Forest Invaders

Plants and animals that are not native to an ecosystem and are likely to cause economic or environmental harm are considered invasive species. These invaders are significant threats to healthy forests in Minnesota and throughout the nation. Prevention, as well as early detection and rapid response, are the first line of defense against new introductions. Once an invasive species becomes established, controlling it and restoring native vegetation is often a slow and costly process.

Invasive species arrive in Minnesota forests by various means—hitch-hiking on vehicles and equipment, stowed away in firewood and wood packing material, or creeping, crawling, and blowing with the wind. Once established in the forest, the invaders crowd out and prey upon native species, altering habitat and disrupting natural ecosystems.

Some invasive species destroy desirable trees and forest vegetation. Since its discovery in Michigan in 2002, the emerald ash borer has killed over 20 million trees in Michigan, Indiana, and Ohio. Although not yet found in Minnesota, forestry officials say this Asian pest poses a serious threat to the state’s ash trees. Other invaders, such as buckthorn, are established in Minnesota forests and are difficult to control and eradicate.

As a private forest landowner, you can help prevent the spread of invasive species. Use this guide to identify invasive plants growing on your property and take immediate steps to control and manage them. Early detection of invasive insects and plants is key to effective control. If you suspect these or other invasive species are present on your land, contact the Minnesota Department of Agriculture, a local state forestry office or your county extension agent. They can identify the pest and recommend control measures. You may also refer to the websites listed on the back page of this publication. Vigilance and a rapid response to the discovery of invasive species are the best ways to protect your forest investment.

The goal of the Sustainable Forestry Initiative (SFI) is to ensure future generations enjoy the same opportunities provided by the abundant forests we enjoy today. Meeting the challenges of invasive species prevention, control, and management are necessary to achieve that goal. This manual gives you an overview of some invasive species threatening Minnesota forests and introduces responsible forest practices you can use to manage invasive species on your land. A healthy, sustainable forest provides the greatest benefits and opportunities to you, the landowner.

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