Commercial Thinning. Investigations in western Washington suggest that mid-rotation thinning, in combination with cavity-tree retention and/or creation can accelerate development of late successional habitat features in younger forests (Xxxxxx et al. 2003, Xxxxx 2004, Xxxxx and Xxxx 2004)). Thinning and cavity-tree retention have been suggested as a primary management technique for enhancing the forest understory for northern flying squirrels (Glaucomys sabrinus) (Xxxxx and Xxxxxxx 1995, Xxxxx 2000), the primary prey species of spotted owls in western Washington (Xxxxxxx et al. 2004). Thinning of second-growth coniferous forests in western Washington has been proposed by Xxxxxx (1992) as a critical element of an overall landscape strategy for creating and maintaining terrestrial wildlife habitats in younger managed forests. Thinning of Xxxxxxx-fir/western hemlock forests allows for competitive release of canopy dominants and shade- tolerant understory trees, eventually resulting in multiple canopy layers, increases in canopy depth, and enlargement of tree crowns (Xxxxxx et al. 1991); these enhancements are associated with murrelet and spotted owl habitat and tend to increase niche availability for breeding birds. Typically, with a harvest rotation age of 45 years or younger, commercial thinning operations would not be conducted. By incorporating a 60-year, or longer, harvest rotation into the forest management plan, Everett could commercially thin qualifying conifer-dominated stands. This activity generally results in healthier conifer stands with larger tree diameters and wider spacing. The latter characteristic allows spotted owls to move through these stands as they disperse, and to forage more effectively. With the inevitable defect that develops in older stands that are left free to grow, these stands also have the potential to develop into spotted owl prey habitat. This is one of the potential benefits to spotted owls from implementing a 60-year rotation age for the LCT forest lands. Specific management considerations and actions related to the decision to conduct commercial thinning are described below. As conifer stands reach age 30 to 40 years, canopy coverage, shrub vigor, and forest health are assessed. Generally, commercial thinning will be employed to reduce excessive overstory canopy coverage to 60% where usage of ground-based yarding equipment is possible (slopes ≤ 35%) and log prices are sufficient to produce positive net revenue. Older stands will also be simi...
Commercial Thinning. A partial cut where trees of a merchantable size and value are removed to provide an interim harvest while maintaining a high rate of growth on the remaining, well-spaced, final crop trees. Used to capture volume likely to succumb to competition pressures and be lost to forest health damaging agents. Commercial timber permit (CTP) A timber disposition issued under Section 22 of the Forests Act authorizing the permittee to harvest public timber.
