Fact Sheets

Invasive Species in US Forests: Risks and Information Needs

Invasive species are non-native organisms that can cause significant negative economic and/or ecological effects across large landscapes. Invasive plants can reduce forest productivity, inhibit regeneration, and increase fire risk; invasive insects and pathogens can damage and kill trees. Over the past 200 years, hundreds of invasive species have become established in the United States, with estimated damages exceeding $150 million per year in the forest sector. Previous invasions have functionally eliminated a keystone species in eastern North American forests, the American chestnut (Castanea dentata), and currently threaten to eliminate ash (Fraxinus spp.), redbay (Persea borbonia), eastern hemlock (Tsuga canadensis), and other tree species. The rate of spread of invasive species has increased over the past several decades due to growth in international trade and transportation.

This fact sheet provides a brief overview of the risks to commercial forestry posed by invasive species, and the current research gaps associated with cost-effective solutions.