Incorporating landscape pattern features in a spatial harvest model

Xianhua Kong
1999
The primary objective of this research is to solve area-based harvest scheduling problems which not only specify the timing and location of harvesting activities, but also predict the changes in landscape structure in terms of remnant patchiness. Remnant patches are considered to be ecologically important in maintaining biodiversity on the landscape. Based on existing knowledge and experience of spatially-constrained harvest scheduling and landscape pattern models, I developed the Landscape
more » ... d the Landscape Harvesting Scheduling model (LHS) to meet the requirements of this research. LHS has four objectives related to timber harvesting: 1) opening size, 2) timber flow, 3) road construction cost, and 4) maximum disturbance rate (denoted by percentage of total planning area). It also has three objectives related to landscape pattern: 1) remnant patch size, 2) patch shape, and 3) inter-patch distance. Each objective is represented as an individual objective. All objectives are evaluated by penalty costs. A simulation annealing algorithm was used to randomly generate solutions and converge on those with minimum total penalty costs. A number of model runs were made under different management scenarios to: 1) determine the effects of adjacency constraints (opening size, green-up period) on timber production and landscape structure, 2) determine the effects of the remnant patch constraints on the changes in landscape structure, and 3) compare the simulation results to those from the harvest simulation model, ATLAS - A Tactical Landscape Analysis System. The simulation results show that the Relaxed Adjacency (RA) rule causes less timber reduction than the Strict Adjacency (SA) rule, and that timber reduction caused by exclusion period constraints can be offset by larger opening size limit constraints. The results also show that existing spatially-constrained harvest models cause forest landscapes to lose large remnant patches after about 60% of the total planning area is cut. It is concluded that without the remna [...]
doi:10.14288/1.0089284 fatcat:wafpa6puszh65jqjtkrofdhgiy