COV0002
Submission from Lawrence Alderson
Submitted to the Environment Audit Committee enquiry on Biodiversity and Ecosystems
by Lawrence Alderson Consultant on conservation of animal genetic resources, Founder of Rare Breeds International and RBST, Principal of Livestock Improvement Services, Former chairman of Countrywide Livestock Ltd, Former chairman Preservation sub-committee (Defra NSC for FAnGR), Former member of Council of the Grazing Animals Partnership
Grasslands or Forests
A recent analysis by the UK Centre of Ecology and Hydrology, published on 9 July 2020, revealed that almost 2 million acres of grassland were lost in Britain in a period of 25 years, 1990 to 2015 (54% in England, 18% in Scotland, 17% in Wales, 11% in Northern Ireland). Tree planting was responsible for the majority (58%) of that loss with urbanisation accounting for the balance. The manifesto of the Conservative Party in 2019 included a commitment to plant 30 million trees per annum. Although Defra only works directly in England, with its main office in London, it maintains close links with the devolved administrations and plays the leading UK role in international negotiations, and its policy regarding tree planting is reflected in other parts of the UK, especially in Scotland. We urge government to revisit and review its policy regarding forests and grasslands.
We are aware that advice given by a recent chief scientific adviser (until August 2019) to the UK government proposed that half the nation’s farmland, mostly uplands and pasture, should be converted to forest and natural habitat thereby reducing the number of cattle and sheep by 90%. A director of Defra also has publicly advocated extensive tree planting and rewilding. We consider such advice to be misleading and misplaced. Great Britain cannot afford to replace species-rich grasslands (including heath and moorland) with monocultural tree plantations. The resulting reduction in biodiversity and loss of food production potential is contrary not only to basic requirements for sustainability, but also to the principle of moving to “a system based on public money for public goods”. One major sponsor (Nestle) already has reversed its policy for planting on a Cumbrian dairy farm because of the negative effect on biodiversity.
An ancient habitat. Grassland has fulfilled a particularly important role throughout the history of farming in post-glacial Britain. It ranges in type from lush lowland meadows through upland pastures and heath to open moorland. Some types are special and particular to Britain. More than 75% of the world’s heather moorland is found in the UK. The mild moist climate of the temperate ecosystem at the north-western fringe of Europe provides the best conditions for grass growth and enables its ability to play a major role in ensuring the sustainability of planet Earth. It provides open spaces in our congested country with its population density of more than 700 people per square mile, and provides grazing for both domestic and wild ruminants. Yet in current muddled thinking, precipitated by global warming, its importance often is ignored. It shares the temperate latitudes with deciduous forest and some ardent arboreal environmentalists regard grass as an unnecessary ingredient. Clamour for ‘wall-to-wall’ tree planting recommended by extreme proponents would see acres of grassland and heath sacrificed in a blinkered focus on trees. Trees have a part to play in the drama of climate change, but they must be kept in a sensible perspective.
Flooding risk. Several misconceptions, possibly fostered in some cases to support an agenda of self-interest, conspire to prevent a rational interpretation of the relative value of trees and grazing land. Forests are reputed to retain water more effectively and thus reduce the risk of flooding downstream. Yet the opposite may be true. Protecting and restoring peatland (part of the wetlands ecosystem), which is a major store of carbon, is a higher priority. In the northern Pennine moorland ditches have been blocked by responsible owners attempting to refresh the peat which enables it to act as a sponge much more efficiently than forests. Their efforts to deliver ‘public goods’ in compliance with governmental policy contrasted starkly with the management of neighbouring land where the Forestry Commission (a non-ministerial government department) planted huge expanses of Sitka spruce and dug ditches deep into the peat to achieve rapid drainage and thereby caused soil loss and erosion and increased risk of flooding.
Trees in perspective. Carbon sequestration creates a more serious misconception. It almost has become accepted wisdom that tree-planting is a sine qua non in the struggle to reach the target of ‘zero carbon’ by 2050. Media pundits and advisers to government have joined extremists on the planting ‘wall to wall’ bandwagon in support of trees. A very different picture emerges when emotion and prejudiced opinion are set aside. The ability of trees to sequester carbon in all ecosystems cannot be disputed; they take carbon out of the atmosphere and store it in their biomass and leaves. In a global context temperate forests are less efficient than other forest ecosystems. Northern boreal (coniferous) forests store the greatest amount of carbon per hectare with a higher proportion held in the soil. Tropical forests sequester and store more than temperate forests with 50% in biomass. Carbon sequestration is significantly lower in cooler climates and in old forests. Placing a high priority on boreal forests and tropical rainforest is justified, but temperate forests are more difficult to justify. Although they have a role to play significant negative factors should not be ignored. When a tree is harvested or destroyed the carbon in its biomass is released directly back into the atmosphere. Forest fires account for an annual loss of an area equivalent to the size of Italy (c.300K km2). They are a regular occurrence in hot and arid areas such as Australia and California, but they also occur in temperate and northern areas and are expected to increase with global warming. In 2014 there were record-breaking wildfires in Canada’s boreal forests, and in 2017 1.2 million hectares burnt in Europe. A fire in the moist mild climate of Dorset in 2020 destroyed 220 hectares of forest, just as a previous forest fire more than forty years ago (1976) in the same area burned 50,000 trees. A further 180K km2 of forest are harvested or eliminated annually through deforestation, insect damage, disease and other causes. Thus a total global loss of almost fifty million hectares of destroyed forest feeds its stored carbon into the atmosphere each year and augments global warming.
Value of grasslands. Grasslands also sequesters carbon. As with forests, the rate of sequestration varies. In general the rate achieved by grassland is lower than forests in a comparable ecosystem. The critical difference is that grasslands store sequestered carbon reliably and safely. The total storage of carbon by temperate grassland ecosystems is 60% greater per hectare than the amount stored by temperate forests (243 Mg v 152 Mg), but the amount stored securely underground by grasslands is 150% greater (Climate Policy Watchers, 2019). Grasslands (including heathland and moorland) store 97% of its sequestered carbon in roots and soil where it is protected from fire, and there is evidence that storage capacity could increase further as temperatures rise with global warming and the concentration of CO2 in the atmosphere is augmented by ongoing global emissions. Apart from wetlands and boreal forest ecosystems, temperate grasslands are notable as the largest store of soil carbon. The carbon stored per hectare (to a depth of one metre) is 25% greater in extensive grassland than that stored by intensive rotational grassland (Ward et al, 2016). Disturbance of soil, which occurs in the growing of arable crops, is a significant cause of carbon emissions and soil carbon stocks are halved when grassland is converted to cropland. Significantly there also is a 10% decline when grassland is converted to forest plantation (Ostle et al, 2009). Those comparisons confirm the value of grassland compared to forestry and also emphasise the value of permanent pasture compared with the unsustainability of current methods of cultivation of crop land (Alderson, 2020).
Although sequestration of carbon has attracted more attention, storage of carbon is a critical factor. The details above regarding comparisons between grasslands and forests can also be applied to wetlands to some degree. Their total storage of carbon per hectare is equivalent to forests, but the proportion they store underground (94%) is similar to temperate grasslands.
Prioritisation of grasslands. Resolution of the question of the relative merits of grassland and forests is obstructed by prejudiced opinions and extremist argument. The UK Committee on Climate Change (CCC) has made several important recommendations, but its proposal that 30% of grassland could be converted to forest cannot be justified as a bald statement. Its application in the context of intensively managed grassland would depend on the need of that land to grow human food crops, which is a different discussion. As it stands the proposal betrays a lack of understanding of the critical value of extensive grassland. Revision of the proposal is essential to clarify that it does not include upland pastures, permanent grassland and moorland. Those areas are the focus of extensive grazing, conservation grazing and wood-pasture which are an integral part of the maintenance of biodiversity and sustainability.
Permanent grassland, heathland and moorland provide a combination of benefits that deserve priority in the formulation of future policy. They provide substantial and secure carbon sinks to combat global warming; they encourage improved biodiversity and associated sustainability; they offer grazing for environmentally-adapted breeds of sheep and cattle which also have heritage value as part of local, regional or national culture (Thwaites, 2019). If grasslands continue to be replaced with forests of serried ranks of Sitka spruce the character of the countryside will be lost, carbon storage will be reduced, food production for a burgeoning population (both national and global) will be compromised, and depletion of biodiversity, including genetic diversity in our native breeds of cattle and sheep, would be severe.
Trees have a role to play. Although their relative importance, expressed most vociferously in the clamour for tree-planting, in projects to reduce global warming and prevent flooding has been over-played, there could be potential for increased use of wood in activities such as boat-building and construction and paper manufacture. The best option for trees may not be forests but rather systems which combine the value of trees and grassland in integrated silvopastoral systems such as open wood-pasture with a scattering of pollarded trees in permanent pasture.
Alderson, L. 2020. The Quest to Conserve Rare Breeds: setting the record straight. CABI publishing, Wallingford.
Climate Policy Watchers. 2019. Carbon stocks in vegetation and top metre of soil. Report modified from: Watson, R.T. et al. 2000. IPCC Special Report on Land Use, Land-Use change and Forestry.
Ostle, NJ, Levy, PE, Evans, CD and Smith, P. 2009. UK land use and soil carbon sequestration. Science Direct: Land Use Policy, Volume 26, Supplement 1, pp 5274-5283
Thwaites, H. 2019. Anarchy or Establishment. Hayloft Publishing
UKCEH, 2020. Land Cover Maps. Retrieved 2020 from https://www.ceh.ac.uk/ukceh-land-cover-maps
Ward, SE, Smart, SM, Quirk, H, Tallowin, JRB, Mortimer, SR, Shiel, RS, Wilby, A & Bardgatt, RD. 2016. Legacy effects of grassland management on soil carbon to depth. Global Change Biology. Doi:10.1111/gcb.13246