What makes one type or species of tree look different from another? What are the clues which help us distinguish them?
A number of basic points help to tell you which tree is which. Most good identification books will provide key points on all the characteristics described below. Some of the characteristics are dependent upon the time of year.
- Size and shape: some trees are typically short and squat, others are tall and thin with all sorts of shapes and sizes in between
- Leaves: the leaf shape, size and colour are all important characteristics in identification
- Flowers, fruit or cones: these can also be useful identification points but may only be found at certain times of the year
- Trunks: tree trunk or bark can become familiar to you with practice; each has typical colour, pattern and texture.
- Winter twigs and buds: identifying deciduous trees in the winter can be tricky but twigs and buds are usually quite distinctive, their size, shape, colour and layout along the twig are all good indicators
Establishing whether the tree you are observing is broad-leaved or coniferous can be a good start to identification.
- Most broad-leaved trees are deciduous and shed their leaves in winter.
- The leaves of conifers are either needle-like or small and scale-like and normally present all year.
As always, there are exceptions to the rule; for example, holly is an evergreen broadleaf and larch is a deciduous conifer.
You can use the same characteristics as those listed above to identify conifers, but instead of examining leaves you will be comparing the number and structure of the needles and also considering colour and scent.
It is always worth remembering that individual trees are quite adaptable or ‘plastic’. You may find two trees of the same species that look quite different. Some of this variation is due to the immediate environment surrounding the tree. For example, an oak that has grown on its own out in an open field may look quite different from one that has grown up squashed between other trees in a woodland situation.
The shade and sun leaves of a Horse Chestnut tree
The leaves also vary enormously even on the same tree. This is because a tree makes its leaves according to how much light is available and typically produces ‘sun leaves’ and ‘shade leaves’. Sun leaves tend to be near the top of the tree and have the most exposure to light. They are smaller in size and have less chlorophyll, making them lighter in colour and able to tolerate bright light without wilting. Shade leaves are those situated in the parts of the tree that receives less light, such as the lower branches. Shade leaves are larger and contain more chlorophyll, making them darker in colour; this helps them absorb what little light is available to them.