The forest licensee review also comments on the following issues:
forest cover constraints
The amount of area that can be harvested at any time is constrained by the need to wait for adjacent areas to green-up to stated forest cover requirements. The licensee review says that areas excluded from the timber harvesting land base can be used to meet these cover requirements, but in the Forest Service analysis this only occurred in the visually sensitive zones. The result is a conservative estimate of timber supply.
older forest cover requirements
The Forest Service base case did not include an allowance for the retention of older forests since it was assumed that other reductions from the timber harvesting land base would accomplish these objectives. However, when considering requirements for biodiversity under the Forest Practices Code, according to the licensee review, old growth requirements should vary by species to take into account the fact that pine is considered mature at 81 years and other species at 121 years.
four-pass harvesting system
The Forest Service analysis assumed a maximum 25 per cent disturbance within a management unit at any time; in other words, four harvesting passes would be required. The licensee review states that this is a conservative approach, given that most licensees use a three-pass system. However, even with a four-pass system the base case initial harvest level could be maintained for at least 90 years.
harvest rate
The licensee review notes that increasing or decreasing the initial harvest by various amounts does not impact the long-term harvest level.
non-recoverable losses
The licensees accept the Forest Service estimates of non-recoverable losses (from fire, insects and disease) as reasonable. The importance of giving priority to salvage operations to minimize these losses is stressed.
