Wet woodlands bring diversity to open, upland landscapes. These small, patchy woods are often the only relief from closely grazed grasslands or moorland. Within both open landscapes and forestry, wet woods add nature conservation value out of proportion to their area, supporting wetland, fen or marsh flora.

Riparian woodlands have an important role as a link between terrestrial and freshwater ecosystems. These woodlands influence the health and productivity of rivers and burns and also provide exceptional value for nature conservation and amenity. Tree roots stabilise riverbanks, capture and recycle mineral nutrients and promote biodiversity both on the bank and in the watercourse. Riparian woodland can also buffer rivers and burns from the negative influences of adjacent conifer plantations and agriculture.

The following table (table 1) lists local priority species that are likely to occur in wet and riparian woodland in North East Scotland (P = UK Priority Species, C = Species of Conservation Concern, L = Locally Important Species). The species listed are largely restricted to riparian and wet woodland, or rely on riparian woodland for maintenance of habitat and water quality. These species are, therefore, likely to benefit from this action plan. Other local priority species may well benefit from sympathetic management of these habitats, but it is unlikely to contribute significantly to their conservation, as other habitats are of greater importance. Other associated species including: - water shrew, reed bunting, grasshopper warbler, dipper, tree pipit, water rail, palmate newt, common toad, a stilletto fly (Thereva lunulata), a cranefly (Rhabdomastix hilaris) and Northern blue damselfly, will be further considered in the Wetland HAP (North East Scotland LBAP). Interactions with red squirrel, water vole and beaver are discussed below.

There are potential conflicts between the establishment of riparian woodlands and some priority species. Water vole and red squirrel are the subject of local species action plans (NE Scotland LBAP). Opportunities to reintroduce beavers to appropriate wooded straths are being explored.

Water voles require grassy watercourse margins. A large expansion of riparian woodland at the expense of grassy water margin would reduce the availability of suitable habitat for this species. The water vole population is currently threatened by mink predation and clearance of suitable riparian grassland vegetation for agriculture. Woodland restoration is not thought to be a major factor in survival of the water vole population, however, this potential for conflict will be considered at all proposed restoration and enhancement sites.

There is concern over the spread of grey squirrels, particularly along Deeside, from Aberdeen. Establishment of large-seeded trees in networks along the riparian zone could increase problems for red squirrel conservation by encouraging the spread of the grey squirrel population into red squirrels habitat. Native riparian and wet woodland species are, however, predominantly small-seeded (alder, willow, aspen, birch, ash, rowan, wych elm) and do not encourage grey squirrels.

Beavers require a substantial area of wooded riparian habitat. It is important to establish networks of good quality riparian woodland habitat to create sites with the potential for successful re-introductions in the future. Beaver re-introductions in areas where riparian wooded habitat has been restored to a suitable level would bring major benefits to the riverine ecosystem.

Species rich grassland is a rare and declining habitat in NE Scotland. Altering grazing or mowing regimes on existing semi-natural grasslands will result in the loss or degradation of this habitat. This action plan will be balanced with the habitat action plan for species-rich grassland ensuring that woodland creation projects do not degrade existing species rich grassland sites.

Livestock access to riparian margins throughout the year can result in over grazing and poaching, causing erosion and preventing regeneration. High levels of browsing and grazing by wild deer and rabbits can add to over grazing problems.

In many areas channelisation and culverting has replaced burns and associated trees with straight channels and underground drainage pipes. Abstraction and discharge can alter flow rates and deposit pollutants. Dumping of rock and sediment and infilling can alter flow rates and cause erosion.

Drainage of wet woodland or associated land for agriculture, forestry or development has resulted in the loss of functional floodplain woodland.

Clearance of wet and riparian trees for agriculture, development, flood prevention and fisheries management has resulted in increased bank erosion, channel widening and direct loss of habitat. Continued clearance of riparian and wet woodland also increases the isolation of remaining stands and associated species. Fertile alluvial flood plains have been cleared for agriculture, making alluvial forest a threatened habitat at a European scale. The value of this alluvial land for agriculture is an obstacle to the development of new riparian and floodplain woodland. Sufficient funding is, therefore, essential to support riparian and floodplain woodland creation schemes.

3.4 Introduction of invasive and non- native species

Invasive species such as giant hogweed and Japanese knotweed shade out the woodland ground flora and prevent regeneration. Non-native tree species, such as a sycamore, cast deeper shade than natives and do not support the same diversity of species as native trees.

Succession of wet to dry wood is a natural process that maintains a diversity of woodland types. This relies on sufficient habitat being available for these dynamic processes to operate.

From time to time our native trees suffer foliage loss due to a variety of causes. However, there are two conditions, Phytophthora disease and Crown Dieback, which pose a threat to the health of the alder population. Phytophthora disease is caused by a fungus, which typically infects and spreads through riverside alders via free-swimming spores. It has now become a serious problem in England and Wales with restrictions on the movement of alder planting stock north of this area. A handful of confirmed cases have been reported in Scotland. In contrast, the cause of Crown Dieback in alders is unknown. Within the last decade it appears to have become widespread through out the Highlands. The Forestry Commission is currently conducting research into these diseases.

Although planting of conifers in the riparian zone is no longer common practise there are many existing sites where conifers are planted adjacent to water courses. The FC Forest and Water Guidelines suggest a buffer of 5-20 m depending on width of watercourse. Conifers cast heavy shade throughout the year. As they are shallow rooting, planting adjacent to watercourses can destabilise banks. The spawning and nursery potential of many tributaries remains degraded because of methods of afforestation undertaken before the Guidelines were in place.

Surveys of several NE rivers have been carried out by SEPA and other organisations using the standardised River Habitat Survey (RHS) technique. RHS provides a valuable initial audit of river structure and vegetation including information on woodland cover and individual trees. Many DSFBs now have a biologist on their staff actively involved in river surveys, including habitat.

Scottish Native Woods have produced and distributed a very practical guide to inform landowners and managers of the ecological and commercial value of riparian woodlands and the financial incentives available to conserve and manage them.

The Cairngorm Straths Environmentally Sensitive Area (ESA) Scheme has provided grants for fencing off riparian trees/ woods and planting small numbers of trees in buffer strips. The Countryside Premium Scheme (CPS) included the option to fence off buffer strips along watercourses.

The Rural Stewardship Scheme (2001 onwards) will combine CPS and ESA and is expected to make provision for protection and enhancement of riparian woodland.

Larger-scale planting or management of riparian and wet woods is supported by the Farm Woodland Premium Scheme and the Woodland Grant Scheme. Establishment of new woodland cover on arable or improved grassland that may have been converted from wet or riparian woods in the past is encouraged. Woodland Improvement Grants (WIGs) are available from FC to support one-off woodland biodiversity enhancement projects including schemes to enhance riparian and wet woodland.

4.5 Forest and Water Guidelines

The FC Forest and Water Guidelines outline best practice for the management of forestry adjacent to watercourses. To comply with this guidance FE are improving the management of all riparian forest during felling and re-planting, this involves converting or rehabilitating areas of riparian woodland from stands of exotic conifers.

The following initiatives concerned with riparian forestry, environmental protection and habitat restoration are proposed or in progress:

• The Dee River Catchment Management Plan is under development (SEPA).

• The North East Rivers Project promotes the sustainable environmental management of Aberdeenshire’s river catchments, through promotion of best practice, awareness raising and demonstrations projects.

• Phase 1 of the Ugie Project created buffer strips on agricultural land. Options for continuation of the project are being explored.
• The Ythan Project Plan incorporates a wide range of improvements for the catchment including the use of habitat surveys and the creation and enhancement of buffer strips on agricultural land.
• Birse Community Trust are developing a community action plan, which will have rivers and riparian woodland as one focus.
• The Tarland Catchment Initiative is promoting buffer strips and riparian tree planting, predominantly in agricultural areas.
• Dee District Salmon Fisheries Board are developing a funding package for creation of buffer strips and associated enhancement/planting of riparian woodland.
• A catchment management plan has been developed for the River Deveron and a River Habitat Survey has been completed.

• Moray Forest Enterprise are hoping to make a strategic contribution to expansion in floodplain woodland.
• North East Native Woodlands is an EU funded Initiative providing free advice on the management of riparian and wet woodlands.

Enhancing and restoring wet and riparian woodland will bring significant benefits:

Wet and riparian woodland habitats support a varied fauna and flora. Riparian habitats are valuable as wildlife corridors, especially in intensively managed farmland or forest where they also act as buffer strips. Riparian buffer zones benefit fisheries, preventing siltation of spawning areas, providing shade and shelter and feeding for fish. Riparian woodland is often the only habitat for woodland birds in open, upland landscapes.

Wet and riparian woodland is important for the aquatic habitat. Woody debris fallen from riparian trees provides a substrate and food sources for many plant and animal species. Leaf litter and terrestrial invertebrates fall into watercourses providing a resources for fish and invertebrates. Shade from appropriate native trees buffers water temperatures, preventing lethal temperatures for invertebrates and fish and preventing excessive growth of water weed. Permanent tree cover can improve water quality by trapping sediment and filtering associated nutrients in leachate or run-off from adjacent agricultural land and plantation forestry. Fallen branches and tree roots trap sediment, provide shelter and create pools suitable for salmonid feeding.

Burn and river banks are stabilised by the presence of riparian trees reducing the risk of erosion, stream widening and excessive siltation of streambeds and allowing vegetation to establish. Stable banks encourage deep water in burns and rivers and root systems provide suitable areas for otter holts.

Wet and riparian woodland enhances the landscape, providing natural features which can be well-suited to the provision of public access.

Some of the ancient wet woods of Scotland have a recent history of coppice management. Restoring traditional coppicing techniques would maintain appropriate woodland cover for river health and potentially provide a source of income from the woodland.

The UK Biodiversity Action Plan for wet woodland aims to maintain the current extent of semi-natural wet woodlands and encourage a balance of appropriate management regimes. Restoration targets have been set for former areas of ancient semi-natural wet woodland and creation targets for expansion by natural colonisation and planting. (UK Biodiversity Group Tranche 2 Action Plans, Vol II, 1998).

Maintain current area of ancient semi-natural wet woodlands.

Initiate restoration of 3,200 ha to native wet woodland.

Create, by colonisation or planting 6,750 ha on unwooded or ex-plantation sites.

Maintain and enhance the extent and status of the current resource through appropriate habitat management, habitat creation, data collection, promotion, education, liaison and legislation.

Targets – No loss of existing riparian and wet woodland habitat. Restoration of all degraded sites which retain native species by 2010. Establishment of 20 habitat creation projects by 2010.

Objective 1: Establish/maintain effective conservation management at existing sites.

Target: Prevent and/or reduce threats to the resource through continuation/ introduction of established management techniques at all identified sites (see objective 5).

Time: By 2005

Objective 2: Enhance and restore degraded and fragmented wet and riparian woodland sites.

Target: Survey and assess all degraded sites, identify restoration priorities, progress phased restoration.

Time: by 2010.

Objective 3: Expand the area of wet/riparian woodland through habitat creation and management.

Target: Expand the resource by planting and regeneration to achieve a total of 20 projects, of a range of sizes, at appropriate sites.

Time: by 2010.

Objective 4 : Ensure no loss in the key biodiversity associated with riparian and wet woodland.

Target: No net loss in the number and/or range of key species associated with riparian woodland.

Time: By 2010.

Objective 5:Set up a mechanism to protect the genetic integrity of populations of wet woodland during management and restoration work.

Target: Set up a protocol and supply stock for planting work on a catchment by catchment basis.

Time: By 2005