Recent advances in unmanned aerial vehicles (UAVs), also known as drones, have made them affordable and easily accessible for deployment as “near” remote sensing platforms. By attaching different sensors, it is possible to gather a wide range of environmental data – air pollution, land cover surveying, wildlife recording, heat mapping, etc.

Steve Cinderby explains how he came to deploy a drone in the Yorkshire Arboretum, and he discusses drones’ potential in environmental research – as well as the ethical issues they raise.

Q: What is your project about?
A: The Yorkshire Arboretum has tagged all its trees with labels that link to a digital database. Unfortunately this doesn’t tell people where they are in the site. The arboretum, which is an outpost for Kew Gardens, asked us to help develop a way of identifying all the trees locations using a low-cost method. The goal is to provide the staff with a detailed digital map that links the description of every tree to its location, and will be editable and updateable. We will also be training the staff in the online geographic information system we create and showing how they can use the data in their work.

The Arboretum has more than 7,000 trees from temperate regions around the world
The Arboretum has more than 7,000 trees from temperate regions around the world. Click to enlarge.

Q: Why use a drone?
A: It was a low-cost way to develop detailed air photography for the Arboretum site. We are using the latest version of the DJi Phantom quadcopter ; this is an off-the-shelf solution that is designed to be simple and easy to use – but it is definitely not a toy and is a very capable piece of equipment. The quadcopter is designed to take a rugged GoPro camera that can record video and stills in a moveable mount, so you can adjust your photos in flight. The GoPro can link through WiFi to a tablet to control and view the images. We can also add a direct live feed to a screen or goggles to view in real time the images being captured.

The Phantom can also be upgraded to fly pre-specified transects using its onboard GPS. At the moment we aren’t doing this and fly the quadcopter manually, so we are always in direct control.

To accurately locate the images on the ground, we have also collected some control points using a differential GPS surveying system (see picture below). This is highly accurate down to a few centimetres – as opposed to handheld GPS, which are accurate to within a few metres.

Once we have the images, we will ask volunteers to collect the tree tag information and link it to the photographs by doing field surveys. This will be quite time-consuming – but it is a lovely location with a great tea shop!

Cinderby field research
Steve Cinderby uses differential GPS to accurately locate trees. Click to enlarge.

Q: How have visitors to the arboretum reacted to the drone?
Public reaction has been interesting. Most people are fascinated and want to learn how it works, how much it costs, and where they can buy one. A few people were more cautious and suspicious until I explained the purpose of what we were doing. The only slight criticisms have been over the noise when it is flying at low level in the arboretum, since people come here for tranquillity.

Whether this enthusiasm would hold for other places and purposes is hard to judge from our existing experience.

Q: What do you see as the potential ethical issues related to the use of drones? How do you see their use evolving, and what other issues could arise?
A: I think the potential for low-cost UAVs for environmental research is quite large. They can collect data in high resolution in areas difficult to survey, for relatively low effort and costs. The platforms are capable of lifting other sensors that could record beyond visible light, such as infrared, to look at green biomass levels. They could be deployed to record areas of rapid environmental change or during specific events to improve our understanding of what is going on.

The challenges are that as these UAVs become more common, the potential for their misuse and consequent public and legislator backlash increases.  If they are seen to be being used for nefarious or inappropriate activities, I think they may require licences – but we will see.

Q: What is the prospect of using drones in other areas of SEI research?
A: I think in specific areas of our research, the potential is high. The data we are generating could be used in a variety of ways. The processed imagery we are capturing includes height data which could be used to identify stocks of above-ground biomass – which equates to carbon. We could survey river height repeatedly to get drainage information and outflow data from catchments. With repeat surveys we could assess changes in carbon under different management regimes. With filters added to the Go-Pro, and other sensors added, we could look at biomass stocks or the heat losses from buildings. We could potentially fly other types of sensor to record pollution levels at different altitudes – all at relatively low cost and when we wanted or needed the data rather than when a satellite or plane was surveying our study area.