Seasonal Greening in U.S. Forests, Fields, and Urban Areas

Using the assessment tool ForWarn, land managers can monitor the growth and development of vegetation that signals winter’s end and the awakening of a new growing season. Researchers have devised a way to more precisely characterize the beginning of seasonal greening, or “greenup,” and compare its timing with that of the 14 previous years. Such information helps land managers anticipate and plan for the impacts of disturbances such as weather events and insect pests.

Three maps detailing greenup in …

What Are Invasive Species, and Why Should We Be Concerned About Them?

An invasive species is a nonnative species (in any reproductive stage, including seed, egg, spore, or other propagule) whose introduction causes or is likely to cause economic harm, environmental harm, or harm to human health. These species grow and reproduce rapidly, causing major disturbance to the areas in which they are present.

Yellow Starthistle
Steve Dewey, Utah State University, bugwood.org

The majority of nonnative species, including most of our sources of food and fiber, are not harmful, and many are highly beneficial. …