Trees & Shrubs – The Maple – Acers
Acer /ˈeɪsər/ is a genus of trees or shrubs commonly known as maple. Maples are variously classified in a family of their own, the Aceraceae, or together with the Hippocastanaceae included in the family Sapindaceae. Modern classifications, including the Angiosperm Phylogeny Group system, favour inclusion in Sapindaceae.
In London we mainly see the native Acer campestre Field maple: (details below) and the common London tree the Sycamore Acer pseudoplatanus (sycamore maple).
There are approximately 128 species, most of which are native to Asia, with a number also appearing in Europe, northern Africa, and North America. Only one species, the poorly studied Acer laurinum, is native to the Southern Hemisphere. Fifty-four species of maples meet the International Union for Conservation of Nature criteria for being under threat of extinction in their native habitat.
Some species of maple are extensively planted as ornamental trees by homeowners, businesses and municipalities due to their relatively fast growth, ease of transplanting, and lack of hard seeds that would pose a problem for mowing lawns. Particularly popular are Norway Maple, Silver Maple, Japanese Maple, and Red Maple. Other maples, especially smaller or more unusual species, are popular as specimen trees.
The Norway Maple (Acer platanoides) is a tree of much more recent (1683) introduction from the Continent. Its height is from thirty to sixty feet, and its early growth is very rapid. The leaves are even larger than those of Sycamore, of similar shape, but the lobes are only slightly toothed. The clusters of bright yellow flowers are almost erect; the tree does not produce seed until it is between forty and fifty years old.
Field Maple -Acer Campestre
A top 5 recommended native tree for gardens by the RHS.
The Maple (Acer campestre).
There are a number of Maples in cultivation, but only three of them are commonly met with in the open, and of these one alone is a native. This is the Small-leaved, Common, or Field Maple (Acer campestre), a small tree that attains a height of twenty or thirty feet in the tall hedgerow or in the wood, but is most familiar as a mere bush or as a constituent of the low field-hedge. It does not grow to any considerable thickness of bole, so has no importance as timber, but the turner, the cabinet-maker, and the artist in fancy pipes and snuff-boxes, are glad to make use of its fine-grained, pale-brown wood. This is often beautifully veined, especially the wood from the roots, and as it will take a high polish, which brings out these markings plainly, it is a very desirable wood for such purposes. The brown bark gives little clue to the character of the wood it covers, for in young trees it is rough and deeply fissured, though with age it becomes smooth.
The leaves vary greatly in size, those growing on a tree being much larger than those produced by a bush. They range from two to four inches in diameter, and are always in pairs—springing from the sides of the branch exactly opposite to each other. The general form of the leaf is kidney-shaped, but it is cut up into five lobes, which are more or less toothed. They are downy when young, of a deep green colour, but too frequently this is disguised by a thick layer of road-dust. In October they turn to a rich yellow, and the Maple is then prominent even in a distant view, for the bright colour of the foliage makes the tree stand out prominently, in strong contrast with the still deep green of the Oaks or Firs beyond.
The Maples are among the trees that have complete flowers, although in this case they happen to be greenish yellow. They are about a quarter of an inch across, have narrow sepals and narrower petals, eight stamens, and a two-lobed flattened ovary, that develops into the pair of broad-winged “keys,” or samaras. These are individually much like those of the Ash, but unsymmetrical and curved, half an inch long, with their bases joined together. Sometimes in late summer these “keys” take on a colouring of deep crimson, previous to turning brown as they ripen. As a rule the contained seeds take eighteen months to germinate, though a few may start growth the first spring.
The Common Maple is thought to be indigenous only from the county of Durham to the southern coast, and in Ireland. In Scotland it is only an introduced plant that has become naturalized.