Aerial maps reveal successful woodland expansion in Scotland's Cairngorms
A University of Cambridge–led team has used aerial surveys across a huge swath of the Cairngorms National Park in Scotland to create detailed 3D maps that show the beginnings of large-scale recovery of native woodland.
The maps document a success story for the Cairngorms Connect nature restoration partnership: Young trees are spreading naturally into areas where woodlands have been missing for centuries, following a landscape-scale approach to deer management across the partnership's 60,000 hectares.
From a light aircraft flying 600 m (2,000 feet) above the ground, a laser-scanning technology known as LiDAR collected the data used by the Cambridge team. Their new AI-supported method of analyzing the data revealed more than 6 million individual trees across the 569 km2 survey area, as well as the exact height of every tree.
The results show that 2.65 million trees—just over 40% of those surveyed—were under 5 meters (16 feet) tall. These small, regenerating trees grow mostly near the edges of existing forests, where seeds are most likely to fall—but some new trees were found growing more than half a kilometer from the forest edge.
The maps also show that habitat type matters for tree regeneration: Fewer new trees had established in boggy areas than in dry heathlands.
"The ability to map regenerating trees so precisely, at such a huge scale, is a breakthrough for monitoring nature restoration at a landscape scale. It means we can effectively map young trees, assess whether restoration targets are being met, and inform future restoration work," said Dr. Aland Chan of the University of Cambridge's Center for Landscape Regeneration, who co-led the work.
The team used a new method to visualize the data from laser scans made from a plane flown across a huge swathe of the Cairngorms National Park in Scotland. The resulting images show each tree—and its height—revealing millions of young trees and the beginnings of large-scale recovery of native woodland. Credit: University of Cambridge
Point measurements on the ground validated the accuracy of the team's results: millions of young trees have naturally established in the Cairngorms National Park following an increase in deer culling. Credit: University of Cambridge
The team's new method of analyzing the LiDAR data revealed over six million individual trees across the 569km2 survey area, as well as the exact height of every tree. The numbers here represent tree height. Credit: University of Cambridge