Best Management Practices
The following section summarizes the recommended best management
practices for timber harvesting on karst terrain. As these are
summaries, you should also check out more detailed information
in the Karst
Management Handbook for British Columbia.
Low Vulnerability Areas
The following best management practices are recommended:
- Conduct safety briefings for appropriate personnel.
- Flag karst features and/or values within the operating area.
- If previously unidentified
karst features or values are encountered, modify or cease operations
until the features or values can be assessed. Notify the local
- Minimize exposing mineral soil as much as possible.
- Locate storage areas for fuel and other hazardous materials
off karst terrain or at least on low vulnerability karst
areas (except for daily fuel requirements).
Back to Top
Moderate Vulnerability Areas
In addition to the recommendations for low vulnerability areas, the following
best management practices are recommended on moderate vulnerability areas:
- Consider restricting harvesting to periods when the likelihood
of heavy rains and high runoff are low.
Consider developing site-specific procedures for
spaced, dense occurrences of minor surface karst features
(e.g., falling and yarding away from features, retaining non-merchantable
vegetation, removing logging debris from features, etc.).
In some cases it may be practical to treat a cluster of minor
features as a single unit.
Figure 7-1: Treating
a cluster of minor surface karst features as a single
- Avoid disturbing sideslopes and soil as much as possible
when harvesting around sinkholes that
do not require a reserve (e.g., fall and yard away, retain non-merchantable vegetation,
maximum suspension yarding). Harvesting sinkholes with >70%
sideslopes should be carried out very carefully due to the
for soil erosion.
- Where falling away from a sinkhole cannot be reasonably achieved,
and remaining trees threaten sideslope stability due to windthrow
potential, consider falling across the sinkhole if the tree
stem will span the feature and can be lifted without damaging
If removal will damage residual trees or sideslopes, leave
the section of stem spanning the feature, provided it is stable.
- Consider the following when trying to recover logging
slash and debris from sinkholes:
- Clean out debris only if it will not cause further disturbance.
- Avoid using heavy machinery if damage to sideslopes might
- Follow machine cleaning with hand cleaning if necessary.
- Leave naturally fallen trees.
- Do not remove stable natural material embedded in sinkhole
sideslopes or root systems that contribute to sideslope
- Keep the wheels or tracks of equipment at least 5 metres from
the edge of karst features. If not possible, keep wheels or tracks
parallel to the edge of features.
- Take appropriate measures to correct inadvertent water diversions
to prevent sediment transfer into subsurface environments.
- Use protective mats to minimize soil disturbance when hoe
- Keep skid trails and backspar trails to a minimum and located
away from surface karst features and cave entrances.
- Minimize the potential for soil disturbance through maximum
- Avoid fueling or servicing machinery near surface karst
features and cave entrances. Take appropriate measures
if spills occur.
Back to Top
High Vulnerability Areas
In addition to the recommendations for low and moderate vulnerability areas,
the following best management practices are recommended on high
- Minimize soil disturbance and maintain site productivity
on well-developed epikarst with shallow soils by considering
the use of:
- Partial-cutting systems
- Maximum or total suspension
- Rubber mats when hoe chucking
- Helicopter logging.
- When harvesting over caves known or suspected to have thin
- Project the outline of the cave to the surface.
- Avoid the use of heavy machinery.
- Assess the size and weight of the timber being felled.
- Fall and yard away from the underlying cave.
- Avoid decking logs over top of the cave.
- Avoid piling slash on exposed, well-developed epikarst;
use road prisms where possible.
- Attempt to remove fallen trees in or near significant
surface karst features or significant
caves if it won’t cause
further disturbance. (Use full suspension logging if possible.)
Back to Top