Commercial thinning to provide harvest stability to forests with an unbalanced age class distribution

Maintaining harvest stability while minimizing volume losses to mortality is a challenge in forests characterized by an unbalanced age-class distribution with an overabundance of "over-mature" and too few 'mature' stands. In many areas with this situation, emphasis is on harvesting over-mature stands and regenerating them quickly at defined density and stocking levels to minimize the eventual wood supply downfall. However, silvicultural activities in stands at other stages of development are often neglected. Wood supply analysis of a spruce-fir forest with the above characteristics indicated that both harvest stability and maintenance of the total volume harvested could be obtained by commercial thinning in mature stands. In addition, the treatment may have other benefits such as habitat protection. Defining the specifics of the treatment is required to move from consideration at the strategic level to operational implementation.