Spatial Modeling of Harvest Constraints on Wood Supply Versus Wildlife Habitat Objectives

摘要

We studied the effects of spatial and temporal timber harvesting constraints on competing objectives of sus-taining wildlife habitat supply and meeting timber harvest ob-jectives in a boreal mixedwood forest. A hierarchical modeling approach was taken, where strategic and tactical level models were used to project blocking and scheduling of harvest blocks. Harvest block size and proximity, together with short-and long-term temporal constraints, were adjusted in a facto-rial manner to allow creation of response-surface models. A new measure of the habitat mosaic was defined to describe the emergent pattern of habitat across the landscape. These models, together with multiple linear regression, were used to provide insight on convergence or divergence between spatial objectives. For example, green-up delay (defined as time re-quired before a harvest block adjacent to a previously logged block can be scheduled for harvest) had an adverse effect on the amount of annual harvest area that could be allocated and blocked spatially, and habitat supply responded in an oppo-site direction to that of wood supply, where caribou, moose wintering, and marten habitat supply increased when harvest blocks were further apart, maximum block size smaller, and both a green-up delay and mesoscale stratification were ap-plied. Although there was no "solution space" free of conflicts, the analysis suggests that application of the mesoscale strati-fication, together with a diversity of harvest block sizes and a between-harvest block proximity of 250 rn, will perform rela-tively well with respect to wood supply objectives, and at the same time create a less fragmented landscape that better re-flects natural forest patterns.