Michael Sander explains why mapping trees and vegetation gives grounds managers the data to determine whether these are natural assets or possible threats.
05 February 2018 | Michael Sander
Fallen trees can damage property, wreck electricity supply and, in rare cases, injure or kill people. This isn't a smear campaign against forests, but rather a reminder of how vegetation, when left unchecked, can send ground managers into damage-control mode.
Determine the threat
The answer is to analyse trees and vegetation surrounding properties to determine the threat they pose. But it is often too expensive. This can lead to ground managers reacting to unplanned maintenance rather than prepare for it.
ArborFlight uses airborne tree and vegetation analysis to scan large geographical areas. Its experience of surveying millions of trees worldwide shows that typically only 2.38 per cent of trees surveyed require immediate remediation work.
Airborne surveys can help find the 'needle in a haystack', looking at large areas of trees and vegetation quickly to pinpoint any dead or dying trees, or trees that are showing signs of stress. Ground surveyors can then be directed to these problem trees.
Where a tree is hazardous owing to decay or structural weakness, and shows signs of this, the occupier of the land on which it stands is normally liable under UK law for any personal injury or damage that it causes. Occupiers and landowners have a liability of risk that needs to be managed.
This innovation allows landowners and managers of multiple estates to step towards compliance quickly in comparison with standard ground-based surveying.
By attaching hyperspectral and multispectral cameras to a fixed-wing aeroplane or helicopter, data can be gathered and analysed from more than 20,000 trees a day compared with ground surveys that can typically only survey 100 to 200 trees in the same time. The height, canopy cover and GPS location of trees and vegetation can be analysed, as well as their distance from infrastructure.
Using this data, which is managed through tree-management software, managers can assess the condition of the trees and vegetation and decide on remedial action. This means that budgets can be managed and jobs can even be dispatched to contractors for remedial work.
Compared with Lidar (light detection and ranging), this approach is more sensitive to subtle changes. Lidar, for example, cannot determine if a tree is going chlorotic, producing anthocyanins or losing turgor as an early response to stress, as it measures structure through a 3D point cloud.
Using narrow spectral bands allows for advanced detection and the big advantage of this approach is it can be used as an early warning system - greatly increasing the chances to manage pests and diseases.
Michael Sander is managing director at tree and vegetation management specialist ArborFlight