Management of heathland
At the core of the Hampshire Heathland Project are efforts to restore areas of heathland that have been lost to scrub or conifer plantations.
The main management techniques are:Tree felling and removal Bracken management Mowing Heather
Coppicing shrubs Tackling invasive species Grazing
Tree felling and removal
Birch and pine grow particularly well in acidic soils and, when left unchecked, can soon encroach on open heathland, eventually shading out heather and other plants. Heather can survive in areas where the sunlight can get to it but the patchiness of these areas makes them unsuitable for many of the animals and other plants that would otherwise grow and thrive. Trees stop sunlight reaching the ground to give the vital warmth that many heathland plants and animals require. Conifer plantations and woods that have grown on former heaths are often dominated by a few species of trees and are therefore not as valuable to wildlife as older, more varied, woods.
Heathland plants are quick to recover once trees are removed; many pine plantations retain a straggling heather understorey where light permits. Heather seeds have been known to survive for over 75 years, buried in the soil and waiting for a chance to germinate given the opportunity.
Limited numbers of trees are a vital component of the heathland habitat and so many are left. A scattering of trees of various ages is beneficial to all sorts of species, particularly insects and birds.
Trees are usually felled by hand (with a chainsaw) and will be burnt on site or taken away and used for log fires. In some cases (usually when larger areas are being cleared and the timber is of the correct quality) the material can be chipped and taken away to a biofuel energy plant for the production of electricity. It is important to remove as much of the wood from these operations as possible to maintain the low nutrient status of the soil. 'Brash' such as branches and trunks left to rot down would have the same effect as compost, enriching the soil and creating an advantage for non-heathland species.
In some areas birch may be cut and used for making coppice products such as besom brooms or for horse jumps. The Hampshire Heathland Project researches potential uses for the timber produced and works closely with contractors, heathland managers, and statutory organisations to identify the best use of these products. Unfortunately, due to the cheapness of foreign imports into the UK, there is a very poor market for local timber products (however see the Woodland Project).
Bracken (Pteridium aquilinum) is a native plant which forms dense stands on many heathland sites and shades out less vigorous plants. The litter created by dead bracken forms a dense carpet, also inhibiting other plant growth. Whilst being an important part of a heathland flora in small quantities, large stands of dense bracken are undesirable.
Spraying aims to restrict this plant to areas where it has less impact on the heathland flora. Treatment takes place in the summer when the plant is at it’s stage of maximum growth and before it begins to die. The herbicide used is fern specific and does not affect the surrounding heathland vegetation.
Only qualified operators and experienced contractors or site staff undertake these operations. Other methods exist but annual herbicide treatment for up to 4 years is the most effective means of complete eradication. On organic sites, where chemical treatment is not allowed, cutting, rolling or ‘bruising’ methods are employed. In some areas the plant is harvested for making compost. (see Mendip Hills AONB).
Where bracken litter has accumulated over a long period of time it may be necessary to scrape away the resulting ‘mulch’ in order to allow the heather to re-generate. All bracken litter is removed mechanically while retaining the top layer of mineral soil. The litter is disposed of without damaging existing habitats.
Traditional land management and use of heathland products would result in heather of uneven age. This mosaic of different ages is optimum for biodiversity – i.e. maximum number of species are able to use the area. Traditionally the cutting of turves for fuel, and the cutting of heather for broom making and thatch would have been carried out on a rotational basis. Today where there are large areas of even aged heather, mowing will break up the age structure and create a diversity of habitats. Regrowth of young shoots benefits species like silver studded blue butterflies, and the creation of bare ground and short turf benefit species such as woodlark, tiger beetles, sand wasps, marsh club moss and sundews.
Mowing reduces the ‘biomass’, contributing to the low nutrient status of heathlands. Mowing also has the added benefit of creating fire breaks which can reduce the impact of accidental burns.
Heather mowing has been successfully carried out at Woolmer Forest and some of the harvested heather seed has been used in heathland restoration on a neighbouring site.
Gorse is a useful heathland plant providing shelter and food for many insects and birds that eat them, such as the Dartford Warbler. Traditionally gorse was cut and used for animal fodder and for firing bread and clay ovens (it has a high oil content helping it burn very easily). As with other heathland plants, it would have been coppiced in rotation and would rarely have grown into the impenetrable stands found on some heathlands today.
Gorse loses its value to wildlife with age as most species prefer it compact and bushy. In modern management gorse is coppiced when it gets old so that new growth can begin. In areas where there are large dense stands that impinge on heather, the gorse can be cut and the stumps treated with herbicide to ensure minimal grow back. As with management of heather, the control of gorse can be very important to minimise the severity of accidental burns.
Tackling invasive species
The most prevalent ‘invasive’ species on heathland is rhododendron. The Himalayan native Rhododendron ponticum has done very serious damage to heathlands and woodlands of the British Isles. Rhododendron is suited to the nutrient poor acidic conditions of heathlands and grows vigorously to the detriment of other plants. It not only shades out beneficial heathland species but is poisonous and therefore eaten by very few grazing animals or insects. No plants grow beneath it. Pulling the whole plant out by its roots and burning is the best form of control. Where this is not possible it can be cut and treated with a herbicide.
Gaultheria shallon is another non-native plant that is damaging natural habitats in the UK. It was introduced from North America as cover for game. Unlike rhododendron it is grazed by cattle and deer and birds eat its berries. However, this means that the plant has a very effective means of seed dispersal and is far more difficult to control. The Hampshire Heathland Project is undertaking cutting and treatment of gaultheria at Newtown Common. Gaultheria shallon at Somerley Closed Landfill is kept under control by grazing cattle.
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