THIS is the Castle Howard arboretum as you'll never have seen it before: from the air.
These images were taken from a low-flying aerial drone known as a 'quadcopter' this winter and spring.
The quadcopter is a small remote-controlled aircraft about the size of a footstool which can hover perfectly still using four helicopter-style propeller wings, one mounted at each corner.
That makes it incredibly stable, says Steve Cinderby, of the Stockholm Environment Institute (SEI) at the University of York – so it is ideal for taking low-level aerial photographs using a camera mounted on a swivel joint just beneath the quadcopter's platform.
The SEI has been commissioned to make a complete photographic survey of the arboretum – now known as the Yorkshire Arboretum – from the air.
The images, taken by a fish-eye lens, are now being 'stitched together' using computer software to create a seamless digital map which shows every tree (and even every molehill) in the arboretum's 120 acres.
Volunteers will be going into the arboretum to identify each tree individually at ground level – and, using a "differential GPS surveying system" accurate to within a few centimetres, information about the trees will then be transferred onto the digital map made up of aerial photographs.
Arboretum staff will then, using the map, be quickly able to find exactly where each tree of every species in the arboretum is, says Mr Cinderby, the SEI's deputy director.
The arboretum includes thousands of trees from temperate regions all over the world, including Chile, Europe, the Far East and Australasia.
Many are 'reserve' trees for Kew Gardens, in case rare trees there are damaged or affected by disease.
John Grimshaw, the arboretum's director, said the digital map would be a hugely useful management tool, enabling arboretum staff and visitors to pinpoint exactly where in the grounds trees of a particular species were.
"Or we could ask where are all the tree we planted in 1982 – there are all sorts of things we can do with it," he said.
For the SEI, meanwhile, the arboretum project is a chance to test the capability of the quadcopter for doing aerial surveys.
"By putting different sensors on the platform there is the possibility to gather data for a wide range of environmental issues," Mr Cinderby says.
Camera equipment sensitive to certain wavelengths of light, for example, would enable the quadcopter to be used to carry out rapid aerial surveys to look for evidence of disease in local woodland - whether in ash, as a result of ash dieback, or in larch as a result of infestation by the phytophthora ramorum fungus.
Mount pollution sensors, meanwhile, and the quadcopter could be used to create detailed maps from the air of pollution hotspots in a city such as York, Mr Cinderby says.
With thermal sensors fitted, it could even be used to survey properties from the air during winter, to identify homes which were poorly insulated and so leaking heat. They could then be targeted with energy efficiency advice.
It is quite noisy, Mr Cinderby admits – it sounds like a swarm of angry bees when in flight – and given the sensitivity of people to being 'spied on' by cameras, there is a need for legislation to govern the proper use of such equipment.
When they were using it at the arboretum, most people were simply fascinated, however. "A few people were more cautious and suspicious until I explained the purpose of what we were doing. But most people want to learn how it works, how much it costs - and where they can buy one."
The Yorkshire Arboretum is open seven days a week throughout the summer, from 10am to 4pm weekdays and from 10am-6pm weekends. Entry £6 adults, £3 12-16-year-olds, under 12s free.