A walk took place on 3rd May 2010 with members of the public to show those present which species of trees grow here and how to identify them.
The resulting data are considerable and not easy to adapt to a website so that they can all be printed off for anyone wanting to walk round. We are trying the approach of having:-
- Three short walks of roughly twelve trees, each of which can be downloaded and printed on three sheets of A4.
- A list of most trees with a map, which will form a catalogue (not printable).
Identification of trees is not always easy. As you may know, botanists name organisms by the name of the genus, or close-family name, followed by the name of the species. The generic name is given a capital letter, thus Betula pubescens (downy birch). It is mostly fairly simple to decide on the genus, such as for example Salix in the case of willows, Cupressus for cypresses, Betula for birches and Quercus for oaks. Reaching the correct specific name is not so easy. Some are very alike and need a lens, for example the cypresses. Some hybridize easily, and these develop characters intermediate between the parents. This is true for willows, birches and oaks. Perhaps identifying the genus is enough for most purposes. The advantage of the botanical method of naming organisms is that their relationships become clear.
Trees are identified using a number of characters. It is as if we see trees through various windows or dimensions. Botanists work mainly using the reproductive organs, the flowers, and fruit or cones. But these are not always present or may be out of reach. Some parts may usefully have fallen to the ground. The foliage of Magnolias is often very similar between species, and flowers are really needed, especially as much breeding has taken place to produce different beautiful flowers. Leaves are only present for part of the year in broadleaved trees or hardwoods. Conifers are generally evergreen, except the larches which lose their leaves for the winter. Twigs and buds may be distinctive, as may the bark. The form of the tree may help: is it tall, single stemmed from the base, or a low shrub with a number of stems from the ground? The English elm grows tall with rounded crowns, and large branches may drop (on the riverbank opposite the flats at Woodhall Millbrae). The elms in Ravelston Dykes are the Dawyk variety, pyramid-shaped with small safer branches. Many of our trees grow in gardens, so their growth is often constrained.
Some trees shout their identification at you, for example the ground around a Whitebeam in the winter is often covered with reddish-purple leaves, mixed with white where they have fallen face down and the hairy backs are showing. If the ground round large trees is nearly ankle-deep in white cotton, they are poplars. If low shrubs are covered with white silk, this is almost certainly an attack by the ermine moth on the goat willow (you may have seen this on TV in 2010). Cherries clearly announce their identification for a short period in spring when in bloom. And there are the autumn colours.
There are native British species, but we have imported species from all over the world, which does not make the task of identification easier. Having been trained originally for commercial forestry, I tend to look for the exotic species foresters have found successful over the years such as Douglas fir, Sitka spruce and contorta pine, but this is often not much help in identifying those in gardens. Conservationists often frown on the early successful introductions, such as sycamore and beech.
Trees shown on the general map of Juniper Green and Baberton Mains are numbered according to the species list. These are where representative specimens of each can be seen. For some, several locations are shown. Others are very common, such as sycamores along the Water of Leith path, and lilacs in gardens. I have given a short description of each species, and in most cases a photograph of characteristic foliage or other parts.
Classification: Botanically higher plants are divided into Gymnosperms or those which reproduce by cones (the conifers), except the yew tree, and Angiosperms or flowering plants. These are again divided into Dicotyledons, which include most flowering plants and deciduous or hardwood trees, and Monocotyledons which include the grasses and the palm tree.
Conifers have needle-shaped leaves, or scale leaves in the cypresses and Wellingtonia. They are all evergreen except for the larch (there always seems to be an exception).
Leaves of hardwoods are mostly deciduous, but again there are exceptions in the laurel and Portuguese laurel. Leaves provide the best means of identification, but when they are not present other characters must be used. Due to considerations of space, I have not repeated descriptions of leaves in words. Some, such as Prunus “Kanzan” have a reddish stalk.
Don’t be put off by the large number of simple roughly-oval leaves. Their surface texture and colour differ. Also you will soon associate each with the size and shape of the tree, the bark, buds, flowers and fruit. It is a good idea on a tree walk to give this a little time.
Leaves may be simple or compound (consisting of a standard arrangement of leaflets). Their margins may be linear, toothed or lobed.
Identification notes are given next to each listed species. The photographs of most leaves or foliage are not on the same scale.
On the General List the first number for each leaf photograph is the species number. The second number is the typical length of the leaf blade (cm) or leaflet in the case of a compound leaf. For the tree walks, only the length is given.
Clearly a second walk can follow the first taken, according to the time available. Each walk has at least one species not found elsewhere.
Tree Walk 1 - With thirteen tree species, proceed northeast along the Lanark Road from the Old Post Office opposite the Royal Bank of Scotland, to Gillespie Crossroads. There is an interesting variety of trees in the gardens, but you can only handle the foliage of a few.
Tree Walk 2 in Curriemuirend Park is quite different. You can handle the foliage easily because the trees are small and the foliage has not grown out of reach. The trees were planted in 2000 with Millennium money and consist largely of Scots pine and silver birch with other interesting species.
Tree Walk 3 – Starting at the top of Dr Mackay’s Wood, walking down, and back to the Old Post Office along the Water of Leith. This wood was planted mainly in 2005 by the old Juniper Green Village Association, after the ground was given to the City by Dr Mackay, and provides an opportunity to compare the two native cherries.
Please let me know if I have missed something interesting, if you spot an error, or whether you would prefer the data be in a different form. At: email@example.com.
Eric White - 3 May 2011