Evaluation of Selected Mechanical Clearings in the Northwest Region in 2003


John Hallett


Mechanically created clearings have been constructed in forested and shrub areas throughout the ACA’s Northwest Region to increase browsing opportunities for ungulates. The purpose of this project was to determine the comparative duration of usage amongst sites, what ungulate species preferred each clearing site, and if certain vegetation types were better candidates for clearing. Successful sites would be those with significantly more browse (stems/ha) and or more ungulate usage (pellet groups/ha) than that observed in control (un‐cleared) areas. Plots were established within clearings and the number of stems, heights, and browsing of each preferred shrub species was recorded. An estimate of the number of ungulate pellet groups per hectare for each surveyed clearing was also tallied. Bear Creek Phase 2 clearings had very little ungulate usage. Browse production on the hand‐cut willow area was significantly greater than that observed in the mechanical clearings and control area. North Smoky clearings did not have significantly greater browse production or utilization than the control area. Nitehawk clearings C and D had much higher levels of moose usage (pellet groups/ha) than clearing B and control areas.

Findings from these clearing surveys result in some future considerations. Candidate sites should be surveyed to determine the need for habitat enhancement. Areas with low ungulate numbers should not require mechanical clearings, unless it is determined that the lack of browse is the reason for the low numbers. If the potential clearing site is dominated by willows, then a clearing method that results in some portion of the stem to remain is preferable to mechanical clearing that shears willows at ground level. A provincial ACA protocol to outline the circumstances when mechanical clearing is an appropriate habitat enhancement tool should be developed. A standardized method of clearing evaluation should also be developed which includes a way to measure clearing success as a habitat enhancement activity. 

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