[Spacing Guidebook Table of Contents]

Maintaining stand level biodiversity

Landscape level biodiversity objectives should be considered and incorporated into silviculture prescription or stand management prescription objectives. Stand level practices are carried out to maintain or promote a component of the historic levels of stand attributes. Prescriptions should address the management of stand attributes and timber production during the entire rotation. Some wildlife species may require consideration beyond the usual habitat features considered at the stand level. Individual species management may take precedence over the standard stand level procedures for maintaining biodiversity during spacing. Specific considerations for biodiversity should be clearly referenced in spacing contracts. Refer to the Managing Identified Wildlife Guidebook and Guidelines for Maintaining Biodiversity During Juvenile Spacing for additional information.

Species management

Critical habitats are those of identified wildlife (see the Managing Identified Wildlife Guidebook) as well as ungulate winter ranges and habitats of species of regional significance. Such areas may be designated wildlife habitat areas (WHA). Specific provisions for maintaining wildlife habitat areas or other significant habitats should be included in sub-regional, landscape, and stand-level plans.

Guideline 14

Where special management or emphasis areas have been identified, and the existing guidelines or the Managing Identified Wildlife Guidebook do not provide sufficient information or guidance, contact the Ministry of Environment, Lands and Parks staff or regional forest habitat specialist.

Stand level management to maintain biodiversity

Wildlife trees, vertical and horizontal structural variability, and the maintenance of native tree composition are important features to address when planning for stand level biodiversity in a spacing operation. Stand structure and composition objectives should be identified at the landscape unit level. Consider these features when developing silviculture prescriptions, stand management prescriptions, and contracts, and when implementing stand activities. Figure 2 shows an example of a spaced stand with biodiversity attributes maintained. Refer to the Biodiversity Guidebook, and Guidelines for Maintaining Biodiversity During Juvenile Spacing.


The Silviculture Practices Regulation states that a tree which is not a significant competitor with a crop tree should not be felled in a spacing treatment.

A tree is not a significant competitor with a final crop tree when it is one or more of the following:

Wildlife trees

A wildlife tree is a standing dead or live tree with special characteristics that provide valuable habitat for conservation or enhancement of wildlife.

Wildlife tree management includes both the retention of suitable wildlife trees at the time of harvest and silvicultural activities, and the recruitment of suitable replacement wildlife trees over the rotation period.

Generally, the safest and most operationally feasible method for managing wildlife trees is to leave a mixture of live and dead standing trees in a clumped distribution (reserves). The location and size of the reserves in a stand will depend on specific site conditions such as availability of high value wildlife trees, and wind firmness. The amount of wildlife tree area required for any specific unit depends on the level and distribution of existing and planned harvesting on the surrounding landscape. Areas to consider for wildlife tree reserves may include the edge of the stand, areas that are difficult to access, or less productive areas. This location can be chosen to minimize the impact of the mandatory no-work zone. Where possible wildlife tree reserves and no treatment zones should be described in a stand management prescription and identified on an accompanying map. Refer to the Biodiversity Guidebook for more information on wildlife trees.

Guideline 15

Variable stocking levels

Maintaining a variety of stocking levels will provide for vertical and structural variability in the stand. Both unthinned areas and areas of wider spacing should be used to provide variability. Wide spacing in 2 to 8 ha patches could be used to promote understorey vegetation. Significant areas of varied density may need to become a separate standards unit in a silviculture prescription or stand management prescription.

Unthinned areas may be necessary for security cover and thermal cover for wildlife. Such areas provide physical concealment from hunters and predators. Some wildlife, such as deer, prefer to be near cover at all times. Provision of cover close to forage and water increases the utility of these resources.

A visual buffer, also known as a visual screen, should exist along main and secondary roads in areas with high populations or hunting pressure of big game species. A visual buffer may be provided by topography or vegetation (Figure 3) that blocks the viewing of the interior of the treatment area. The buffer size depends on the specific site conditions. The width of the buffer should be sufficient that a person or animal walking along the interior edge of the buffer is at least 90 per cent screened from view from the road.

Leaving small patches or strips of unspaced trees may also be required to create hiding cover within the stand within the stand or around important wildlife areas such as wildlife trees and riparian zones.

Whenever possible, there should be multiple objectives for areas left unspaced. These objectives can include roadside visual buffers for wildlife, riparian area buffers, and buffers for reducing fire risk. However, roadside buffers along heavily travelled roads may not be appropriate for wildlife thermal cover.

Unspaced areas greater than 50 metres wide may be useful as treatment controls. Future retrospective comparisons of untreated areas to treated areas may be possible if the untreated area was originally homogeneous with the area being treated.

Guideline 16

Maintaining understorey species composition

Understorey shrubs such as willow and elderberry provide forage for deer and moose, particularly in winter. Berry producing shrubs provide important forage for bears, some songbirds, and small mammals. Shrubs also provide shelter for a variety of birds, snowshoe hare, squirrels, chipmunks, and other small mammals. The full range of native understorey plants and plant communities should be maintained across the landscape unit.

Guideline 17

Maintaining native trees composition

A stand with several tree species will tend to support more species of animals than a stand that contains only one tree species. Where possible maintain the full range of native conifer and hardwood tree species originally found in the stand.

Guideline 18

Riparian areas

Riparian areas will often require special management. Willows, red-osier dogwood, and other shrub species provide important winter forage for moose and deer. Riparian areas provide feeding and nesting grounds for many varieties of wildlife. Waterside vegetation will help lower water temperature, and fallen trees can create important habitat diversity for fish and other aquatic organisms. Refer to the Riparian Management Area Guidebook for additional information.

Guideline 19

Wildlife trails

Wildlife trails may be permanent or temporary. Grizzly and black bear make well defined, permanent trails used for travel and as home range markers. Moose, deer, and elk may also make permanent trails that follow less difficult lines of travel—for instance, along ridge tops or through drier areas in swamps.


Large wildlife experience difficulty in moving through stands with large continuous piles of slash. By spacing stands when trees are younger, large accumulations of slash may be avoided. If large, continuous slash piles are unavoidable, the creation of gaps through the slash may facilitate wildlife movement.

Directional falling allows the cut trees to lie flatter on the ground, allowing easier access through the stand. With the slash closer to the ground, it reduces the fire hazard and decomposes faster. Areas identified as winter range may require additional work to reduce the slash depth to an acceptable level.

Slash should be removed from water bodies (streams, rivers and lakes) and wildlife trails. The slash can be redistributed through the stand or placed in small piles. Small slash piles provide potential shelter habitat for birds and mammals. Ideally, such slash piles should consist of a few very large stems. Where forage production is an objective, consider selective piling of slash and burning.

Guideline 20

Not all desirable habitat features will be present in any one stand. At a minimum, each stand will be managed for its existing attributes, or the attributes that can be created at each stage in its development. In some stands, less emphasis may be placed on maintaining biodiversity if:

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