Abstract In the future, a significant proportion of Northern forests may become intensively
managed through the planting of monospecific stands of native or introduced trees,
and the use of multiple silvicultural treatments such as forest fertilization. Such an
intensification of management in selected parts of the landscape is suggested by different
zoning models, for example the Triad approach, which is under evaluation in some regions
of North America. In this study, based on Fennoscandian conditions, we predicted landscape-
scale extinction risks of five hypothetical model insect species dependent on fresh
dead wood from Norway spruce (Picea abies), by simulating colonizations and local
extinctions in forest stands. Intensified forestry applied to 50% of the spruce stands led to
strongly increased extinction risks of all species during the following 150 years. For one
species—the sun-exposure specialist—there were strong effects already after 50 years. The
negative effects of intensive plantation forestry could be compensated for by taking greater
biodiversity conservation measures in other managed forests or by setting aside more
forests. This is consistent with the Triad model, which is according to our analyzes an
effective way to decrease extinction risks, especially for the short-dispersing species and
the species associated with closed forest. A zoning of forest land into intensive forestry,
conventional forestry, and set asides may be better at combining increased timber production
and maintenance of biodiversity in comparison to landscapes where all production
forests are managed in the same way.