Many people can easily identify trees that are common in the area in which they live. However, there are times, for example when travelling or when confronted with an unfamiliar species, that it is useful to be able to identify a tree in a more systematic way.
Reliable identification depends upon thorough observation. Gather as much information as possible in the form of notes, sketches, photographs and with permission, small samples of foliage including a flower and fruit, even if it is old material picked up from the ground. Another useful piece of equipment for fieldwork is a pair of binoculars to see features that are out of reach. Many types of binoculars work as a powerful hand lens if used backwards.
You will also find it useful to acquire a detailed guide to the trees in the area in which you are interested. Some guides known as keys are designed to identify trees by a process of elimination.
Trees are divided into groups according to certain distinguishing characters. Smaller groups are then sub divided, until finally the plant or group to which it belongs can be identified. It is important to always use a local key that refers to the region you are in.
Photographs and illustrations are a valuable aid at every stage of the identification process.
When faced with a tree that you are unable to identify immediately it is important to follow the process of identification systematically.
Observe and take notes on each aspect of the trees physical characteristics: bark, leaves, fruit and flowers. Take note too of the size of the tree and its habit (overall shape) although this is not necessarily a defining feature. Other important information to record could include the trees location and type of habitat in which it is growing for example, open parkland, barren mountainside, or dense forest. Note too, other tree species growing nearby.
Many tree enthusiasts derive great satisfaction from keeping their own log of interesting trees they have seen. Notes, photographs, sketches and bark rubbings can all contribute to a fascinating record of local trees. A record of associated birds, insects and other wildlife is also of interest. You might consider observing several trees in your area through the seasons and over a number of years.
Leaves – Observation should include taking note of its type, how it is arranged on the shoot, its overall shape, whether the leaf margins are smooth lobed or toothed and what colour they are above and beneath. Use a magnifying glass to observe fine hairs and veining.
Bark – The bark of a tree often changes with age. Nevertheless it is an important feature to observe. Note the colour and the texture; whether it is smooth, flaking or peeling or fissured. Make a bark rubbing with wax crayons for your records. You should also look for any resin visible from previous cuts in the bark. Do not make such cuts yourself.
Flowers – The colour and shape of the flower are the most obvious features but be sure to also look at their arrangement – whether they are solitary blooms or appear in a more complex group of flowers in a large ‘head’, ie elder. Some species have male and female flowers on the same tree. Others have male and female flowers on different trees.
Fruit – Fruit appear after flowers and will only rarely be seen together. They may be several different types. Take note of the external colour, shape and size. Then if possible, open one and observe the number and arrangements of seeds within the fruit. Be aware that fruit often changes significantly in size and colour as it ripens.
Taking Field Notes
When you go out tree spotting, you will find it helpful to take a few items of equipment to aid identification. You will need a notebook, pencil and a selection of coloured pencils to record your observations in words and pictures. You don’t need to be an accomplished artist to make useful visual notes and annotations. A magnifying glass will enable you to see details on leaves such as hairs and veins. With wax crayons and plain paper you can take rubbings of bark texture. If you intend to bring samples of fallen leaves or fruit home be sure to have a store of labels and bags to put them in. Lastly bring a camera to take photographs of the tree.
A tree dossier – detailed notes, sketches, bark rubbings, samples of leaves and fruit, should enable you to identify all but the most unusual trees.
Instead of drying up and becoming discoloured like leaves normally do, pressed leaves retain their shape and much of their colour. Collect newly fallen leaves. Place the leaves between two pieces of paper towel or blotting paper, making sure they do not overlap and lay them flat under a pile of books. Wait about a week for the leaves to dry completely before removing them. Instead of using books you can buy a specially made leaf press which is available at some craft stores. Not all leaves lend themselves to the procedure – leathery leaves like magnolia do not dry well.
To capture the patterns of bark, rub a crayon or graphite art stick over a thick piece of paper taped to the tree. The raised parts of the bark surface will leave corresponding marks on the paper. Record the name of the tree species on the sheet as well as the date and other information for future reference.
Leaf printing allows you to reproduce the beautiful symmetry of a leaf and its intricate network of veins in a style that resembles a wood cut. Green leaves with distinct veins such as maple and poplar provide the best results.
A more elaborate project than leaf pressing or bark rubbing, is leaf printing which requires two rubber hand rollers, printers ink and sheets of rice paper and plain paper. Your local craft store will probably carry these items.
Working on a sturdy surface, position the leaf – veined side up – on a sheet of plain paper, cover the inked side with a piece of rice paper and carefully tape the two pieces together. Run the clean roller back and forth across the top sheet pressing firmly. Peel the paper and leaf apart and let the print dry.
In most cases the best way to shoot a single tree is to turn your camera sideways for a vertical portrait shot that fills most of the frame. For a clear uncluttered shot, look for trees that stand alone and are set off by a simple background, such as the sky, that contrasts with the tree in colour or brightness. When possible, shoot from the same level as the tree angling the camera up or down will make the top or bottom of the tree look unnaturally narrow. If you must tilt the camera to capture the top of a tall tree, avoid using a very wide angle lens since this will exaggerate the distortion.
Lightly clouded days are best for photographing trees. Always keep the sun behind you. If you shoot early or late in the day, the lower angle of the sun will light the full height of the tree including the lower part of the trunk. Experiment with your camera’s backlight feature, f-stop, light meter and film types to get the best results. Film speeds of ASA 200 or lower yield pictures with more definition. And remember the higher the shutter speeds or a tripod can compensate for an unsteady hand.
Using a modern digital camera enables you to see the photograph immediately and allows you to keep taking photographs until you are satisfied.
Reproduced with permission of North West Parks Friends Forum