1.2 Most plantations are stands of exotic species, planted during the 20th century. They are often dense, even-aged monocultures, but suitable opportunities are being taken to restructure and diversify them, e.g. as they reach harvesting age. A high proportion of recent plantations of native species are classed as 'new native woodlands' and will be managed according to the guidelines for semi-natural woodlands.
1.3 Semi-naturai woods have originated mainly through natural regeneration. They may be coniferous, broadleaved, or mixed in composition, and are composed predominantly of native species. They tend to have a more 'natural' appearance than plantations, with greater variation in tree age and greater structural diversity.
1.4 The character and ecology of rural and urban landscapes, and opportunities for recreation, are greatly influenced by woodland. Semi-natural woodland is an especially important habitat for native plants and animals. It provides game habitat on sporting estates, enhances the biodiversity of farmland, and creates an attractive image for tourism. Good plantation design is vital to watercourse management; to protect against heavy run-off, acidification and erosion, and to maintain the quality of the habitat for fish and other freshwater life.
1.5 Plantation forestry is important, both socially and economically, in many areas of rural Scotland. In 1993-94, commercial forestry and primary wood processing accounted for over 10,000 jobs in Scotland (SNH, 1998). By 2000, about 90 km2 (0.8% of the total area of plantation) was felled annually and the value of Scottish timber production (at the forest gate) was around £100 million per year. As nearly half of Scotland's plantations are less than 30 years old, production is expected to double by 2015 (Figure 1) (Forestry Commission, 1999). Ease of extraction and transport, timber quality and the buoyancy of world prices will, however, influence harvesting patterns.
Figure 1. Volume of softwood timber, felled and forecast
1.6 The ecological value of semi-natural woodland, in terms of the diversity of plant communities and species present, is often closely related to woodland age and origin. There are three categories of historic woods:
■ Ancient woods of semi-natural origin (ASNO) appear as semi-natural woods on maps from 1750 or the mid-1800s, and have been continuously wooded to the present day. Where such woods have subsequently been planted up they are known as Plantations on Ancient Woodland Sites (PAWS), in such cases, surviving ground flora and native trees can provide a basis for restructuring and restoration.
-Long-established woods of plantation origin (LEPO) appear as plantations on maps from 1750 or the mid-1800s. Native species of local provenance were generally used. These sites have been continuously wooded to the present day, and many have developed semi-natural characteristics.
■ Other woods appeared on the 1750 maps, were absent from those of the mid-1800s, but are present today. These sites may not have been continuously wooded but are, nonetheless, of historic interest.
1.7 Ancient woodland is a highly fragmented (most of the 14,500 ASNO sites are smaller than 10 ha), but vital part of Scotland's natural and cultural heritage (Table 1).
Table 1 Origin and composition of historic woodland (1999)
1.8 Neglect, overgrazing and replacement planting with exotic conifers have contributed to a decline in the area and quality of Scotland's semi-natural woodland. An appreciation of their broader environmental, economic and social benefits is now contributing to their revival.
