What+is+Happening+to+Forest+Communities

Currently, about one third of the nation's land area is forested. Forests provide us with numerous economic, social, and environmental benefits. While disturbance is a normal aspect of a functioning ecosystem, excessive disturbance caused by overuse and abuse can result in forest health problems, including invasion by nonnative pests such as insects, diseases, and invasive plants. In forests, invasive plants reduce habitat for native and endangered species, degrade riparian areas, create fire hazards, and interfere with recreational activities.Forest communities may also be altered by weeds. For example, the invasion of St. John's wort into "partial cut" stands in the Umatilla National Forest near Looking Glass Fish Hatchery in Oregon has been observed. This weed is displacing native species that are important for soil nutrient development, soil microbial development, and water cycling. Mildly poisonous, St. John's wort may also affect certain species of wildlife (Harrod et al. 1996).
 * =What is Happening to Forest Communities=


 * FACT: Invasive plants cause fire hazards.** Weeds such as cheatgrass increase fuel loads and can create fire hazards around electrical substations and areas where flammable products such as lumber and oil products are stored.


 * FACT: Invasive plants are a serious problem in forest nurseries.** In infested clearcut areas and forest nurseries, introduced vines such as kudzu and mile-a-minute quickly cover the ground and can prevent the growth of seedling trees.


 * FACT: Invasive plants affect young pine plantations.** The importance of weed control in forestry enterprises is illustrated in young pine plantations. In studies conducted in Georgia and Louisiana, pine yields were 63% greater on sites where weeds were controlled than on sites where weeds were not controlled. Arkansas foresters have concluded that the cost of weed management in their pine plantations could exceed $12 million annually (Yeiser 1 988).


 * FACT: Invasive plants affect forest health.** Healthy forests have a relatively open understory and permit sunlight to filter through the tree cover to the forest floor where resident animals and low lying plants can benefit from the heat and light. When invaded by an aggressive nonnative plant, the forest understory becomes a monoculture that crowds out the native plants and animals. Once established in a forest, invasive plants also increase the effects of natural disturbances (e.g., fire, flooding, and drought) (Brian Bowen, Tennessee Exotic Pest Plant Council, personal communication, 1996).

=Invasive Plant Primers= Mile-a-minute was first collected in the United States from ship ballast near Portland, Oregon, in the 1890s. The plant next appeared in rhododendron nurseries in York County, Pennsylvania, in 1946. Since that time, mile-a-minute has spread to New York, West Virginia, Maryland, Delaware, the District of Columbia, and Virginia. It has also been collected in Mississippi. Since its first appearance in Pennsylvania in the 1940s, mile-a-minute has been spread by birds and rodents and carried in rivers and streams. A very invasive plant, mile-a-minute outcompetes much of the native flora. Under favorable growing conditions, the plant will spread rapidly and reach high densities in locally abundant populations. Mile-a-minute occupies a niche similar to Japanese honeysuckle. It is an excellent climber and can spread easily over shrubs and understory trees (Mountain 1989).
 * Mile-a-minute**//Polygonum perfoliatum L.//A prickly annual vine from Asia, mile-a-minute grows up to 20 feet long. Mile-a-minute has pale green triangular shaped leaves and blue berrylike fruit. A population of the plant climbing over other plants and structures will appear to be light green compared to most surrounding vegetation. Dead plants turn reddish brown in winter. Typical habitats are roadsides (especially sites planted with crown vetch), forest and thicket margins, nurseries, reforestation clear-cuts, utility rights-of-way, low meadows and stream banks, orchards, and nurseries.
 * Introduction andSpread of Mile-a-minute**.

=Kudzu= //Pueraria montana var. Iobata (Willd.) Maesen & S. Almeida//A high-climbing perennial vine from eastern Asia, kudzu has alternate leaves and deep purple, pealike flowers. The brown, fuzzy fruit pod is 1 to 2 inches long with small rounded seeds. Although the vines are killed each year by frost, the deep fleshy roots survive the mild winters of the South and resprout with vigor each spring. Kudzu is abundant throughout the southeastern United States from Texas to Virginia and southward. Kudzu grows on roadsides and railroad embankments, in vacant lots, in timberlands, and in fields.**Introduction and Spread of Kudzu**. At one time, the federal government paid as much as $8 per acre for farmers to plant kudzu. Kudzu clubs were formed to promote its use, including the 20,000 member Kudzu Club of America. Channing Cope, the founder of the club, christened kudzu the "miracle vine." Soon communities were holding kudzu festivals and crowning kudzu queens.
 * 1876.** The Japanese government first exhibited kudzu as an ornamental vine at the Philadelphia Centennial Exposition in 1876. Soon afterwards, kudzu became valued for the fragrant purple flowers and the large hairy leaves that provide dense shade for an arbor or a screen for a fence. Later, kudzu was grown in the southern United States as a forage crop, to reduce erosion, and to improve the soil.1935. The Soil Conservation Service began using kudzu as a soil binder to prevent soil erosion on road cuts and farmlands.


 * 1946.** Kudzu had been established on 3,000,000 acres of highly erodible land across the South (Williams 1994; Bell and Wilson 1989).


 * 1955.** The plant had escaped its original plantings and covered power poles, trees, shrubs, gardens, fences, and anything else that stood in its path. Kudzu's ability to grow as much as a foot per day during the summer months eventually earned it the name "the vine that ate the South." Kudzu was listed as a common weed by the U.S. Department of Agriculture in 1970 (Agricultural Research Service 1971).


 * 1998.** Today, kudzu is widespread throughout the Southeast and covers large areas with impenetrable thickets. The plant poses a serious threat to timberland, because the dense foliage totally blocks out sunlight. Over 7 million acres are estimated to be infested (Jim Miller, U.S. Forest Service, Auburn, Alabama, personal communication, 1996). ||