Peat is made of incompletely decomposed plant remains, mainly sedges, grasses, reeds and mosses. It forms when the natural processes of decay are arrested by waterlogging and the exclusion of oxygen, with the remains of succeeding wetland plants becoming compacted to form peat. It is a slow process with the layer of peat increasing by an average rate calculated to be no more than 1mm depth per year. It is used in horticulture for its unique characteristics that make it an ideal growing medium.
Where does it come from?
Existing peatlands cover about 4 million km2 of the land and freshwater surface of the planet and are found throughout the world. Currently though, peat formation is occurring mainly in the northern temperate zone.
In the United Kingdom peatlands cover 1.6 million hectares, 95% of which is upland blanket bog and the remainder is lowland raised bog. Not all peat types are suitable for commercial extraction and it is the lowland raised bog, composed of deep sphagnum moss peat, that gives rise to most of the product destined for horticulture. According to Naasz et al. (2009) “growing media manufacturers prefer slightly decomposed peat, which constitutes only 20% of the peat volumes available in peatlands”. Of the 70,000 hectares of lowland raised bog in the UK, estimates suggest that only 3,800 – 8,000 hectares remain in pristine or near-natural condition.
Suitability for commercial extraction is determined by many factors, such as its proximity to market, ease of access to the peat itself and peat quality. It is these factors which make lowland raised bogs attractive to commercial extraction operations. It is also for these reasons that the global volume of peat suitable for commercial extraction is much lower than the figures presented as the remaining peat reserves; replenishment figures have to be looked at closely. Global replenishment rates are based upon the global peat reserves and not the reserves that are commercially extractable. Peat that is growing beyond commercial reach cannot be said to replenish a renewable resource (Schilstra,2001). According to the Environment Agency, “over human timescales, the loss of peat is irreversible due to the slow rate of natural regeneration”.
Peat extraction and use
The effects of extraction are irreparable as peatlands take thousands of years to form. Reclamation schemes at previously worked sites have succeeded in creating attractive wetland areas, but they have not recreated peatlands. Peat forms at a rate of only 1mm per year, whilst peat extractors remove up to 22cm a year. A 10m deep peat reserve, which took around 10,000 years to form, will be cleared in less than 50 years. Bearing these timescales in mind, it is impossible to illustrate rehabilitated and restored peatlands. Even if peatlands could be restored, it is important to remember that preservation is cheaper than restoration.
Defra (Department for Environment, Food and Rural Affairs) estimate that 2.96 million m3 of peat is used in the UK annually, of which 99% is used as growing media and 69% of which is used by gardeners. Sixty-eight percent of all peat used in the United Kingdom is imported from other countries, incl. the Republic of Ireland and the Baltic states (Defra, 2010).
Legislation
Until recently, horticulture was focussed on achieving UK Government targets for reducing peat use by 2010. Major retailers (e.g. B&Q, Homebase, Focus and Marks & Spencer) sought to match or better these targets. It was hoped that such leadership would encourage commercial nurseries away from using peat.
The Growing Media Initiative (GMI), a scheme involving the Horticultural Trades Association, the Growing Media Association, retailers, Defra, the RSPB and the RHS, aims to encourage the horticultural industry in the UK to reduce peat use in line with government targets.
The European Union shares concern about peatland preservation. Most peatlands are now so rare that they are being designated as Special Areas of Conservation and member states are required to protect them. The EU also advocates the view that preservation is cheaper than restoration. Outside the EU, the special conservation status of peatlands is increasingly recognised, though with variable legislative effectiveness.
Defra consultation
Previous Defra targets for peat use in 2010 were not achieved so, on 17 December 2010, Defra announced the launch of its revised consultation on horticultural use of peat.
The salient points of the consultation are that Defra recognises the different challenges facing the amateur and professional markets and has therefore proposed that peat is phased out by 2020 for the amateur gardening market for bagged growing media and by 2030 for professional growers.
The salient points of the consultation are that Defra recognises the different challenges facing the amateur and professional markets and has therefore proposed that peat is phased out by 2020 for the amateur gardening market for bagged growing media and by 2030 for professional growers.
A shared interest in protecting peatlands
The following organizations are among those with a shared interest in the protection of peatlands as a wildlife habitat:
The Royal Society for the Protection of Birds, The Lodge, Sandy, Beds, SG19 2DL, tel 01767 680551
The National Trust, Conservation Department, Heelis, Kemble Drive, Swindon SN2 2NA tel 01793 817400
Plantlife, 14 Rollestone Street, Salisbury, Wiltshire, SP1 1DX, tel 01722 342730
The Wildlife Trusts, The Kiln, Waterside, Mather Road, Newark, Notts, NG24 1WT, tel 01636 677711
Friends of the Earth, 26-28 Underwood Street, London, N1 7JQ, tel 0207 490 1555
Natural England, Northminster House, Peterborough, PE1 1UA, tel 0845 600 3078
Countryside Council for Wales, Maes-y-Ffynnon, Penrhosgarnedd, Bangor, LL57 2DW, tel 0845 1306229
Scottish Natural Heritage, Silvan Hs, 3rd Floor East, 231 Corstorphine Rd, Edinburgh EH12 7AT tel 0131 3162300
Joint Nature Conservation Committee, Monkstone House, City Road, Peterborough, PE1 1JY, tel 01733 562626
Growing Media Initiative The HTA, 19 High Street, Theale, Reading RG7 5AH tel 0118 930 3132
References
Naasz, Caron, Legault and Pichette (2009)
Efficiency factors for bark substrates: biostability, aeration or phytotoxicity. Soil Science Society of America Journal, 73(3) 780-791.
Schilstra, A.J. (2001)How sustainable is the use of peat for commercial energy production? Ecological Economics, 39 285-293. also available online at www.rhs.org.uk/publications
Defra. (2010).
Monitoring of the horticultural use of peat and progress towards the UK biodiversity Action Plan target. Department for Environment, Food and Rural Affairs, London, pp. 19.