Well looked after?

Scotland's woodlands are amongst our richest habitats and greatest assets for recreation and tourism, as well as a source of timber. Not all of them are in good condition though - some of the main reasons are:

• Over- (or more rarely under-) grazing or browsing by wild deer or domestic herbivores Over-grazing can lead to a loss of species in the ground flora and to a simplified woodland structure without shrubs or climbing species (e.g. bramble and honeysuckle). Over a long period of time, the constant browsing of seedlings and saplings can lead to a lack of young trees and ultimately to a break-down in the canopy and gradual loss of woodland area. Under-grazing can result in dense growth of bramble or other shrubs, shading out ground flora, or lower plants on the ground or on tree trunks. If chronic over-grazing is followed by complete exclusion of grazing animals, competitive ground flora species (e.g. the grass Molinia caerulea or bracken) can respond rapidly, becoming rank and preventing germination of tree seeds.
  
• Scotland's wild Deer: a National Approach   sets out the key principles for sustainable deer management in Scotland.

• Invasive species: plants, animals and pathogens Rhododendron ponticum and its invasive hybrids can form dense thickets, shading out ground flora, lower plants and preventing tree regeneration. Rhododendron is recognised as a major problem and included on the Species Action Framework. Other non-native invasive species include Japanese knotweed and non-native conifer species. These have a similar impact to rhododendron but - although they can be serious problems in some areas, they are much more localised. Native species sometimes cause problems too. Bracken can shelter woodland species like bugle and violets, and can be a valuable habitat for butterflies like the pearl-bordered fritillary. If it becomes too dense though, it casts a deep shade and a litter layer can build up, which prevents anything growing underneath it. Grey squirrels carry squirrel-pox, which kills red squirrels. They can also be very destructive of woodlands, as they eat the bark from tree trunks and branches. Phytophthora ramorum/ kernoviae spread via Rhododendron ponticum; these pathogens have been found in several nurseries and gardens on the west coast of Scotland. The most common hosts so far have been ornamental species of rhododendron and other trees, although they can also infect native trees and have been found on the native blaeberry.
  
• Fragmentation/ isolation Some of our woods are very small and - especially in the lowlands - may be isolated from other semi-natural habitats. Smaller woods are more likely to lose populations of species, and isolated woods are less likely to acquire new populations from nearby habitats.

• Climate change is likely to affect woodlands as well as other habitats. The predictions for likely changes in future climate suggest that Scotland will become warmer but, although rainfall may decrease in summer, winters are likely to become wetter. The impact this will have on Scottish woodlands is uncertain - a warmer climate may encourage the spread of pests and pathogens currently more associated with the south of England, or cause existing problems to become more common. Drier summers may increase stress in species susceptible to drought (e.g. Sitka spruce) and lead to declines in some rare western lower plants - although wetter winters might restrict the impact. What we can be sure of is that things will change - it is likely that new pests will arrive and different species of tree will be more or less affected. Without a precise understanding of what will happen, we can best protect our woodlands by managing them to be as healthy and well connected as possible, so that they have the best chance of adapting to changing conditions. Follow this link to more on climate change.

• Lack of management/neglect Most of Scotland's woods have been managed in some way throughout their history - for timber, charcoal, grazing and many other products and services. Their structure and composition today is the result of all these centuries of interaction with people and their livestock. The cost of management, and the low value of many woodland products, means that it is often not economically viable to continue to manage them. Whilst this does not always lead to a decline in their value for wildlife, in some cases it may do. If woodlands are not managed because they are not valued, they may become more vulnerable to over-grazing or invasive species. Alternatively, uncontrolled growth of young trees may prevent light reaching the ground, leading to a loss of ground flora species or to the decline of large old trees which cannot compete with the vigorous young growth. This may be a particular problem in former wood-pastures where pollarding has previously been carried out and the older trees are shorter than the new trees growing up around them. Such old trees can be very valuable for the lower plants and fungi that they support.

There are several sources of information that tell us how are woodlands are doing:

• Site Condition Monitoring Scottish Natural Heritage monitors the condition of designated sites on a six-year cycle. Most sites are either in favourable condition or recovering, but some aren't. The two main reasons for sites failing to reach favourable condition are over-grazing by deer or livestock and invasion by non-native species, especially rhododendron.
• The Native Woodland Survey for Scotland   FCS are carrying out a survey of all of Scotland's native woodlands    The results will start to become available from December 2009 and when this is complete it will give us a better understanding of the condition of our woods than we've ever had before.
• Forest Condition Survey Forestry Commission monitors annual changes in the condition of Britain's forest trees   by assessing the status of five forest species via a network of monitoring plots distributed throughout the country. The results of this monitoring is analysed at a GB level.