Six Million Trees, One Laser From a Plane

# What was done

# What was found The team counted more than 2.65 million young, newly growing trees within the surveyed area. These saplings represent active natural regeneration across land that has previously experienced wildfire, heavy grazing or recreational pressure, and ongoing climatic shifts.

# Why the method matters Using airborne LiDAR plus AI delivers a repeatable, high-resolution way to monitor restoration across a landscape. One researcher described the approach as "a breakthrough for monitoring nature restoration at a landscape scale." The technique captures structure beneath and within the canopy at a scale that ground surveys alone cannot match, and AI helps process large volumes of returns into meaningful forest metrics.

# How this informs management The Cairngorms is the UK's largest national park, and the mapping connects directly to Cairngorms Connect, a partnership operating with a 200-year restoration horizon. The new map does more than record current conditions: it identifies where the land is already shifting toward forest and where restoration effort would face greater resistance.

• Prioritize support and protection for areas where natural regeneration is already strong, especially drier sites where seedlings are taking hold.

• Use repeat LiDAR surveys to track changes over time and evaluate the effectiveness of management actions against an explicit, landscape-scale baseline.

# The broader context The Cairngorms contain ancient woodland, mountains, and lochs, and they have been shaped by centuries of land use. The mapping provides a contemporary snapshot that links ecological recovery to specific terrain and soil moisture patterns, offering a clearer evidence base for decisions that will unfold over generations rather than seasons.

# What this means for readers interested in restoration The study shows how modern remote sensing combined with machine learning can reveal where nature is already moving toward recovery, and where managers should adapt their tactics. For anyone involved in or supporting long-term restoration, the takeaway is concrete: maps that resolve both tree presence and age classes make it possible to allocate limited resources where they will align with natural tendencies and where they will be most effective.

# Final point The result is a working map that goes beyond inventory. It points out where trees are likely to persist and where active restoration might need to change approach, offering a practical route to manage a large, complex landscape according to observed ecological responses.