the intent of a treatment and potential impacts on a particular site.
Factors that may be restrictive to stand establishment (including such factors as WCB limitations on areas made hazardous by wildlife tree retention) or stand growth should be identified in this section and measures to address them included in the prescription.
The prescription must describe the method that must be used for, and soil conditions that must exist during site preparation and the objectives of the treatment, by SU if necessary. Where the possibility of a treatment failure can be foreseen, such as where broadcast burning is prescribed, an alternate treatment must be prescribed. The Site Preparation Guidebook provides guidance for prescribing site preparation activities.
Note: The Silviculture Practices Regulation imposes restrictions on the use of livestock for site preparation.
Where broadcast burning or the burning of slash accumulations is prescribed, all work must be conducted in accordance with the Fire Management Guidebook. Reduction of the forest floor by prescribed burning must not exceed the limits specified in the prescription (see the section on soil conservation).
The regeneration method must be stated by SU. This could be natural, artificial or a combination of the two (e.g., natural regeneration with fill planting as required or planting supplemented with natural or advanced regeneration).
Where natural regeneration has been prescribed, the prescription must contain sufficient justification detailing why natural regeneration is suitable to achieve the stocking requirements stated in the prescription by the regeneration date.
Where the free growing stand is to be achieved by means other than 100% natural regeneration, the prescription must indicate the species mix and approximate number of trees to be planted per hectare. If the prescribed planting density is less than the target stocking standard, describe how (number and species) natural fill-in or advanced regeneration is expected to increase stocking to at least the target stocking standard.
Where other factors such as seedlot, stock type, season of planting or microsite selection are critical to the success of the prescription, they should be included as part of the regeneration prescription.
Use of advanced regeneration
A prescription may call for the retention of advanced regeneration or other trees (e.g., wildlife trees) to meet specific management objectives. Where these trees are expected to count toward stocking requirements, the characteristics for acceptability must be known and described, by layer if appropriate. Unless otherwise described in the silviculture prescription, the free growing acceptability criteria will be as provided in the Establishment to Free Growing Guidebook. For species not included in that guidebook or when deviating from that guidebook, criteria for acceptability must be provided in the prescription.
Where competing vegetation may be a problem to seedling survival or performance, the prescription must provide the general method of treatment (manual, mechanical, ground chemical, aerial chemical or biological/livestock), the anticipated timing of the treatment and any constraints to the treatment (e.g., timing, moisture conditions).
It may be appropriate to include a brief summary of vegetation species and an estimate of its current and future competition (i.e., competition index) to better rationalize the choice of treatment, if any.
Where the failure of a treatment or failure to complete a treatment (e.g., chemical treatments) is foreseeable, an alternate treatment must be provided.
Note: The Silviculture Practices Regulation imposes restrictions on the use of livestock for brushing and site preparation.
Where spacing is anticipated for stocking control or to meet other resource objectives, the prescription must indicate the general method (manual, chemical or mechanical) and approximate timing of the treatment. If spacing is planned for other purposes, the rationale for, and method of treatment must be provided. Disposal of spacing slash should be addressed in the fire hazard abatement section.
Note: Spacing prescriptions to address a maximum density issue must also state a minimum and maximum density per hectare that will occur following treatment.
Where pruning is required to manage white pine or otherwise achieve free growing requirements, or to achieve other objectives of the prescription, the objective and approximate timing of the treatment must be provided. Disposal of pruning slash, if any, should be addressed in the fire hazard abatement section.
Where fertilization is expected to be necessary to achieve a healthy, free growing stand, the prescription must provide the method (ground or aerial) and approximate timing of treatment.
Note: The Silviculture Practices Regulation imposes restrictions on fertilizer use in community watersheds.
Inclusion of proposed post free growing treatments in a silviculture prescription is optional. The prescription does not impose any obligation to conduct these treatments but their inclusion may be appropriate to provide clarification or justification for the prescription.
Figure 22. First example of silviculture treatments.
Figure 23. Second example of silviculture treatments.
The silviculture prescription must specify the stocking standards for each standards unit. The Establishment to Free Growing Guidebook provides guidance on species selection and stocking standards.
Stocking will be measured in accordance with the Silviculture Surveys Guidebook unless otherwise stated in the silviculture prescription.
These systems create openings that require regeneration to be established and achieve free growing status. The following stocking requirements must be included in the silviculture prescription.
Preferred and acceptable species
Preferred and acceptable tree species for the area must be specified. Silviculture treatments must be directed toward establishing and maintaining the preferred species component.
In cases where management objectives dictate only a portion of the free growing stand may be comprised of certain species, state which species are restricted in their contribution to stocking and the per cent of the free growing stand they may compose.
Minimum allowable horizontal distance
Specify the minimum allowable horizontal distance between trees (minimum inter-tree distance or MITD) of preferred or acceptable species for those trees to be considered well-spaced.
Target stocking standard (TSS)
Specify the number of healthy, well-spaced trees of preferred and acceptable species per hectare desired on the area.
Minimum stocking standard (MSSpa)
Specify the minimum number of healthy, well-spaced trees of preferred and acceptable species per hectare that must be on the area in order to consider the area satisfactorily stocked.
Minimum stocking standard of preferred species (MSSp)
Specify the minimum number of healthy, well-spaced trees of the preferred species per hectare that must be on the area in order to consider the area satisfactorily stocked.
Specify the maximum number of years from the commencement of harvesting (or approval of the prescription if it is for damaged or destroyed timber or trespass) allowed to establish at least minimum stocking. This is commonly referred to as the "regeneration delay."
Note: For backlog silviculture prescriptions, this period is measured from the commencement of treatments rather than the approval date of the prescription. Whenever this assessment date is to be measured from a point in time other than the commencement of harvesting, the prescription should state clearly when the time frame commences.
Free growing assessment period
- Early free growing: Specify the earliest time, in years from the commencement of harvesting (or prescription approval if it is for damaged or destroyed timber or trespass), that the area may be declared free growing. When regeneration is achieved in a shorter period than the regeneration delay, the prescription may be amended to move the earliest free growing date ahead a corresponding period.
- Late free growing: Specify the latest time, in years from commencement of harvesting (or prescription approval if it is for damaged or destroyed timber or trespass), that a free growing stand must be established on the whole of the net area to be reforested.
Note: For backlog silviculture prescriptions, these periods are measured from the commencement of treatments rather than the approval date of the prescription. Whenever these assessment dates are to be measured from a point in time other than the commencement of harvesting, the prescription should state clearly when time frames commence.
Specify the maximum number of coniferous trees allowed per hectare. This figure is specified as “countable” stems allowed per hectare in accordance with the Establishment to Free Growing Guidebook.
Post-spacing density range
Specify the maximum and minimum number of well-spaced coniferous trees per hectare to be retained after spacing to meet maximum density requirements.
Specify the minimum height, by species, that crop trees must attain in order to be classified free growing.
Crop tree to brush ratio
Specify the height that a free growing crop tree must attain relative to competing vegetation within a 1 m radius of the tree’s trunk.
Other survey criteria
Where advanced regeneration or trees that vary from free growing survey criteria presented in the Establishment to Free Growing Guidebook are expected to contribute toward stocking at the free growing assessment, the criteria for acceptability should be stated with the stocking standards. See the regeneration portion of the preceding section for additional discussion.
For uniform seed tree, uniform shelterwood or other even-aged partial cutting silviculture systems not covered by the section above, the silviculture prescription must include:
- all requirements outlined in the section on stocking standards
- stand structure and composition goals
- planned basal area or stand density to be left after harvesting.
Stand structure goals may be quite complex for some shelterwood systems or as simple as leave-tree acceptability criteria in the case of uniform seed tree systems. Planned residual basal area must be stated in the silviculture prescription. Minimum residual BA will be specified by the cutting authority document.
When prescribing single tree selection systems, stocking standards are required by layer as defined in the Operational Planning Regulation. Four layers are described—mature, pole, sapling and regeneration—although it is possible to have one or more layers absent and recorded as such. The following standards must be provided (see section on stocking standards for definitions):
- preferred and acceptable species for each layer
- minimum allowable horizontal distance between trees for the pole, sapling and regeneration layers
- target stocking standard for all layers
- minimum stocking standard of preferred and acceptable species for each layer
- minimum stocking standard of preferred species (only) for each layer
- regeneration date
- free growing assessment periods
- maximum density for the sapling layer only
- minimum and maximum number of well-spaced trees to be left in the sapling layer after maximum density spacing
- minimum free growing tree height for the regeneration layer only
- crop tree to brush ratio to be achieved by the sapling and regeneration layers
- planned residual basal area per hectare
- any survey criteria hat vary from the Establishment to Free Growing Guidebook or Silviculture Surveys Guidebook or similar information that is required by the district manager.
Commercial thinning is a form of partial cutting where regeneration is not the objective. For this type of harvesting, stand structure and composition goals must be provided. Stocking standards include the planned residual basal area and stand density per hectare, by species if necessary, and any leave-tree characteristics important for achieving the objectives of the prescription. Timing for the next entry should also be described.
In most cases, the management zone of a riparian management area will be a separate SU and will have different stocking requirements than the rest of a cutblock.
There are many different management objectives possible for these sites and many variations on treatment options. The objectives for these zones must be clearly stated and the expectations for reforestation clearly described. Further guidance is provided in the Riparian Guidebook.
Complex SUs contain distinctly different site (BEC) units, which cannot be mapped. Prescriptions for tree species selection or silviculture treatments may be varied for each component of the complex but must be described clearly in the prescription. For example, a commitment to “plant Douglas-fir on the ridges and redcedar in the draws” is sufficient provided the boundaries of the units can be identified on the ground.
Stocking standards may be varied within a complex unit but the boundaries for standards must be readily identifiable in the field in order to judge the success of the prescription.
The total area under the prescription must be provided, preferably in the tenure identification section at the beginning of the prescription.
The net area to be reforested must be summarized, by SU, preferably on the prescription map.
Total area under the prescription is all the area inside the marked boundary of the cutblock. It includes all productive area (standards units) reserve patches of timber or immature trees, natural non-productive area (rock, swamp, brush, alpine forest), created non-productive area (planned and existing roads, landings, gravel pits) and individual areas of non-commercial brush greater than four hectares.
Note: Planned or existing roads include those roads previously constructed, those that will be constructed under a road permit or a cutting permit authorized under the Act, and all non-status roads. It does not include roads with tenures granted by other acts, such as public highways.
Net area to be reforested is the area on which the licensee is responsible for establishing a free growing crop of trees. This figure is the sum of SU areas; that is, the total area minus human-caused non-productive areas (normally permanent access structures), reserve patches of timber or immature trees that are large enough to stratify and map, natural non-productive areas that are large enough to stratify and map, and non-commercial brush areas greater than 4 ha that are not deemed to be the obligation of the licensee (these non-commercial brush areas should be mapped as NCBr strata.) Non-productive or non-commercial areas that are too small to stratify are included in the SU area.
Figure 24. Clearcut or patch cut example of free growing stocking standards.
Figure 25. Uneven-aged example of free growing stocking standards.
Note: This example represents the regeneration and final removal cuts of a uniform shelterwood system.
Figure 26. Even-aged partial cut example of free growing stocking standards.
The silviculture prescription map must provide an accurate visual representation of those physical features, ecological units, standards units and other resource features that have been referred to in, or have a bearing on, the prescription. All maps should comply with Ministry of Forests’ cartographic standards, as documented in the Visual Identifier Standards Guide (B.C. Ministry of Forests. 1994. Visual Identifier Standards Guide. Technical and Administrative Services Branch, Victoria, B.C.).
Map scale for silviculture prescriptions should be 1:10 000 or larger, unless otherwise approved by the district manager.
The scale and level of detail required on maps will depend on topography, block size and the complexity of management on the area. Mapping should concentrate on dominant site units with minor units shown where they impact management requirements. Whether it is necessary to delineate very small units depends on their impact on the prescription.
In most cases, two or more maps will be required in order to keep the maps legible. It is recommended that one or more maps be used to display ecosystem strata, sensitive areas and any other critical site factors relevant to the prescription (e.g., slope, sensitivity to soil disturbance, stream classification, riparian management areas, VQOs and range improvements) and the second to display SUs.
Silviculture prescription maps must include administrative information, resource and ecological information, final management units and area summaries.
- tenure identification — at least the licence number, cutting permit (for major licensees) and block number must be provided
- location — the block must be tied to a recognizable feature as a permanent control point. UTM co-ordinates must be provided for permanent control points
- legend — the legend must describe all mapped objects and strata
- scale, north arrow, map sheet and air photo numbers
Resource and ecological information
- Cutblock and other administrative boundaries (e.g., lot numbers, leases and research plots, in or adjacent to the area).
- Streams and wetlands within and adjacent to the area and the riparian class, reserve zone and management zone for each.
- Lakes within and adjacent to the area and any lakeshore reserve and management zones.
- Any wildlife habitat areas, forest ecosystem networks, wildlife tree or other reserves.
- Adjacent forest cover.
- Existing roads, landings and trails (forest road names and mileage should be shown).
- Biogeoclimatic ecosystem classification (BEC).
- Areas of different soil sensitivity ratings must be mapped whenever the different ratings result in different maximum allowable disturbance levels.
- Any other resource feature or zone that is referred to in the prescription or higher-level plans guiding the prescription. These might include sensitive areas (as described in the earlier section on management objectives and consistency with plans), areas of rock or unstable soils, range improvements, water monitoring, research installations, VQOs or other interpretative units.
- Proposed road and landing locations if critical to the success of the prescription.
- Changes in slope, aspect or other site characteristics that will dictate different management objectives, soil disturbance or stocking standards must be shown as map strata.
Final management units
The map must clearly indicate the SUs by which the prescription will be judged.
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