Assessing the Health of U.S. Forests

Forests are complex ecosystems. They are constantly changing as a result of tree growth, variations in weather and climate, and disturbances from fire, pathogens, and other stressors. The USDA Forest Service Forest Health Monitoring (FHM) program tracks these ongoing changes — every year, across the nation — as a forest health check up. The 2018…  More 

The Thorny Economics of Preventing Exotic Species Introductions

What if we lose tree species we know, love, and need? It has happened before. “Look at what happened to the American chestnut,” says U.S. Forest Service research forester Thomas Holmes. “Look at what’s happening right now to hemlock, redbay, and ash trees.” All three species, as well as many more, are threatened by non-native…  More 

Plant Invasion Patterns at Global and Regional Scales

From the moment of colonization, humans have carried non-native plants around the world with them. “The introductions are changing the world’s biogeography,” says U.S. Forest Service research ecologist Qinfeng Guo. “Understanding the mechanisms behind invasion patterns is critically important.” Invasion patterns vary depending on the scale. At finer scales, invasions are often related to competition.…  More 

Exotic Plants May Dominate After a Fire, But Not for Long

Land managers expect that exotic invasive plants will quickly move in following a disturbance, especially after a fire. Though exotics initially might have an edge over native plants on burned ground, this may not always be so as time goes on, according to a U.S. Forest Service study. Qinfeng Guo, a research ecologist with the…  More 

Cogongrass Continues to Invade the South

It grows on every continent except Antarctica and has earned a reputation as one of the worst weeds on earth — and according to U.S. Forest Service emeritus scientist Jim Miller, cogongrass (Imperata cylindrica) is without doubt one of the most threatening invasive species in the South. In addition to cogongrass, it goes by  other…  More 

Native Trees Naturally Fight Invasives in Some Eastern Forests

In this modern society, non-stop movement of people and goods means that invasive species will continue to move and spread, too. Recent research indicates that invasive plants can be found in nearly half of the forests of the eastern United States, raising concerns about the sustainability of these ecosystems and the benefits and services they…  More