What is a Woodland?

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A woodland is a habitat where trees are the dominant plant form. The individual tree canopies generally overlap and interlink, often forming a more or less continuous canopy which shades the ground to varying degrees.

However, woodlands are not just trees!

Depending on the amount of light reaching the ground through the tree canopy, there will be a great variety of other plants. These will include mosses, ferns and lichens, as well as small flowering herbs, grasses and shrubs. The more different kinds of plants there are, the greater the animal diversity will be in the woodland. This will range from a variety of herbivores feeding on the different plants, to the carnivores which they provide food for. Plenty of rotting wood and decaying leaf litter offer an alternative food source for a staggering variety of invertebrates. The sheer quantity of dead organic material present means that a wealth of decomposing organisms, such as fungi and bacteria also occur in woods.

A woodland which is planted, rather than having arisen naturally, is termed a plantation. Plantations managed for timber production (forestry) are sometimes called 'forests' in common usage. In England, the term 'Forest' (capital F) refers to an area where the King/Queen has the right to keep deer and to make Forest Laws.

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Woodlands vary greatly depending on the dominant tree species making up the wood, as well as on the spacing between individual trees. These two factors will determine the amount of light penetrating through the main leaf canopy and reaching the woodland floor. The more light available beneath the trees, the greater the number of other plant species which will also be able to grow within the woodland.

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Different tree species have leaf canopies which vary in their density and thickness. If you look at the ground beneath a tall, mature Beech tree, you will usually find a large ring of bare ground where little is growing. This is a result of the dense shade cast by the tree's thick canopy of leaves (left). In contrast, Ash trees, which have finely divided *compound leaves and a much less dense canopy, will permit the growth of a greater variety of plants beneath them.

*Compound leaves are leaves which are made up of a number of different leaflets.

In woodlands, tree spacing is determined naturally as a result of competition between individual tree seedlings for necessities such as space, light, nutrients and water. In plantations, the spacing will be determined by how close together the trees were originally planted and whether any of the intermediate trees have been cut down (thinned). Plantations of young coniferous trees prior to thinning are often very dark places. This is because the trees are planted close together to discourage the growth of other competing plant species.

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Plants growing on and under the trees in a woodland can include a surprising number of different mosses and lichens. For example, around 80 different species of moss might be found growing within an Oak woodland. The number of different kinds of lichen in a woodland may far surpass this, with up to 300 different species per km2 recorded in areas such as the New Forest. Oak trees alone can support up to 324 different species of lichen!

The mosses and lichens will all provide microhabitats for a range of invertebrates.

. .
wpe89.jpg (26729 bytes) You might occasionally notice trees which look astonishingly as if they have been painted with bright orange paint all up one side. This effect is created by the presence of great masses of  a very simple type of plant called an alga. This particular alga (Trentepohlia spp.) is comprised of filaments of cells containing high concentrations of carotene, which imparts the vivid orange colour. The sheer density of algae on the tree trunk creates the painted effect. The algae are often found on the north side of trees. This is because they are susceptible to desiccation and are more likely to dry out and die in prolonged direct sunlight. A similar effect may also occur with green-coloured algae. wpe8A.jpg (16904 bytes)

If there is sufficient light penetrating to the woodland floor, it is likely that there will also be a variety of ferns and grasses, together with wonderful carpets of herbs such as spring-flowering Bluebells, Wood Anemones, Primroses and Violets.

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Bluebell Wood Anemone Primrose Violet