Due to pressure to raise forest productivity in Sweden, there are proposals to apply more intensive forestry methods, but they could have potentially large effects on biodiversity. Here we report a compilation and evaluation of the extent and significance of such effects. We evaluated potential effects on biodiversity by introducing intensively fertilized Norway spruce plantations as a management option in Swedish forests with low conservation values on insects, vascular plants, lichens, bryophytes, and red-listed species. Due to a lack of specific studies addressing this question, we based the evaluation on a combination of available and appropriate empiric and anecdotic knowledge; literature data, and expert judgments largely available in species data bases. Our evaluations suggest that such forests will only harbor species that are common and widespread in conventionally managed stands and that species of conservation interest will be lacking, due to the low heterogeneity and light intensity of even-aged monocultures with dense canopies, short rotation times and low availability of coarse woody debris. Effects at the landscape scale are more difficult to evaluate, but will be dependent on the area utilized and the conservation value of sites used.
We conclude that negative effects on biodiversity can be reduced if: (1) only land with the lowest conservational value is utilized; (2) plantations are spatially arranged to minimize fragmentation of the landscape; (3) the quality and quantity of key structural elements (e.g., coarse woody debris, old living trees and snags) are maintained at the landscape level; and (4) management intensity is relaxed on other land. For effective implementation of these measures, legislative frameworks and policy instruments need to be adjusted and new models for planning and monitoring need to be developed.