Woodland coverage in England was at its lowest in the early 20th century, when it stood at around 5 per cent of the country. Tree cover increased throughout the 20th century, mainly because of post-1918 coniferous plantations, and included the replanting of areas of former native woodland. At present, woodland covers 13 per cent of the UK (10 per cent in England), though this is still less than half the European average of 30 per cent.
The Government has made a commitment to increase the woodland coverage of England from 10 to 12 per cent by 2060. The benefits of doing so are clear: woodland can deliver social, environmental and economic benefits to society. It also helps to safeguard clean water and to manage water-flow in areas at risk of flooding. It can improve biodiversity and is a source of renewable energy.
Areas targeted for the planting of new woodland are likely to be away from the most productive farmland, on poorer soils and in areas of permanent pasture; often these are in uplands or on upland fringes. In these areas, where farm incomes are often relatively low, the planting of woodland can help diversify the rural economy.
The recent plans for a Northern Forest, with up to 50 million trees running in a wide band from Liverpool to Hull, fits this description; much of the area is centred on the M62, and runs through the moors and hills of the Pennines.
Many such less productive agricultural areas, however, have considerable archaeological potential, with good preservation of historic landscape features, earthworks and below-ground remains. Woodland planting schemes may, therefore, have a significant impact on the historic environment as well as on the character of the historic landscape.
In 2016, Historic England commissioned the McCord Centre for Landscape at Newcastle University to carry out the Woodland Futures project. The project, which was completed in 2018, examined ways of measuring the impact of woodland expansion on the historic environment, as well as how landscapes with a rich historic environment can offer opportunities for new woodland.
The project thus helped to identify ways in which heritage-related concerns could inform and benefit woodland planting schemes. Areas potentially suitable for transformation through woodland expansion were identified, along with those most sensitive to change.
The project’s key outputs are a series of statements on the potential for woodland expansion in each of Natural England’s National Character Areas (NCAs); a sensitivity map of England, which plots the capacity for woodland planting across the country; and an assessment framework to help those planning woodland planting schemes to effectively consider the historic environment when they do so.
Creating the national maps
To create the sensitivity map, a series of national historic and natural environment datasets were plotted onto a grid. The datasets chosen had to be available for the whole of England, and have well-defined attributes that allowed a consistent scoring system for woodland potential to be developed.
As the intention was to assess what opportunities for woodland planting were available as well as the possible impact of such planting on the historic environment, and to do so both for individual sites and for entire landscapes, historic and natural environment attributes were compared.
Many of the datasets involved were highly complex, and comprised numerous areas that were very small in size. It would have been a lengthy and difficult process to produce countrywide coverage at a large scale, and the very small polygons that resulted would have been inappropriate for use at a regional or national level. It was thus decided that a grid of 1 kilometre squares was most appropriate. The squares were scored for each of the natural and historic environmental attributes indicated by the data. A total score for all attributes in each square was then calculated. This score thus indicated the potential for a given grid square to absorb new woodland, with higher scores indicating greater potential. The higher the score, the darker the shade used on the resulting map.
The darkest squares with the highest potential for the planting of new woodland are those with a score equal to or greater than 10. Having produced a national map, it became possible to also select areas in which clusters of grid squares of high and low potential lay.
Four historic environment attributes were mapped, all relating to national or international designations: registered parks and gardens, scheduled monuments, registered battlefields and World Heritage Sites. Grid squares containing such sites were scored 0 (least able to absorb new woodland), while all other squares were scored 1.
The datasets were chosen because they were readily available and provided national coverage. Other datasets were either unavailable to the project or did not provide consistent coverage across England. The original intention, for example, was to map historic environment data as recorded on the Selected Heritage Inventory for Natural England database, but this was not available during the mapping phase of the project.
National Historic Landscape Characterisation data was also unavailable, as that project was incomplete. It would be possible to refine the mapping at a later date by incorporating such datasets.
The results were analysed against each of the 159 of Natural England’s NCAs. These divide the country into distinct areas, each defined by a combination of characteristics, described in a character profile for each area. These characteristics include landscape, biodiversity, geodiversity, history and cultural and economic activity. The NCAs are used by governmental and non-governmental bodies, particularly Natural England itself, to inform a range of activities and to help monitor landscape change, including forest and woodland plans and strategies.
The overall potential for each NCA to absorb new woodland was estimated by calculating the percentage it contained of areas given a high score in the kilometre-square assessment. If the locations considered to have high potential for new woodland covered less than 14 per cent of the total area of an NCA , then that NCA was considered to have an overall low potential for new woodland; those with a score of between 14 per cent and 20 per cent were considered to have medium potential, and scores of greater than 20 per cent were considered to have high potential.
For most NCAs, the potential for woodland expansion fits well with the environmental opportunities for the area already outlined by Natural England in their NCA profiles. For very small NCAs, such as Lundy and the Isle of Portland, the mapping grid was too small in scale to provide a statistically valid result. Caution should be taken, therefore, when using the woodland potential map for these areas, and more emphasis should be placed on Natural England’s written report for each NCA.
The potential for woodland expansion
As might be expected, the areas with the fewest opportunities for woodland expansion are urban: they include London, Birmingham, Merseyside, Manchester, the former industrial towns and cities of the Pennines, and coastal towns.
Other areas with low potential are clustered in the east of England, in a wide band from the Wash to London which represents some of the most valuable areas of arable agriculture. Areas of high potential for new woodland are scattered more evenly across the country, but include noticeable clusters along the Pennine fringes, in Norfolk and in a wide band stretching across south-eastern England from the Weald to Hampshire.
Overall, 10 NCAs had attributes that indicated a high potential for new woodland. They are:
- Cheshire Sandstone Ridge
- High Weald
- Lincolnshire Coast and Marshes
- Quantock Hills
- Morecambe Bay Limestones
- Morecambe Coast and Lune Estuary
- New Forest
- Solway Basin
- Somerset Levels and Moors
Of these 10 NCAs, only Lincolnshire Coast and Marshes is an area dominated by arable agriculture.
Both High Weald and New Forest are areas that are already very well-wooded.
Solway Basin, a low-lying area in northern Cumbria, currently has very low levels of woodland, but the author’s own research indicates that the area was well-wooded in the medieval period.
The high score for Lundy is an anomalous result, reflecting the small size of the island in relation to the 1 kilometre grid used for the initial mapping exercise. There is no significant woodland on the island, and given its high historic and nature conservation value as an open landscape, new woodland would not be appropriate here.
The assumption that upland and upland fringe areas are the most suitable for new woodland was not necessarily borne out by the project, reflecting the high value of their existing historic and natural environments.
The project report and assessment framework, the statement of woodland potential for each NCA, and the underlying GIS layers have all been made publicly accessible through the Archaeology Data Service, where the information is available to download.
About the Author
Dr Caron Newman MCIfA FSA
Research Associate of the McCord Centre for Landscape, Newcastle University
Caron's PhD research was on the medieval and post-medieval landscape of Cumbria. She worked in north-west England for many years, both in commercial archaeology and for Historic England’s predecessor English Heritage. Her previous projects include the historic landscape characterisations for Cumbria and the Lake District National Park, the Extensive Urban Survey for Lancashire and the Irish Sea region of the Historic Seascapes project.
Forestry Commission 2015 Corporate Plan. Bristol: Forestry Commission
Forestry Commission 2017 Forestry Statistics 2017. Bristol: Forestry Commission
Natural England’s National Character Area Profiles: https://www.gov.uk/government/publications/national-character-area-profiles-data-for-local-decision-making/national-character-area-profiles
Newman, C 2014 ‘Mapping the Medieval and Post Medieval Landscape of Cumbria’. Unpublished PhD thesis, Univ. Newcastle
Newman, C 2018 Woodland Futures. Assessing Impacts of Forestry Strategies on the Historic Environment. Archaeology Data Service.