What is Ancient
Woodland? Ancient
woodland is designated as being land which has been continuously wooded since AD1600
in England and Wales, or AD1750 in Scotland. (The difference arises because of
the timing of available historical survey information.) These dates mark the beginning of
reasonably accurate historical information on local land use, often in the form of estate
maps. There are some records prior to this, notably the Domesday Book. This was an
amazingly detailed inventory for England, produced in 1086 and compiled on the orders of
the monarch of the time, King William. Some ancient woods are mentioned in the Domesday
Book. Other than this, there are unlikely to be reliable records to prove the existence of
individual woods prior to 1600.
It should be appreciated that while 300 - 400 years
seems suitably 'ancient' in human terms, it is a mere blink of an eye in Nature's time
scale. To put it in perspective, this is less than half the lifespan of a single large Oak
tree which may live for up to a thousand years!
Ancient Woodlands and
Biodiversity
Ancient woodlands are habitats which can have enormous biodiversity.
They may contain much of the same biodiversity present in more
recent woodlands. However, the great age of many of the trees and their resultant large
size, thick, cracked, fissured bark and rot-holes, all provide a great many additional
microhabitats for other species. The sheer age of the habitat itself and the absence of
major physical disturbance also gives rise to a continuum of conditions which favour a
variety of rarer species. In particular, this would include species which are either slow
to establish and, or which require very particular conditions in order to survive. This
means that ancient woodlands have potentially far greater biodiversity than more recently
established woodlands.
Individual old trees provide an amazing number of microhabitats for
other plants and animals. Many different kinds of weird and wonderful beetles and other
invertebrates may live in the cracks in gnarled and fissured old bark. Knotholes and
hollow centres in the heartwood of the tree, caused by wood-rotting fungi, can again
support a great variety of different types of invertebrates, as well as providing nesting
holes for birds and small mammals. Many of the invertebrates found in this type of
microhabitat have very specific requirements and are found nowhere else. For example, a
small black beetle, Dorcatoma ambjoerni, is a real specialist as it has been
found only inside hollow beeches, in the fruiting bodies of the bracket
fungus, Inonotus cuticularis.

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In areas where
air pollution is not a problem*, hundreds of different
species of lichens may clothe the branches of old trees in an ancient woodland. Lichens
often have very particular requirements for their establishment and growth and are very
slow-growing. Their diversity in ancient woodland is favoured by the great range of
different physical substrates provided by very old trees and also by the lack of physical
disturbance. This gives slow-growing species the opportunity to grow without sudden
changes in microclimate or removal of habitat. *Lichens
are very susceptible to air pollution. |
Ferns and mosses, which mostly require fairly damp
conditions, are common woodland plants. Different kinds of mosses grow on the woodland
floor, as well as on the bark of tree branches and trunks. Together with the lichens, they
provide another entirely different range of microhabitats for small invertebrates such as
mites and spiders. The presence of particular species of ferns, mosses and lichens can be
used to indicate ancient woodland status.
Where ancient woods have been coppiced
over the centuries, many plants other than trees will also abound. These will range from
small herbaceous plants, such as Wood Anemones, carpeting the woodland floor, to a variety
of shrubs and understorey trees. These might include Wild Service and Small-leaved Lime.
The reduced shading in coppiced areas allows a greater diversity of plants to flourish.
The practice of coppicing trees in rotation through the wood, rather than all at once,
meant that there were always suitable light conditions in some part of the wood. Even if
particular areas grew up and became shaded over, the underlying plants could survive by
colonizing other areas as they were coppiced.

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All
of the plants growing underneath the main tree canopy will in their turn have associated
animals. For example, the caterpillar of the Silver-washed Fritillary on
the left, feeds on violets |
Thick, springy layers of leaf litter underfoot,
accumulated over centuries, enrich and modify the underlying woodland soil. The leaf
litter will host innumerable invertebrates feeding on the leaf litter itself. In their
turn, they will provide food for mini-hunters of the woodland floor, such as centipedes
and spiders.
Hundreds of different types of fungi, largely invisible to the naked
eye except when fruiting, will infiltrate and decompose standing, or fallen, rotting tree
trunks and branches. Networks and mines of tunnels in the rotting wood may be inhabited by
some of the wide range of invertebrates in Britain which live in this microhabitat. The
only indication of their presence may be small entrance or exit holes, with no hint of the
labyrinths within.
Continue to Types
of Ancient Woodland
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