Forest cover dynamics in the Pacific Northwest west side: regional trends and projections

The objectives of this paper were to (1) analyze recent rates of transition s among forest cover types on private timberland, (2) identify differences by ownership class, and (3) project future changes under different scenario s related to current policy issues in the Pacific Northwest. Timber harvest s are the dominant class of disturbance on private timberland in western Or egon and Washington. Net changes in forest type areas depend on the relativ e mix of natural and human-related forces. Transitions among forest types a fter harvest may be planned, as in conversion of red alder (Alnus rubra Son g.) to the commercially preferred Douglas-fir (Pseudotsuga menziesii (Mirb. ) franco.), or stochastic successional changes, such as reversion of distur bed areas to red alder in the absence of intervention. Projected areas of D ouglas-fir and red alder were notably different under a scenario without ha rvests versus a scenario in which the rate of partial harvesting is increas ed. Areas of Douglas-fir were projected to increase under selected scenario s for both industrial and nonindustrial private ownerships. Conversely, are as of red alder are projected to decrease under selected scenarios and for both ownerships.