Spatial modeling of forest patterns can provide information on the potential impact of various management strategies on large landscapes over long time frames. We used LANDIS, a stochastic, spatially-explicit, ecological landscape model to simulate 120 years of forest change on the Nashwauk Uplands, a 328,000 ha landscape in northeastern Minnesota that lies in the transition between boreal and temperate forests. We ran several forest management scenarios including current harvesting practices, no harvests, varied rotation ages, varied clearcut sizes, clustered clearcuts, and landowner coordination. We examined the effects of each scenario on spatial patterns of forests by covertype, age class, and mean and distribution of patch sizes. All scenarios reveal an increase in the spruce-fir (Picea-Abies) covertype relative to the economically paramount aspen-birch (Populus-Betula) covertype. Our results also show that most covertypes occur in mostly small patches <5 ha in size and the ability of management to affect patch size is limited by the highly varied physiography and landuse patterns on the landscape. However, coordination among landowners, larger clearcuts, and clustered clearcuts were all predicted to increase habitat diversity by creating some larger patches and older forest patches. These three scenarios along with the no harvest scenario also create more old forest than current harvesting practices, by concentrating harvesting on some portion of the landscape. The no harvest scenario retained large, fire-regenerated aspen-birch patches. Harvests fragment large aspen-birch patches by changing the age structure and releasing the shade-tolerant understory species. More sapling forest, and larger sapling patches resulted from the shortened rotation scenario.
Bibliographical noteFunding Information:
This work was supported by funding from the Minnesota Forest Resources Council, Minnesota Department of Natural Resources, Minnesota Forest Industries, Audubon Society, and The Nature Conservancy as part of the Spatial Analysis of Forest Landscape Conditions project. Valuable comments and criticisms were supplied by the project’s strategy and technical teams, and John Zasada of the US Forest Service North Central Research Station in Grand Rapids, MN.
- Boreal forest
- Disturbance size
- Forest management
- Spatial patterns