Topcon helps National Trust woodland restoration take wing

Called the ‘Rise of Northwood’, the scheme will see more than 75 hectares of former farmland near Slindon, West Sussex, returned to woodland. Much of the original Northwood forest – dating back to the Middle Ages – was cut down during the First World War to provide timber for coal mine props and trench reinforcements, and then ploughed during the Second World War to help increase food production.

The National Trust acquired the agricultural land in 1950, as part of the Slindon Estate, with tenants farming the fields. In 2013, the management of the Northwood fields was returned to the Trust and with funding from a bequest, the organisation decided to restore the land to woodland.

Hannah Woodhouse, Northwood project ranger for the National Trust, explained: “As well as restoring a naturally wooded landscape, this project will also improve local biodiversity and provide greater visitor access. The additional tree cover the change of land management will help reduce the impact of local flooding by slowing surface water run-off, and cut the risk of soil erosion.”

Work began in 2014, with a team of volunteers from the local community seeding the ground and planting more than 13,000 tree saplings in one field, with natural colonisation allowed elsewhere. Before planting, the National Trust wanted to carry out initial aerial imaging of the land to provide a baseline to measure the growth of the new woodland. Regular monitoring has to be undertaken throughout the project not only to keep track of the restoration, but to protect several sites of archaeological interest on the land – some prehistoric.

Hannah continued: “We wanted to carry out aerial, rather than terrestrial, surveying to protect the seedlings and newly-planted saplings from being damaged by people passing through the planted areas. Topcon offered us a system that could provide accurate information we needed to help us protect the archaeological sites and identify any areas of woodland in need of additional care and attention.”

Topcon’s unmanned aerial system (UAS), the Sirius Pro, meant the National Trust could get high-resolution images of the developing woodland. The fixed-wing UAS features a built-in navigation system (RTK GPS) which allows it to relay the precise location of the area being mapped, and eliminates the need for ground control points, allowing Northwood to be surveyed without people disturbing the newly-planted trees.

“The quality of the images from the Sirius Pro is so good that you can zoom in on a particular tree and follow its growth over time,” added Hannah.

Two years into the project and the restoration of Northwood is progressing as planned. Planting in additional fields on the site began early 2016, and cattle are due to be introduced into areas designated as wood pasture in the next five years. Northwood is expected to be fully open to the public by 2022.

Mat Kellett, mapping & OEM sales manager at Topcon, concluded: “Restoring woodland is hard work. Careful planning is needed in the early stages, followed by constant monitoring to make sure both the plants and the animals are healthy, and to ensure the surrounding countryside is not adversely affected by the changes in the local environment. Northwood is a great example of how UAS technology can help in the environmental and heritage sector, providing a way to map large areas quickly and without disturbing the wildlife.”

For more information on Topcon’s surveying equipment, please visit http://www.topconpositioning.co.uk/. For more information on the National Trust’s Northwood project, visit www.nationaltrust.org.uk/slindon-estate..