|Black Willow – Salix nigra
Family Salicaceae – Willow, Cottonwood, Aspen.
Black willow is the largest and the only commercially important willow of about 90 species native to North America.
|Commonly called Gooding willow, Dudley willow, swamp willow, and sauz, black willow is the largest and the only commercially important willow of about 90 species native to North America. It is more distinctly a tree throughout its range than any other native willow; 27 species attain tree size in only part of their range. Other names sometimes used are swamp willow, Goodding willow, southwestern black willow, Dudley willow, and sauz (Spanish). This short-lived, fast-growing tree reaches its maximum size and development in the lower Mississippi River Valley and bottom lands of the Gulf Coastal Plain. Stringent requirements of seed germination and seedling establishment limit black willow to wet soils near water courses, especially floodplains, where it often grows in pure stands. Black willow is used for a variety of wooden products and the tree, with its dense root system, is excellent for stabilizing eroding lands.
Black willow is found throughout the Eastern United States and adjacent parts of Canada and Mexico. The range extends from southern New Brunswick and central Maine west in Quebec, southern Ontario, and central Michigan to southeastern Minnesota; south and west to the Rio Grande just below its confluence with the Pecos River; and east along the gulf coast, through the Florida panhandle and southern Georgia. Some authorities consider Salix gooddingii as a variety of S. nigra, which extends the range to the Western United States.
Rooting Habit- Willow tends to be shallow rooted, especially on clay-capped alluvial soils. It is seldom found on soil types that undergo seasonal dehydration but is more often present on soils with higher water tables throughout the summer months. Floods may deposit more layers of alluvium in established stands. New roots often develop from adventitious buds formed within the previously exposed trunk. By this means, soil is captured and held to form additional land areas along river courses. Willows also sucker readily. Under certain conditions, an essentially pure willow stand of 1 or more hectares (2.5 acres) may consist of relatively few clones.
Reaction to Competition- Black willow is less tolerant of shade than any of its associates and may most accurately be classed as very intolerant. It usually grows in dense, even-aged stands, in which natural mortality is very heavy from sapling stage to maturity. Trees fail to assert dominance, so willow stands periodically stagnate. Stands not properly thinned may lose up to 50 percent of their volume in 5 to 8 years. Because of its intolerance and the absence of exposed mineral soil under existing stands, willow does not succeed itself naturally unless fresh sediment is deposited as the stand begins to open up. Thinning should remove the understory trees and must be light to prevent the heavy windthrow and stem breakage, which is common in very open stands.
Damaging Agents– Several insects attack willow but few cause serious damage. The forest tent caterpillar (Malacosoma disstria), the gypsy moth (Lymantria dispar), the cottonwood leaf beetle (Chrysomela scripta), the willow sawfly (Nematus ventralis), and the imported willow leaf beetle (Plagiodera versicolora) sometimes partially, occasionally completely, defoliate willow trees, reducing growth but seldom killing. Stem borers, such as the cottonwood borer (Plectrodera scalator) attack willows and may kill by girdling the base. Twig borers, like the willow-branch borer (Oberea ferruginea), feed on the branches and cause deformities that may be undesirable in ornamentals.
Insects are frequently the vectors for disease organisms. Willow blight, the scab and black canker caused by Pollaccia saliciperda, is transmitted by borers. Members of the genus Salix are the only known hosts. Phytophthora cactorum causes bleeding canker, lesions on the lower trunk that discharge a dark-colored, often slimy liquid. Confined to the phloem and cambium area, it can result in death if the canker girdles the trunk. Cytospora chrysosperma causes canker in poplar and willow.
The wood is light (specific gravity 0.34 to 0.41), usually straight grained, without characteristic odor or taste, weak in bending, compression, and moderately high in shock resistance. It works well with tools, glues well, and stains and finishes well but is very low in durability. The wood was once used extensively for artificial limbs, because it is lightweight, doesn't splinter easily, and holds its shape well. It is still used for boxes and crates, furniture core stock, turned pieces, table tops, slack cooperage, wooden novelties, charcoal, and pulp.
Ancient pharmacopoeia recognized the bark and leaves of willow as useful in the treatment of rheumatism. In 1829, the natural glucoside salicin was isolated from willow. Today it is the basic ingredient of aspirin, although salicyclic acid is synthesized rather than extracted from its natural state. — from the USDA Forest Service
1. USDA NRCS Plant Materials Program,"Black Willow"
2. NATIONAL AUDUBON SOCIETY, National Audubon Society Field Guide to North American Trees
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Family Salicaceae — Willow, Cottonwood, Aspen
There are only two genera in this family, Salix (willows), with about 300 species, and Populus (poplars), with barely 40 species. Salicaceae are found throughout the temperate parts of the world, with the majority of species occurring in the north; both willows and poplars have a strong affinity for water.
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