Mitigating the spread of Ash Dieback
The newswires have been alive over the last few days with the news that Ash Dieback disease has now arrived in the United Kingdom. This devastating disease destroyed 90% of Denmark’s trees and already 100,000 in the UK; it was first discovered in East Anglia in February this year.
So what does it do?
It’s an airborne disease which slowly attacks the leaves and crown of the tree, eventually leading to the death of the tree. Close up it looks like this:
Image courtesy of Forestry Commission
Tree crown damage
Image courtesy of Patrick Pleul/Corbis
How can it be stopped?
The first part of any plan to mitigate invasive species involves trying to understand where the invasive species is, and there are different ways to do this. One can go out and perform surveys on all the Forests in the UK, as well as solicit the help of the local public to report diseased trees when they see them. This concept of crowd sourcing has exploded in recent years with the advent of GPS hand held devices and improved mapping technology, but the idea has been around for a while. The success of Open Street Map’s data in the Haiti earthquake is well known and we all use Wikipedia to look up all kinds of information. With crowd sourcing in mind, the University of East Anglia created an app both for iPhone and Android called Ashtag
that provides a way for anyone to report diseased trees.
It would be very time consuming to survey all of the forests of the UK by sending arborists out on to the ground; hence the role remote sensing can play. Image analysis solutions can identify this kind of phenomena in a variety of ways, by giving you the ability to find areas that are defoliated, or have foliage that is browned or yellowed. The screenshot below show an example of defoliation classification result in ENVI:
But this is only one of the ways tracking disease in vegetation can be done. Another would be using airborne LIDAR to assess the forest volume or to develop specialized algorithms that analyse specific characteristics and deploy them into image/data analysis solutions.
I’ll discuss capabilities like this in more detail in a follow up post, but in the meantime, who else in the blogosphere would like to share their experiences with invasive species? Your comments below are welcome.