Soil Rehabilitation Guidebook

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Soil Rehabilitation Guidebook Table of Contents]

Appendix 1. Examples of rehabilitation plans

Anticipated rehabilitation of temporary landings

Within the soil conservation section of the silviculture prescription, a description of the critical site factors for rehabilitation and a statement of the rehabilitation objectives must be included. The following is an example of these statements:

Problem analysis and critical site factors for rehabilitation

The five landings identified to be temporary access structures will be rehabilitated to restore soil productivity and prevent surface soil erosion.

Site factors affecting rehabilitation success include:

Successful rehabilitation will be achieved by conserving topsoil during construction and replacing it during rehabilitation, and by decompacting the soils with a winged subsoiler. There are no hazards from altered drainage or off-site effects.

No special problems are anticipated for vegetation establishment on this site in the SBSwk1 (see Map 1). Because of the low surface soil erosion hazard, a selection of native species will be established to gain more familiarity with their potential for rehabilitation.

Detailed treatment objectives

  1. To conserve a 20 cm layer of topsoil during construction, and replace it during rehabilitation.

  2. To decompact the soils to restore the original rooting depth of 40 cm.

  3. To respread ash from burned piles and form a discontinuous cover of unburned fine- and medium-sized logging debris to limit access and improve long-term nutrient status.

  4. To establish at least 50% cover of indigenous vegetation including alder, sedge and lupine to control surface erosion, maintain soil structure, and improve nutrient status.

  5. To reforest the treated areas with lodgepole pine to achieve the same free growing stocking standards as specified for the surrounding standards unit.

Within the logging plan, statements must be included about the rehabilitation treatments, schedules and monitoring plans. The following sections are examples of these statements:

Rehabilitation treatments

Construction of the landings: Stumps and large woody debris from the landing site will be piled to the side of the landings. The topsoil (upper 20 cm) and forest floor that has to be removed will be placed in piles at convenient locations, separate from the stumps and woody debris. Any subsoil that is excavated will be used to level the site. Large organic debris or tree tops will be added to the debris pile.

Rehabilitation treatment: After harvesting, the debris piles will be burned. Topsoil and ash piles will be respread over the landings. Unburned woody debris will not be mixed into the topsoil in such a manner that loose, unplantable microsites are created.

After spreading the topsoil and ash, decompaction of the landings will be achieved by subsoiling to a depth of 50 cm with a winged subsoiler. We expect soil moisture conditions will be suitable for subsoiling in September and October, but they will be monitored before moving equipment to the site. The soils will be dry enough that they shatter when worked, but not so dry that they turn to powder. Woody debris may be distributed as a discontinuous (approximately 10% cover) layer with an excavator so the decompacted surface does not have to be driven on.

A mix of equal parts by weight Sitka alder, bronze sedge and perennial lupine from a local seed source will be established to improve nitrogen status, restore soil structure and control surface erosion. Seed will be dry broadcast immediately after subsoiling at a rate of 30 kg/ha. No fertilizer application is planned because it may interfere with the success of the native plants in occupying the site.

Lodgepole pine will be planted using the same specifications as the adjacent standards unit.

Schedule

Rehabilitation treatments will be conducted at the earliest possible time after logging and debris disposal have been completed and when soil moisture conditions are such that the soil is in a friable condition. Seeding will take place immediately after respreading topsoil and decompacting, unless timing is inappropriate (e.g., not in mid-summer). Planting will occur in the spring after the soil treatments are complete. Regeneration delays of up to two years post-harvest may be necessary to allow for debris disposal or due to unsuitable weather conditions for rehabilitation treatments.

Map 1. Map, showing landings to be rehabilitated.

Anticipated rehabilitation of temporary excavated and bladed trails

Within the soil conservation section of the silviculture prescription, a description of the critical site factors for rehabilitation and a statement of the rehabilitation objectives must be included. The following is an example of these statements:

Problem analysis and critical site factors for rehabilitation

All approved excavated and bladed trails (temporary access structures) will be fully rehabilitated upon completion of harvest to restore soil productivity and prevent surface soil erosion.

Site factors affecting successful rehabilitation include:

Soil disturbance will be minimized by harvesting on snowpack in late winter and early spring. The depth and width of cut will be minimized, and a mix of snow and fill will be used to construct the trails. Compaction will be reduced by working under frozen soil conditions.

Successful rehabilitation will be achieved by ensuring that sidecast topsoil is readily retrievable, and mixing of the topsoil and any unfavorable substrate is minimized, replacing the topsoil during rehabilitation, and by decompacting the running surfaces.

Vegetation establishment on this site in the MSdk will be affected primarily by calcareous subsoils and moisture stress. Because of the high surface soil erosion hazard, and as recommended by the district range agrologist, a well-tested seed mix of agronomic grasses and legumes will be used to reduce erosion on all exposed mineral soil. Visual quality concerns are low.

Detailed treatment objectives

  1. To conserve a 30-cm layer of topsoil during construction, and minimize the excavation of unfavorable subsoils by restricting the depth of cut to not greater than 40 cm and the width of cut to not greater than 2 m.

  2. To decompact all running surfaces to a depth of 20 cm, replace topsoil, and pull debris over the surface to control soil erosion.

  3. To ensure that subsurface water flow patterns are maintained by creating an outsloping condition on all decompacted running surfaces, recontouring the slope to approximate its original shape, and restoring all drainage channels.

  4. To establish 80% cover of agronomic grasses and legumes by seeding to prevent resettling of the decompacted soils and to control surface erosion.

Within the logging plan, statements must be included about the rehabilitation treatments, schedules and monitoring plans. The following sections are examples of these statements:

Rehabilitation treatments

Construction of the skid roads: Skid road construction will be carried out with an excavator. Stumps and large woody debris removed from the running surface will be placed downslope of the skid roads in such a manner that they act as a trap to prevent excavated soil from ravelling down the slope.

Snow will be removed from the inner track area and compacted where the fill will be placed. Salvaged topsoil will then be placed on the snow, and covered with more snow to form the running surface.

Rehabilitation treatment: Concurrent with the end of harvesting, the excavated and bladed trails will be completely rehabilitated by ripping the bladed portion of the running surface to ensure that it is outsloping, then carefully replacing any subsoil against the cut. Finally, topsoil will be retrieved from within the fill and used to recontour the slope. This will leave the original trail surface in an outsloping condition, overlain by a loosened layer of topsoil at least 25 cm deep.

A discontinuous layer (approximately 20% cover) of woody debris will be spread on the surface.

Exposed mineral soil surfaces will be revegetated with a seed mix containing 15% perennial rye, 10% intermediate wheatgrass, 25% creeping red fescue, 15% orchardgrass, 10% Canada bluegrass, 20% Alsike clover, and 5% alfalfa by weight. It will be broadcast at 40 kg/ha once the snow has melted. This high rate of seeding reflects the need for vigorous vegetation cover to restore soil productivity and prevent surface soil erosion. Fertilizer (19-18-18) will be added at the time of seeding at a rate of 200 kg/ha.

Schedule

Rehabilitation will occur concurrently with the end of harvesting operations. Hand seeding will be carried out as soon as the snow has melted.

Map 2. Map of bladed trails to be rehabilitated.


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