Managing old-growth forests

All forests are dynamic; they cannot be preserved in a static condition. Management actions help sustain desired forest conditions and their associated values into the future. To function well as rare habitat for plant and animal species and to protect their structural complexity and unique natural characteristics, old-growth forests need to be managed within the context of the larger forest landscape. Management of old-growth forests and adjacent lands may involve: prescribed burning for forest types that require natural disturbance processes for tree regeneration; control and removal of exotic species; monitoring damage due to blowdowns; designing special harvest plans for lands around and between old-growth forests; conducting research in old-growth and old forests; and monitoring changes in old-growth forests compared with harvested forests.

Many of the above management activities will be required in order to ensure that the often small and isolated patches of remaining old-growth forest continue to serve important roles in the larger forested landscape. Without this work, old-growth forest values may diminish over time or old-growth forests in Minnesota may simply be museums of what was, rather than integral parts of a healthy forest ecosystem in the future.

DNR envisions an old-growth forest network of designated sites on state lands surrounded and connected--where practical--with forests being harvested at longer time interval using extended rotation forestry (ERF). This network could change over time. For example, if an old-growth forest were destroyed, then a similar one would be found to replace it.

Typical timberland lacks old forest conditions, once found in 51% of Minnesota's forests. By surrounding scattered old growth forests (OG) with forests cut when trees are older (extended rotation forests, or ERF), old forest conditions are created on larger areas. Now animals and plants that need older forests to survive can colonize and move through the modern forest landscape in larger numbers (arrows indicate their movement).

A managed old white and red pine forest near Hill City, Aitkin County, resembles old-growth forests in the size of trees, the result of harvesting using extended rotation forestry.

DNR works to maintain healthy, diverse, and productive forests to serve a wide range of values: timber production; habitat and species preservation; wildlife conservation; scenic beauty; recreation and hunting; watershed health and fishing. As part of this work, DNR is responsible for tracking the status of Minnesota's forests. Managing a network of protected old-growth forests on state lands represents an investment in the future, one of the foundation stones on which sustainable forest management is built. The timber harvested each year on state lands and the creation of old-growth forest reserves are some of what is happening in the state's forests to maintain sustainable conditions.