Protecting Residual Trees and Site Productivity
Damage to residual stems during thinning operations typically occurs during felling and skidding activities and can be minimized by:
- Selecting an operator who has experience performing thinning treatments.
- Conducting an on-site preharvest meeting with the buyer and operator.
- Carefully planning transportation systems (i.e., forwarding rows and skid trails) to accommodate equipment as well as future harvest entries.
- Reusing existing transportation systems where feasible.
- Using care in felling and skidding of trees.
- Limiting harvests of shallow-rooted species to frozen or dry conditions to minimize root damage.
- Avoiding harvesting in the spring as the bark is more susceptible to sloughing off.
- Identifying trail locations for skidders and/or forwarders which are as straight as possible to minimize rubbing of residual trees. The sharper the skidding or winching angle, the shorter the log should be.
- Minimizing trafficking in areas where young regeneration is present.
- Creating appropriate contract language which specifies residual stand protection requirements.
- Closely monitoring the timber sale as it progresses.
Beyond minimizing damage to the residual stand, it is also important that harvest entries do not negatively impact the long-term productivity of the site. In particular, those entries should be done in a way that minimizes soil damage, such as compaction, rutting, or erosion. The following practices can be used to minimize soil damage during harvest entries, where appropriate:
- Restricting equipment to designated transportation systems.
- Harvesting sites during either dry or frozen ground conditions.
- Spreading tops and limbs on skid trails to minimize impact of equipment.
- Installing water bars or other erosion control devices along the transportation system in areas where erosion may occur.
- Creating appropriate contract language which specifies residual stand protection requirements.
- Closely monitoring the timber sale as it progresses.
