CJS Focus on Trees and Hedges

Published: 21 November 2005

In Association with: Tree Council for National Tree Week

Trees and Biodiversity


The planting of trees is a vital part of the battle to protect and conserve our wildlife, whether it is the establishment or restoration of hedgerows, or planting new woodlands and forests.

With many of our woodlands grazed flat by livestock, and hedgerows flailed until they are just a row of sticks,  anyone who owns or rents a piece of land can help with conservation and increasing biodiversity.

Wildlife corridors are an important feature for species with limited mobility, such as dormice, as well as some species of bat which do not like to cross open areas. Linking areas of woodland with hedgerows can be as important as establishing additional, but isolated, woodland. A wildlife hedge should consist of a range of species, each native to the area and preferably of local provenance. Many wildlife hedges consist of 75-85% hawthorn, with additional species such as field maple, guelder rose, elder, oak, holly and hazel, but any mix of native species is good. Single species hedges such as beech and yew are best kept for more formal areas, as they provide a smaller range of food sources than a mixed hedge. Hedgerows can also be enhanced by planting climbers such as honeysuckle and wild roses. Plants can be either bare-rooted, planted during the dormant season, or cell-grown, but all should be cut back to about 150mm after planting, to encourage low-level growth. Therefore, small plants of 40-60cm or 60-90cm should be used. Planting a double row with about 5 plants per metre should give a nice thick hedge. Cutting of the hedge when it has reached the desired height and width should be timed to reduce the loss of flowers and fruit, and should not be done during the bird breeding season (March - September). A cut in the autumn will result in loss of fruits, so should be avoided. Similarly, cutting too late in the spring may result in loss of flowers. Therefore cutting is best undertaken during the winter, when all the fruit has been eaten, but before the end of dormancy. The hedge should be allowed to maintain a reasonable width, of at least 1.5m, to provide safe nesting places for birds and other animals. Alternatively, the hedge can be laid - this results in a very dense structure, and is an excellent way to restore an old neglected hedge.

Woodlands are very important to much of our wildlife, but many woods are species poor due to bad management. A healthy woodland should have many layers, including the ground flora, small and large shrubs, small trees, and the canopy trees. For example, a mature oak wood with an understorey of hazel, bramble and honeysuckle is excellent for many species, including the dormouse and, where it still survives, the red squirrel. Existing woodlands can often be enhanced by selective planting of missing or uncommon species, as well as selective felling and replanting if the age range of the trees is limited. Cut wood should be left within the wood to be recycled into the ecosystem. Planting new woodlands is an excellent way to increase the biodiversity and structural diversity of an area. Woodlands can be grown almost anywhere except the high mountain tops. Remember that most of our upland areas were once forested, and areas such as Cumbria and Wales are mainly the way they are due to the grazing of sheep preventing regeneration of woodlands. Woodlands should not be planted over other species-rich habitats, but where biodiversity is low, and avoiding species-poor but rare habitats, too. As with hedgerows, species native to the area should be used, preferably of local provenance. Biodegradable tree-guards are recommended for protection of the young trees and shrubs during their early years. Access paths and tracks should be established early on, both to facilitate management of the woodland, and to add the valuable 'woodland ride' habitat, which is excellent for insects and other animals. Obviously, non-native grazing animals should be excluded, or at least limited to selected areas when the trees and shrubs are big enough, and browsing by deer and other wildlife should be monitored. Grey squirrels can be a particular problem in some woodlands, and where deemed necessary humane control should be undertaken. Once the woodland has become established, management will depend on the primary use of the woodland, whether for amenity, conservation, or a combination of the two.

Management of existing woodlands should aim to increase the age range of the trees, maximise the species diversity (within the context of local species), and improve the overall structure of the woodland, i.e. the different layers. Removal of old and dying trees should be avoided, and ivy-covered trees retained, as these provide some of the richest habitats. Similarly, fallen trees should be left to rot naturally within the woodland, providing a home to many insects and fungi. Most importantly, a survey should be undertaken of the woodland, before management starts, to establish the species of flora and fauna present. This will dictate the most suitable management for the particular woodland.


Martin Bailey runs Wildlife & Countryside Services, which provides a wide range of services and products on a wildlife theme, including: ecological consultancy services; habitat creation & enhancement; tree planting & felling; hedge-laying; dry-stone walling; pond creation; wildlife gardening; environmental education; species & habitat monitoring & management; supply of nestboxes, badger gates & fencing, newt & reptile fencing, biodegradable tree-guards, wildflowers, shrubs & trees. Martin can be contacted on 0333 9000927 or 07974 396699 or martin.bailey@wildlifeservices.co.uk. Web site is www.wildlifeservices.co.uk. 

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