Managing old-growth forests

forester measuring treeThe DNR manages a 44,000-acre network of old growth forest sites on state-administered land.

The goal of the DNR’s old growth forest policy is to maintain a viable statewide network of high-quality old growth forest sites along with relatively undisturbed, natural-origin younger forests that will be managed to promote old growth characteristics in the future (i.e., future old growth). The DNR will manage this old growth forest network to maintain both its quality and the acreage necessary to:

  • Adequately represent old growth forests as an element of the state’s biodiversity;
  • Provide habitat needed for wildlife and plants associated with old forests;
  • Maintain benchmark sites for natural processes that we are only beginning to understand; and
  • Guarantee Minnesotans the opportunity to enjoy old growth forests now and in the future.

forester measuring tree with tape measure.To achieve this goal, the DNR strives to maintain or restore the integrity of old growth communities. Timber harvesting is not allowed in old growth forests (including salvage and timber improvements); wildlife opening and browse regeneration development cannot occur; pesticides cannot be used (except to protect against serious exotic threats); metallic mineral exploration is prohibited; and new road development is not allowed (with very few exceptions).

All forests are dynamic; they cannot be preserved in a static condition. Forest management activities help to achieve desired forest conditions. Old growth forests need to be managed within the context of the larger forest landscape to function well as rare habitat for plant and animal species, and to protect their structural complexity and unique natural characteristics. Management of old growth forests and adjacent lands may involve prescribed burning for forest removal of exotic species; managing herbivory; 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 to ensure that the 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 benefits may diminish over time or old growth forests in Minnesota may simply become museums of the past rather than integral parts of a healthy future forest ecosystem.

The DNR envisions an old growth forest network of designated sites on state lands surrounded and connected, where practical, with forests being managed to complement and support old growth forest values. This network could change over time. Designated old growth forests are protected as long as they maintain their old growth characteristics. If a protected forest loses its old growth features it can be replaced with another forest of similar quality outside the protected network.

History of old growth forest policy at DNR

The DNR has been working hard since the 1980s to preserve old growth forests. Important dates in the development and implementation of the DNR's old growth policy include the following:

1983 – Old growth forest issue emerges and the DNR begins policy discussions on how much and where to protect old growth forests using internal forestry and wildlife guidelines
1988 – DNR staff form the interdisciplinary Old Growth Forest Task Force to develop more specific old growth forest guidelines
1990 – DNR Commissioner approves the Old Growth Forests Guideline
1994 – Generic Environmental Impact Statement on Timber Harvesting and Forest Management in Minnesota was published
1994 – The DNR forms the Old Growth Forest Committee made up of representatives from the divisions of Forestry, Wildlife, Parks and Recreation, and Ecological Services along with representatives from the Commissioner’s Office and Office of Management and Budget Services. The committee established a round table of forest industry and environmental stakeholders and agreed on targets for protecting the remaining high-quality old growth forests on state lands. Old growth guidelines developed.
1998 – The old growth guideline is implemented with a systematic inventory, evaluation, and designation using an old growth database
2003 – Old growth forest designation of highest quality forests completed (with exception of lowland conifer forests)
2015 – DNR Commissioner approves the stakeholder-reviewed criteria to identify and evaluate lowland conifer old growth.
Currently – The DNR continues to manage old growth forests and is working on completing a designation process for lowland conifer old growth forests.