Branching Out – Hedgerow Heroes

With Dr Isabella Brey

Small and unassuming, field maples often go unnoticed for most of the year, dutifully playing their role in the lives of the many species that depend on them and their hedge-row and woodland-edge habitat for survival. The cheerful little trees become hard to overlook, however, when they end their growing season with a flourish by adding bright splashes of radiant yellow to the otherwise solemn late autumn landscape.

The field maple (Acer campestris) is the only maple species native to Britain, yet it remains the least familiar. It is a small and relatively slow-growing tree, which means it is of little interest to the timber industry and so is rarely planted for commercial reasons. Nevertheless, field maple wood is held in high esteem by artisans because it possesses great strength and elasticity while being easily worked. In the past it was used for a multitude of small everyday utensils that had to be strong and durable, such as chopping boards, rolling pins and tool handles, and it is occasionally still used for such purposes today. The wood is so strong that even shoemaker’s nails were made from it. Nowadays, field maple wood is mainly used for making musical instruments and tobacco pipes, for wood turning and carving and sometimes for veneers.

Mature field maple trees lucky enough to have been allowed to grow and develop naturally in a favourable location often take on a distinctive shape, appearing to possess several trunks (photo 1). This interesting feature is particularly obvious during the winter months (photo 2).

At this time of year other structural characteristics also show up more clearly, for example the much-branched overall appearance, particularly the large numbers of heavily branched twigs near the ends of the branches, as well as the slight droop of the branches before they curve upwards again at the tips.

Field maples can live to 300 years, but even the oldest specimens rarely exceed 20 metres in height. Tall, free-standing, mature field maples are relatively rare. Much more often they take on more irregular shapes as they eke out a living partially overshadowed by taller trees in woodland edge habitats, where they are easily spotted during late autumn when they sport their characteristic bright yellow autumn colours, retaining their leaves much longer than most other trees (photo 3).

Even more frequently, field maples establish themselves in hedgerows and take on a shrubby habit. They are very tolerant of pruning and are able to re-shoot even after being cut back to a stump. Field maples require increasing amounts of light as they mature, so they do not do well in the presence of taller trees and are only occasionally found as part of mixed woodlands.

Within a hedgerow, winter identification of field maples can turn out to be surprisingly easy if one happens to spot the unusual and distinctive corky bark that forms on some of the young twigs and stems (photo 4). The buds are greenish to reddish-brown and grow in opposite pairs. On twigs which have fruited, two buds form very close together on either side of the stem of the fruit (which then drops off during the winter) (photo 5). Such twigs go on to branch from this point during the following season.

Field maples flower in April, at the same time as the leaves start to unfold (photo 6). The insect-pollinated flowers (photos 7 & 8) possess both male and female parts, but one is usually more strongly developed than the other. The paired winged fruits are easy to distinguish from those of the related sycamore and Norway maple because they are virtually straight (photo 9), whereas those of the latter species form more or less acute ‘V’ shapes.

 

Field maple leaves, too, are easily recognized. They are much smaller, generally more deeply lobed, and more rounded than those of sycamore and Norway maple (photo 10). They also possess a waxy coating, which makes field maples much more resistant to water loss in periods of drought than their relatives. This characteristic allows field maples to compete very successfully in the more southerly areas of their range, which encompasses most of Europe. They are only absent from the most climatically challenging locations in the far north and south as well as the alpine regions. Field maples have also become successfully established as introduced species in many other parts of the world.

Field maple leaves make good forage for a variety of animals and used to be a popular livestock feed. Not all species feeding on field maple leaves are large and familiar, however. A number of minute leaf-mining insects and gall-forming mites as well as certain fungi also depend on them, for example the leaf-mining micro-moths of the genus Stigmella and the fungus Didymosporina aceris (a mine of the former and the leaf-spots caused by the latter are both visible in photo 10).

Several more insect species develop on field maple buds or the developing fruits. Birds and small mammals feed on the seeds in autumn, and field maples are popular nesting sites for birds as well as providing them with sheltered roosts in the winter because they retain their leaves so much longer than most other trees. Field maple bark is a favoured substrate for the establishment of epiphytic mosses and lichens, and old trunks can become hosts to rich, and very attractive, epiphytic assemblages (photo 11).

Their ecological value, small size, tolerance of pruning and showy autumn colours make field maples popular for horticultural use, and a number of cultivars with various growing habits and foliage colours are available. Their high resistance to pollution also makes field maples suitable for inclusion in urban planting schemes, where the combination of their aforementioned characteristics really makes them come into their own. As a result, these delightful trees are just as likely to brighten one’s day in the heart of a metropolis as they are in the midst of a rural hedgerow far removed from the madding crowd.

 

 

 

 

 

 

 

 

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