Tree Mapping to Support Reserve Management
Informing reserve management decisions through high resolution imagery.
Dr Chloe Barnes
Head of Remote Sensing at 2Excel Geo
Chloe joined the 2Excel Geo team in 2017, following the completion of her PhD in Remote Sensing. She is a domain expert in tree disease detection using spectral imaging and LiDAR techniques from airborne platforms and is an experienced data analyst.
High-resolution imagery collected from aircraft can provide detailed information that allows individual tree crowns within the landscape to be identified and mapped.
On the 26th of June 2018, 2Excel Geo collected high resolution imagery for The Lodge RSPB Reserve. The site, located in Sandy, Bedfordshire, was collected over 8 flight lines at an altitude of 1000m.
The imagery was processed using photogrammetric techniques to produce a digital surface model for the reserve. This information was subsequently used to identify individual tree canopies and calculate tree heights (Figure 1). To find out more about how this process works please see the ‘Finding the Trees in the Forest’ article.
Following the individual tree mapping, single tree canopy outlines (or polygons) were provided to reserve managers.
In many cases, a basic understanding of woodland cover derived from the tree map can be a useful starting point for quantifying tree stock and densities reserves. Introducing information about tree height from the map can then assist in the assessment of woodland mix and age structure
Figure 1
Tree map with tree heights from a section of The Lodge RSPB Reserve
Figure 1
Tree map with tree heights from a section of The Lodge RSPB Reserve
Updates of reserve tree mapping in future years could also be a vital means ‘to record broad changes in the habitats over time’ and monitor ‘regeneration following management’.
In addition, understanding changes in tree cover is also important to quantify the impacts of tree disease such as ash dieback. Using the mapping to track where and how much of the canopy we have lost and how those gaps respond
One specific use case for tree mapping in species conservation would be to assess tree cover in areas subject to beaver re-introduction.
It would be good to be able to estimate tree cover now to compare it with tree cover in a few years time after beavers have been at work.
Information regarding the location, density and height of trees can be important for informed land management. Remote sensing platforms provide a means of quickly deriving this information to support conservation planning and monitoring.
