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Industrially Harvested Peatlands - Options for the Future

Reclamation of peatlands has been carried out since the 1700's, when the first incentive payments for the drainage of bogs for pasture or tillage were made. The reclamation of fens by drainage and fertilisation was most successful, as this peat type was generally relatively shallow, and the peat was mineral rich. Reclamation of cutover bogs involved intensive drainage and mixing of the surface peat with lime, domestic fuel ash, sea sand, kelp and/or manure. Reclaimed cutover bog was generally used for grass production.

One of the largest obstacles to large scale peatland reclamation arises from ownership difficulties, stemming from indeterminate boundaries with adjoining properties and turbary and grazing rights on the land. To highlight the extent of the fragmentation, in 1977, when Bord na Móna was purchasing peatlands for large scale industrial harvesting, the average area of bog purchased in each transaction was 1.6 hectares ! (Conry 1978).

The future utilisation of industrially harvested peatlands, which may amount to 88,000 hectares, has been the subject of much research and investigation since the 1950's. Various enterprises have been studied, and a brief description of their outcome is presented below.

Grassland
Experimentation into grassland production on industrial cutaway bogs started in the 1950's. Initially, grass was sown directly into the peat surface, but major problems were soon encountered, particularly the emergence of fossil timber, uneven subsidence of the peat and cracking of the peat surface. Other problems also arose from the lack of soil disruption, including poor grass growth due to inadequate mixing of the peat and lime, and trafficability problems due to wet hollows.

To remedy these problems, a three year reclamation programme was undertaken, in preparation for grassland production. This consisted of deep ploughing the peat and sub-peat mineral soil to a depth of 75 cm and leaving it to weather for 12 months. All fossil timber was exposed and removed. In the second year, the peat and subsoil were thoroughly mixed with a cultivation disc and the area was levelled. In the third year the area was finally levelled, cultivated and sown with grass seed. This intensive cultivation treatment produced very high quality grassland and indeed preliminary research concluded that grass was the most suitable crop for milled peat cutaway bog. Grassland production is ongoing in areas that are high above the water table (free draining) on suitable peat and sub-peat mineral soil substrates.

Arable Crops
Vegetable crop production was investigated by An Foras Talúntais on deep (200 cm), cutaway fen peat in the 1960's and 1970's. Many vegetables were grown, including onion, carrot, celery, cabbage, beet, cauliflower, potatoes, broccoli, cereals, french beans, peas and lettuce. Cereal trials were also carried out on shallower peat residues. Overall, the performance was very disappointing, as yields were generally low. The main causes were nutritional problems, soil moisture deficits and disease. The provision of shelter and adequate additions of major and minor nutrients were the most important husbandry aspects. Arable crop production is no longer seen as a viable option on the cutaways.

Research has also been carried out to investigate the success of horticultural crops, such as Blueberries, Cranberries, soft fruits (Strawberries, Black currants, Gooseberries and Raspberries). Cranberry production was undertaken as a commercial enterprise for a number of years, but has now ceased. Frost is the main limiting factor for soft fruit production.

The production of turf grass sod has been very successful on organic soils in Michigan in the United States of America. The resulting sod is lighter and easier to handle when grown on organic soils, although it requires specialist equipment and a suitably deep peat residue. Grass sod was commercially produced at Lullymore Teagasc station under the direction of Williams-Waller Ltd.

Energy Production
It was suggested that growing trees for biomass (energy) production on the cutaway bogs would produce a renewable energy source that could be used to fuel the existing power stations in the midlands when the peat resource was exhausted. Research into the growing of short rotation forestry for biomass commenced in 1976 on cutaway peatlands. The trials investigated species selection, spacing, fertiliser, yield, harvesting methods and combustion. Some physical problems encountered were due to temperature and drainage. The most successful tree species were Sitka spruce and lodgepole pine. More extensive trials with rooted Willow species were also carried out. The project failed for both technical and financial reasons.

Sine 1992, Irelands first commercial windfarm has been operating at Bellacorick in County Mayo. It is located on an area where milled peat production has ceased. The wind farm comprises 21 wind turbines and produces enough electricity to supply 4,500 households. The nearby location of the peat-burning power station, which is linked to the National Grid, has facilitated the delivery of the generated electricity to consumers (Irish Energy Centre).

Forestry
Coniferous plantations have been established on sizeable areas of hand cutaway raised bogs and modified fen peat in Ireland since 1950. Norway spruce and Scots pine were the most commonly planted species on these site types. Forest productivity varies considerably, due to tree species, previous cultivation and depth of peat. In addition, nutritional problems have occurred along with unexplained falls off in growth and the occurrence of shoot dieback.

In 1955, 13 hectares of forest trials were established on sod cutaway bog at Trench 14 in Clonsast, Co. Offaly. A wide range of coniferous and broadleaved tree species were planted. The results were encouraging and many species grew satisfactorily with a minimum of inputs. The most promising trees included grand fir (Abies grandis), coastal lodgepole pine (Pinus contorta) and monterey pine (Pinus radiata). Sitka spruce (Picea sitchensis) failed on some plots due to inadequate peat depth, while it was quite successful on other plots.

Because of the success at Trench 14, afforestation was seen as an attractive option for milled peat cutaway bogs. Large-scale afforestation of milled cutaway bogs began in 1988, with 3000 hectares of cutaway bog being planted with trees, mainly sitka spruce (76%). Despite the obvious potential of the cutaway peatlands for forestry, to date, their afforestation has been a failure. An intensive survey of these plantations carried out in 1994, indicated that as much as 58% of the trees established on the midland cutaway bogs may have failed (Jones and Farrell, 1997). The main causes of failure were frost, vegetation competition, nutritional problems and pest damage.

The optimistic yield class predictions of the late eighties for plantations established on cutaway bog, were based on research carried out on sod cutaway bog. Large-scale afforestation of milled cutaway bog was initiated without adequate research into establishment and management techniques being carried out for this particular site type. Research into the afforestation of milled cutaway bogs is on-going.

One of the more interesting and unexpected developments on the cutaway bogs, is the extent to which birch (Betula species) have grown naturally on the milled cutaways. Some areas, which were initially planted with conifers, have now developed largely into a birch woodland. In the present climate of increased environmental awareness and the need to protect and indeed promote biological diversity, this new development has led to change in perception of what is "successful" afforestation. The sustainable forest management strategies that are being implemented specifically require the maintenance and enhancement of biological diversity and nature conservation (Coillte, 1999).

Amenity
At present, there are large areas of Bord na Móna bogs that need to be pumped, to keep the water table level down to facilitate mechanical peat extraction. The costs of maintaining the pumping facilities will make many future land use options unviable. Such areas will probably be allowed to reflood, once peat extraction has ceased.

A comprehensive amenity resource has been created at the Lough Boora Parklands in County Offaly. Here, there has been the creation of artificial lakes, some of which have been stocked with fish, the development of walkways with information and interpretive points, bird hides, car parks and picnic areas. Close by, there is a 60 hectare area of naturally revegetated wetlands (Turraun), which is both a great amenity resource, and also an area where scientific studies can be carried out (Anon, 1999).

Such areas, estimated to be up to 30 to 40% of the cutaway bogs, can provide extensive areas of amenity wetland, which may have a tourist potential for coarse fishing or boating. These flooded areas could be a valuable wildlife resort as many winter migrants may utilise these wetland habitats. Those areas that are located close to the Shannon river and near to the large population centres, especially Dublin, would have the greatest potential for generating tourism revenue.

While many investigations into the future utilisation of cutaway bogs have been unsuccessful, there are three main enterprises which will most likely constitute the bulk of the uses for this new land resource. It has been estimated that approximately 40 to 60 % of the land will be afforested, 15 to 25% will be converted to grassland, and 30 to 40 % will be utilised for amenity purposes. However, it is most important that the future utilisation of this land area will be carried out on the basis of a land-use plan, which will not mean that there will be one large block of any single enterprise, rather a mosaic of land uses all interspersed in the landscape. This is due to the fact that the cutaway bogs are a complex environment, which a range of different peat types and peat depths, with a range of different sub-peat mineral soils lying beneath them. There is no simple mathematical formula that will allow us to allocate large blocks of industrial cutaway bog to any single enterprise, guaranteeing its success, rather a detailed scientific investigation, drawing on the successes and failures of over forty years of research. One of the most significant findings of these studies is the complexity of the resource and the need for imaginative and innovative solutions to the wide and varied problems of the industrial cutaways.

References and further reading
Anon., 1979. Interim report of the inter-departmental committee to consider possible uses of Bord na Móna cutaway bogs. The Stationery Office, Dublin. 15 pp.
Anon, 1999. The future use of cutaway bogs. Lough Boora Parklands. Proceedings from the first comprehensive conference on cutaway bogland rehabilitation. 80 pp.
Coillte, 1999. Coillte's Forests. A Vital Resource. Coillte Teoranta, the Irish Forestry Board, Leeson Lane, Dublin. 56.pp.
Conry, M., 1978. Future Use of Midland Bogs. Irish Society of Agronomy and Land Use Symposium, Tullamore, February 1978. 56 pp.
Irish Energy Centre. Bellacorick Wind Farm. OPET case study 1. Glasnevin, Dublin 9. 2 pp.
Jones, S. and Farrell, E.P., 1997. Re-survey of Plantation Forests on Bord na Móna Cutaway Bog. BOGFOR2 project, Final Report. Forest Ecosystem Research Group Report number 23. Department of Environmental Resource Management, University College Dublin. 55 pp.
Mollan. C. (Editor) 1989. The Utilisation of Irish Midland Peatlands. RDS, Dublin 78 pp.

Copyright Gillian Boyle
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University College Dublin

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