Balsam Woolly Adelgid in Fraser Fir

Written by: D. Moorhead and G.K. Douce for Forest Encyclopedia Network
Figure 1. Balsam woolly adelgid was first found on Mount Mitchell, North Carolina, in 1957. The Fraser fir trees located at high elevations on Mount Mitchell have experienced heavy mortality. Photo by Robert F. Billings, Texas Forest Service, courtesy of

The balsam woolly adelgid (Adelges piceae), a native of Europe, was first located in the southern Appalachians in 1957 on Mount Mitchell, North Carolina (Figure 1). …

Beech Bark Disease

Written by D. Kennard, D.J. Moorehead, C. Evans, and G.K. Douce for Forest Encyclopedia Network
Figure 1. Cankered stem of a beech tree following an attack by beech scale and infection by Nectria coccinea (beech bark disease complex) in Ontario. Photo by Linda Haugen, courtesy of

Beech bark disease (Fig. 1) is caused by a complex of two agents, the beech scale insect, Cryptococcus fagisuga (Fig. 2), and a fungus, Nectria coccinea faginata. Infestation is easily identified by …

Emerald Ash Borer

Written by: G.K. Douce, C. Evans, and D.J. Moorhead for Forest Encyclopedia Network
Figure 1. A map showing the spread of emerald ash borer within the northeastern United States and southeastern Canada.

Emerald ash borer, Agrilus planipennis, is a newly introduced species (found in 2002) from Asia. Populations have been found in Michigan, Ohio, Illinois, Indiana, Iowa, Maryland, Minnesota, Missouri, New York, Pennsylvania, Virginia, Wisconsin, Ontario, and Quebec (USDA 2011). Larvae feed on phloem and sapwood of ash …

Asian Longhorned Beetle

Written by D.J. Moorhead and G.K. Douce for Forest Encyclopedia Network

Asian longhorned beetle, Anoplophora glabripennis, is a recently introduced pest from China. It is believed to have entered the United States inside solid wood packing material from China (USDA – Forest Service 2002). It was first discovered in the United States in 1996 in New York. In 1998, an infestation was found in Chicago. In 2002, Asian longhorned beetle was found in New Jersey and has since spread …

Biodiversity in Forests

Written by Amy Grotta

Biodiversity refers to the range of life forms and species that exist within a given ecosystem. Different forest types have varying degrees of biodiversity. Tropical rain forests are some of the most biologically diverse ecosystems on the planet. However, even temperate forests consisting of only a few overstory tree species may contain surprising levels of biodiversity when all other life forms found within them are considered (e.g., herbaceous plants, mammals, birds, invertebrates, fungi, etc.).

Species exist …

Southern Pine Beetle

Written by G. K. Douce, C. Evans, and D. J. Moorhead for Forest Encyclopedia Network
Figure 1. Adult southern pine beetles. Photo by David T. Almquist, courtesy of

The adult southern pine beetle (SPB) is 2 to 4 millimeters in length, has a rounded abdomen, and is brownish-black in color (Figure 1). Males have a frontal groove on top of the head, while the females possess a broad elevated ridge called a mycangium on the anterior pronotum. Both males …

History of Southern Pine Beetle

Written by J.D. Ward and P. Mistretta for Forest Encyclopedia Network

The southern pine beetle (Dendroctonus frontalis Zimmermann) is a serious pest of pines in the southern United States, Mexico, and Central America. The southern pine beetle (SPB) kills pines by boring under the bark and destroying the cambium layer of the tree. Trees are often mass attacked by thousands of individual southern pine beetles. Because populations can build rapidly to outbreak levels, large numbers of trees can be …

Microflora and Fauna in Forests

Written by Peter Kolb, Montana State University

Forests (Figure 1) are composed of many trophic levels that include primary producers: large and dominant trees, as well as understory shrubs, forbs, grasses, mosses, lichens, and even algae; large and small herbivores such as moose, deer, mice, and caterpillars; carnivores such as cougars, coyotes, weasels, shrews, and cleride beetles; and decomposers, which could include larger animals such as bears that eat carrion but are usually comprised of smaller organisms such …

Insects in Forests

Written by Peter Kolb, Montana State University

Figure 1. Some common tree-inhabiting beetles including large staghorn beetles (center), roundheaded borers (left), and a variety of much smaller bark beetles (right). Photo courtesy of Peter Kolb, Montana State University.

Insects perform many roles within forests as pollinators, herbivores, carnivores, decomposers, and food sources for other organisms. As a group, they are the most abundant and important group in the phylum Arthropoda, and by 1972 more than 900,000 species had already been …