AgroForestryTree Database
Glossary W
water table
1. The upper edge of free water in the soil. When a hole is dug, water will fill the hole to the level of the water table.
2. The level below ground at which free water persists.
waterlogged
1. A condition of land where the groundwater stands at a level detrimental to plants. It may result from over irrigation, seepage or inadequate drainage.
2. Saturated with water. A soil condition with a high or a perched water table; detrimental to plant growth.
watershed, catchment basin, drainage basin
1. A physiographic unit in the landscape defined by the drainage dividers around the area drained by a particular body of water. If a lake, there is often one watershed with subunits for contributing streams. If a river, it may be defined for any point or all.
2. The total area, regardless of size, above a given point on a water-way that contributes runoff water to the flow at that point. A major drain-area subdivision of a drainage basin on the basis of this concept.
weed
A plant growing where it is not wanted.
weeding
The elimination of competing vegetation around young trees, for example, by cultivation, by the use of herbicides, or by cutting or slashing. When the trees are big enough to overcome weed competition, a tree plantation is said to be 'established'.
whorl
A ring or circle of plant organs arising close together, for example, leaves from a node, or a spiral of conifer branches from a main stem.
wilding
A young seedling that develops in the wild without the help of humans. This type of seedling is the best source of stock for some species.
wilt
Drooping of foliage from lack of water
windbreak See also windstrip
A group of trees or shrubs in any arrangement that will afford protection from high winds to animals or crops or both. When the arrangements are in a long line the group is called a shelterbelt. If an associated reason is also to harvest timber at some future date it is sometimes called a 'timberbelt'.
windstrip See also windbreak
A narrow plot of low vegetation (shrubs, bushes, herbs and grasses) left when natural vegetation is cleared so as to provide shelter to adjacent crops and to prevent wind erosion on sandy soils.
witches’ broom
The result of dense, prolific branching on a branch or stem, usually associated with a pathogen.
wood See also timber
1. Lignified secondarily thickened plant tissue. The structural parts of woody perennials.
2. A small grove of trees of mixed species complete with undergrowth. The size is variable but it does not cover a large area.
wooded grassland
Land covered with grasses and other herbaceous species, and with woody species that cover between approximately 10-40% of the ground.
woodland
An open stand of trees >8 metres high and with a canopy cover of 40% or more, usually among grasses. Woodland is often described by its dominant species, for example, 'Acacia woodland', 'Acacia themeda woodland', 'Combretum woodland'.
woodlot See also coppice, wood
A small plot of trees grown for fuelwood, which can also provide small timber and poles.
woody clump See also clumpwood
The aggregate of stems arising from woody organs at or below ground level; initiated from a single individual but sometimes separating to form a group of individual plants of the same genotype.
woody perennial
A plant with lignified stems that continues to grow from year to year.
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