Types of Woodland
Woodlands can be divided into two main types, coniferous and broadleaf.
Within these two general categories are many other different types. These are usually
classified according to the dominant tree species making up the woodland.
Coniferous woodland, as its name suggests, is made
up predominantly of conifers. Conifers are trees often having needle-like leaves, such as
the familiar Christmas tree. They are usually evergreen. In other words, rather than
shedding their needles all at one time in the autumn, they lose a proportion throughout
the year, with these being constantly replaced. As a result, they always have foliage on
them. There are exceptions to this. For example, European Larch is deciduous, dropping all
of its needles in the autumn. All conifers also produce their seeds inside cones.
Broadleaf woodland is composed of trees with leaves
which are not needle-like. The leaves of different broadleaf trees come in all varieties
of shapes and sizes, but tend to be flat, broad shapes quite unlike the needles of
conifers. Most broadleaf trees in Britain are deciduous. This means that they lose all
their leaves in the autumn, remaining bare through the cold winter months until the
spring, when they grow new foliage. Some broadleaf trees however, are evergreen, rather
than deciduous. Holly is an example. The seeds of broadleaf trees are produced within a
great variety of different structures, from acorns to berries.
Coniferous and broadleaf trees are adapted to different climatic conditions. Conifers are
the dominant tree form in very cold climates, where snow and freezing conditions are the
norm in winter. The conical shape of the whole tree encourages snow
to fall off the branches rather than settling. This reduces the risk of large
accumulations of snow, which are very heavy and might cause branches to break under the
weight. Coniferous trees also have resins in their sap which vary with the species of
conifer. These act as a kind of antifreeze, preventing internal damage to cells by the
formation of sharp ice crystals.
you look at the bark of conifers such as Douglas Fir, or Grand Fir, you can see small
blisters all over the trunk. These are resin blisters and if you puncture one, the
resinous, sticky aromatic sap will seep out.
Broadleaf trees such as Oak and Beech are adapted to the cold, but somewhat milder winters
of temperate climates. Their spreading
shapes can accumulate large quantities of snow. Damage to branches in conditions of heavy
snowfall is thus a real possibility. This makes them less well adapted to really harsh
climatic conditions. Freezing damage to the cells is prevented by the autumnal loss of the
leaves, which are the most fragile unprotected tissues and the most likely to be damaged
by internal ice formation. The loss of the leaves and the cessation of photosynthesis,
means that water, minerals and nutrients no longer have to be transported to all parts of
the tree. Thus the sap no longer circulates and the trees essentially become dormant over
the winter period.
Continue to Woodland Structure