Lying on gently undulating glacial deposits between 200m and 500m above sea level, Abernethy Forest represents a continuation of the range of montane and sub-montane habitats in the Cairngorms complex. The irregular glacial topography allows marked variations in drainage and a consequent variety of different plant communities ranging from valley and basin mires to dry heaths. Much of the native pinewood of Abernethy Forest retains a high degree of naturalness and a good structural diversity in terms of varying age, height and form of trees, and the presence of a juniper shrub layer.

Abernethy Forest is famous for its northern bird species with up to 4% of the British population of crested tit Parus cristatus occurring here. It is also an important site for the Scottish crossbill Loxia scotica, capercaillie Tetrao urogallus and greenshank Tringa nebularia, as well as a number of raptors, most notably osprey Pandion haliaetus.

Many higher plant species of national and regional importance occur, including intermediate wintergreen Pyrola media, serrated wintergreen Orthilia secunda and twinflower Linnea borealis. In addition, Abernethy is the only known British locality for nine species of microfungi. The invertebrate fauna is rich in scarce or rare insects characteristic of native pinewood.

Abernethy is the most complex of the Wet Woods Restoration Project sites and thus for ease of management has been divided into four areas.

DELL WOOD

Dell Wood is a National Nature Reserve situated in the north east of Abernethy Forest, just south of the village of Nethy Bridge. It contains extensive areas of bog woodland with marked variations in the water table due to the irregular topography. Many of these bogs have been subjected to drainage and/or afforestation, particularly during the last 30 years.

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GARTEN WOOD

Garten Wood is found in the western part of Abernethy Forest, between Loch Garten and the village of Boat of Garten. It contains areas of superb pinewood and bog woodland habitat. However, the hydrology of the area has been severely altered over the years through an extensive programme of deepening, widening and/or straightening existing watercourses, plus the digging of new drains.

MONDHUIE

Mondhuie lies on the extreme northern edge of Abernethy Forest, just to the south west of Nethy Bridge village. Much of Mondhuie has been drained in the past and some of it was also planted with trees, mainly lodgepole pine Pinus contorta. The 'drained only' area extends to the south and east of the plantation area and really exists as two separate drainage systems. The main system extends over a mile south of the plantation through less damaged bog woodland. The smaller system to the east is also situated in relatively intact habitat. However, sections of the drainage channels in both systems show evidence of alteration.

NORTH ABERNETHY

North Abernethy refers to an area just south of Dell Wood where restoration efforts have been concentrated on 'drained only' bog woodland in six blocks. Overlapping one of these areas, a plantation of Scots pine is further damaging the bog.

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Targets

Within the Cairngorms SAC much of the bog woodland habitat has been damaged to varying degrees by plantation forestry and its associated extensive drainage systems. In addition, further drainage outwith these plantations has had a particularly bad effect at Abernethy. Many existing natural drainage channels have also been deepened and straightened. The effect of all this is to remove significant volumes of water from the bog woodland systems, leading to a long term overall decline in the habitat. Thus, unlike the other project sites, Abernethy has two different levels of damaged bog woodland: afforested and drained, and drained only. As the most complex of the project sites, Abernethy is divided into four management units: Mondhuie, North Abernethy, Dell Wood and Garten Wood.

Original targets (amended targets in brackets) and actual achievements:

Management

Mondhuie
Tree felling started in early July 1998 on a plantation of lodgepole pine and by November 1998, 21.7 hectares had been felled. Progress was slow due to the shape and form of the trees, many of which had several main stems. Consequently, felling was done by hand with chainsaws rather than by the cheaper harvester/forwarder method. The second phase began in November 1998 with a harvester/forwarder contract to extract the more marketable timber. This was completed by February 1999 and increased the felled area by another 24 hectares. The third phase of tree felling was carried out between August 1999 and March 2000 over an additional area of 24 hectares. A fourth felling phase at Mondhuie began in February 2000 using a harvester/forwarder contract. This was a no-cost operation as the extracted timber covered the cost of the machines involved in carrying out the work. An area of 18.5 hectares was cleared by April 2000. The final stage at Mondhuie involved felling by hand over approximately 14.1 hectares and was completed by February 2001.

The large scale of felling at this site meant that a considerable area was covered by brash. Given the scale of the removal task it was decided to leave the brash on site and compare the development of the area with other areas outwith Mondhuie where brash removal (mainly by burning on site) has taken place.

Accurate mapping at the end of the Project showed that the total area of habitat restoration amounted to 102.3 hectares, considerably exceeding the target.

Drain blocking at Mondhuie commenced in March 1999 with the damming of the two main drainage systems on the south side of Mondhuie. The principal technique involved machine dug peat dams spaced approximately 10 metres apart. A 6 tonne Hymac digger was employed to dig out saturated peat from the side or the bottom of the drain for use in construction of the bulk of the dam. The vegetation scraped off the surface of the peat was then used as a top for the dam.

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The technique is featured in the RSPB-led LIFE Project: Conservation of Active Blanket Bogs in Scotland and Northern Ireland (Contract No. B4-3200/94/770). It has proved successful in the past but relies heavily on a skilled digger operator and close quality control. By April 1999, the drainage systems across an area of approximately 47 hectares had been dammed. Phase 2 of the drain blocking took place in February and March 2000 to a high standard and in harsh weather conditions. Drains were dammed over an area of 40 hectares.

In November 2000, 14 peat dams collapsed following several days of very heavy rain. Immediate remedial work involved the removal of peat debris in drains on the site and clearing two culverts running under the adjacent public road. It was considered that the collapse was a result of the unsuitablity of peat dams to control such large volumes of water. However, the event exacerbated the concerns of a neighbouring tenant farmer and landowner who held the restoration work responsible for increased wetting of their land. The Scottish Agricultural College were therefore contracted to review the impact of the restoration work on local hydrology. Their report showed that although, as expected, tree felling had increased the water run-off, the main problems experienced on the adjacent land were as a result of recent increased rainfall and lack of maintenance of field drains. Consequently, field drains adjacent to the site were cleared and three metal pile dams were constructed in the main drain where the collapse had occurred. An additional fourth metal pile dam was installed in March 2002 to consolidate the earlier work.

All the restoration work on Mondhuie was carried out by a local contractor who had developed a high level of expertise for this type of work in the Cairngorms. Supervision was largely by the RSPB, with regular Local Operational Project Team meetings on site to assess the work. By the end of the Project 133 hectares had been hydrologically restored.

North Abernethy
Most of the work in here involved drain blocking, focusing on areas where earlier restoration had been carried out. Initially there was not thought to be any need for habitat restoration at North Abernethy but subsequent investigation highlighted the additional need for some tree removal. Local contractors removed planted Scots pine from an areas of 1.6 hectares of ploughed and planted peatland in August 1999, along with 8.7 hectares of dense, naturally regenerated Scots pine on drained peatland. A total of 10.3 hectares were therefore restored by tree removal.

The first phase of drain blocking at North Abernethy started in March 1999 as a continuation of the work at Mondhuie. The work included two techniques - complete filling of drains in two areas and the installation of peat dams at intervals along drains at two other sites. In all 13.6 hectares of peatland was restored by the end of the contract. The second phase of restoration work revisited areas where earlier attempts at re-wetting had not achieved their objectives and was carried out in the autumn of 1999. This work involved filling in the plough lines using two 6 tonne Hymac diggers in a technique not before employed at Abernethy. Initial results in these areas has been very encourging. This phase of the work resulted in the restoration of 21.5 hectares of wetland. The complexity of this area of North Abernethy meant that targets for restoration were difficult to estimate accurately, but the total area of hydrological restoration achieved by the Project, 35.1 hectares, added to previous work undertaken by the RSPB, represents a significant piece of restoration work in a very rich and diverse landscape of bog woodland in natural Caledonian woodland.

Dell Wood
Dell Wood is part of the Abernethy Dell Wood National Nature Reserve, of which some 266 hectares is owned and managed by Scottish Natural Heritage, with another 108 hectares leased from the RSPB. It contains extensive areas of bog woodland, many of which have been subject to the effects of drainage and forestry. An area to the south of Nethy Bridge was drained and planted with lodgepole pine in the 1970s, with approximately 5 hectares planted on peatland. These 5 hectares were felled (as part of a larger felling exercise designed to benefit Caledonian pinewood) in September and October 1999, after consultation with the local community of Nethy Bridge who make use of the area for light recreation. There was no adverse reaction to the Project proposals. As a demonstration of an alternative brash disposal technique it was decided that rather than being left on the site, the brash should be gathered into large heaps and later burned. Burning began in November 2000 and continued when weather and ground conditions allowed, although these operations were later delayed as a result of foot and mouth restrictions imposed in February 2001. SNH labour was used for the brash burning, augmented by contractors. Although no dams were built the felled timber was used to infill the drains and this, in conjunction with the tree removal, has resulted in the area becoming re-wetted. The area will be monitored by SNH to see if further work is necessary.

The more intact 'drained only' part of the Dell Wood bog woodland was targeted in August - September 2001, with with a contractor employed to install 30 hand built dams. This has resulted in drains being blocked over an area of approximately 14 hectares. A further proposed phase of drain blocking work was not undertaken as the area in question was shown to be prime capercaillie habitat. The original target for hydrological restoration in North Abernethy and Dell Wood was for a total of c 40 hectares. The combined total for the two areas restored by the Project is 49.1 hectares.

Garten Wood
Garten Wood contains some superb examples of Caledonian pinewood and bog woodland habitat, but the hydrology of the area has been severely affected by an extensive programme of deepening, widening and/or straightening existing natural watercourses, as well as the digging of new drains. RSPB has been active in habitat restoration in Garten Wood over the last 15 years and dammed a number of key drains. Recent investigation has shown the need to consolidate a lot of this work and extend the drain blocking programme to a wider part of the wood. Most of the Project's work was carried out in November and December of 1999 over an area originally thought to be approximately 40 hectares. Subsequent accurate mapping has shown the area of hydrological restoration to be 25.4 hectares. Plastic piling material was used to construct dams by hand in are where drain blocking had not previously taken place. In areas of consolidation new dams were constructed next to the originals, using Scots pine logs with locally dug peat infill and vegetated tops. This work was also carried out by hand to prevent excessive damage to the bog by machinery. Again, lessons learned in the previously mentioned Scottish and Irish blanket bog LIFE projects were useful here.

The extensive programme of restoration work at Abernethy was met with a mixed response from the local community. Some commended the Project but two neighbouring farmers contended that work at Mondhuie had caused flooding problems on their land. This was addressed by the report commissioned from the Scottish Agricultural College which concluded that unusually high levels of rainfall and a lack of maintenance of field drains were the main cause (see management of Mondhuie above).

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Achievements

• Drains blocked over a total of 207.5 hectares
• Trees removed from an area of 116.9 hectares
• Two new information panels installed at Mondhuie on the Speyside Way long-distance footpath. These explained the need for tree removal and drain blocking and highlighted the benefits to wildlife
• Guided visits undertaken to various areas within Abernethy for a number of parties, including Prince Charles, the Native Woodland Habitat Action Plan group, the Border Mires LIFE team and delegates from the Final Conference