Soil Conservation Guidebook

Table of contents

4 Permanent vs. temporary: classifying access structures

The determination of whether an access structure should be classed as permanent or temporary is often contingent on: a) whether the structure is suitable for rehabilitation treatments, given the type of material through or with which it is constructed, and b) the period of time for which the structure will be required for forest management activities following harvesting.

The suitability of component materials for rehabilitation depends on such factors as: use of ballast, depth of excavation into unfavourable subsoil, soil texture, opportunities for stockpiling and retrieving topsoil, and amount of coarse fragments in the soil. For example, on many coastal sites where rock work or ballasting is commonplace during road and landing construction, the large component of rock in the road or the depth of subgrade ballast used may make it unsuitable for rehabilitation. In the northeast of the province, the rehabilitation of roads constructed on very fine-textured soils may not be practical, given the high costs of treatments that would be necessary to restore soil productivity.

Guidelines may be established by regional or district staff to help identify which site and soil conditions are suitable for rehabilitation treatments.

If a road is not required for too long a period following harvesting, such that a crop of merchantable trees could be established on it by the time the adjacent cutblock area was ready for the next harvest, the road should be considered for rehabilitation.

For example, consider a spur road that is likely to be used to provide access for silviculture treatments for a 10-year period following harvesting. If the next harvest were to occur when the trees on the cutblock were 120 years old, the trees planted on the area of the rehabilitated road would be 110 years old. It is reasonable to assume that the trees on the former road would be of a merchantable size, and therefore could be harvested concurrently with the rest of the cutblock. In this case, the road would be proposed as a temporary access structure. Of course, to avoid a delay in regenerating the area occupied by the temporary road, it may be more beneficial to rehabilitate the road sooner, enabling it to be planted concurrently with the rest of the cutblock. Access to carry out the silviculture measures could be gained through an alternative means, if necessary (e.g., by a permanent road running through or adjacent to the cutblock, or through use of ATVs).

The on-block portions of main haul roads and branch roads (i.e., roads that pass through a cutblock to access other existing or planned cutblocks, or other forest management sites such as stand management areas or recreation sites) should be identified as permanent access roads.

On-block spur roads (i.e., those that end within a cutblock) should be considered temporary access structures, unless

Most gravel pits and borrow pits are likely to be permanent due to the inherent difficulty in restoring site productivity on these excavated structures.

Excavated or bladed trails are temporary access structures, unless they are required to be retained as permanent logging trails (e.g., to facilitate multiple entries in partial cutting operations). Non-excavated logging trails (e.g., main skid trails) may be identified on a silviculture prescription as temporary access structures. This will most often occur in situations where use of these trails could result in prescribed maximum soil disturbance limits being exceeded prior to their planned rehabilitation. For more details, see the section, "Temporarily exceeding the maximum allowable level of soil disturbance in the net area to be reforested." If construction of a proposed backspar trail is likely to result in soil disturbance that satisfies the definition for an excavated or bladed trail, the backspar trail should be designated as a temporary access structure. Otherwise, the presence of an excavated or bladed trail would have to be specifically accounted for in the silviculture prescription.


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