[Mapping and Assessing Terrain Stability Guidebook Table of Contents]

Results and recommendations

The results and recommendations should be clearly stated in plain language so that forestry personnel fully understand the planning/management implications. Included should be:

The results and recommendations must also state whether proposals for clearcutting and construction of excavated or bladed trails will be in compliance with the Timber Harvesting Practices Regulation. For example:

Documentation of any inherent limitations of the TSFA

The recommendations must be clearly written so that forestry personnel fully understand what needs to be done. They should address by segments/areas along the falling boundary, reserve areas and interior of the cutblock or road sections:

As well, they should identify any additional investigations or other expertise that is needed (e.g., windthrow assessment, geotechnical engineering design of specific sites, snow avalanche assessments, hydraulic design or rock slope assessments).

The results and recommendations should be supported by a rationale, including:

The report should indicate whether a professional or a designate need be on site during road construction or deactivation. Typically an on-site specialist is required if:

Methods of describing cutblocks, gullies, streams, roads, and adjacent areas in TSFA reports


Gullies and streams



Accepted standard terminology should be used in TSFA reports to avoid confusion or misinterpretation. The following are the conventions in common use for this type of work in the forest sector:

(If the author chooses to use another convention, he or she should state what convention that is.)

Maps should use the cartographic conventions specified by the Terrain Classification System for British Columbia and the Guidelines and Standards for Terrain Mapping in British Columbia to indicate map reliability.

Appendices and attachments

Presentation of information will depend to some extent on the specific requirements of the client (e.g. format requirements) and the manner in which the TSFA report is submitted. For example, if the report is submitted along with the forest development plan documents, other information relevant to the assessment may already be in the forest development plan (e.g., stream classifications, terrain classification/stability mapping, 1:20 000 location maps, etc.). On the other hand, if the TSFA is a stand-alone document, or is being forwarded for review or other information purposes, it may be helpful to attach some of these other documents in full or in part.

Typical attachments include the following:

Reports in low hazard areas

A TSFA report can be abbreviated where an on-the-ground inspection (required for road and cutblock location) determines that, for selected road location, the assessed terrain has a likelihood of landslide initiation no more severe than low. A report rationale must be included to explain why an area is determined to have a low likelihood of landslides. Sufficient attachments, such as maps at 1:5000 to 1:10 000 and other items as listed above, must be included to clearly identify the areas traversed.

Limitations of TSFAs


A TSFA depends on surface features and natural exposures observed during the field visit, supplemented by air photo interpretation and evaluation of topographic maps and other available information. This type of assessment does not include subsurface investigation or measurement of the engineering properties of materials. It is, by nature, a qualitative assessment based on the professional's training, observational skills and experience in similar terrain. Prediction of terrain stability is based on an understanding of past and present geomorphic processes and the extent to which they are influenced by forestry operations. Terrain stability predictions are more accurate for some types of terrain and certain types of instability than for others.

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