Taking advantage of the good weather we set up on the grass outside the football club where anyone visiting Chipping Sodbury Ridings would see us. We had displays about the different strands in the project, and illustrated some of the different ways in which trees contribute to the natural environment, the economy and human health. For children we had a range of tree-themed activities.
Photograph by Margarida Sardo
The day started with Sarah showing the rest of the team how trees are measured. The large horse chestnut tree in front of the football club was repeatedly measured to ensure that everyone was confident with the methods we were using. Height was measured using a clinometer. The clinometer is held at arm’s length and the sight guides lined up with the top of the tree, the angle between a line horizontal to the observer’s eye and a line from the observer’s eye to the top of the tree is measured, the height of the observer’s eye and distance from the tree are also recorded. To simplify the calculation we fixed the angle at 45˚; distance from the tree plus height to the observer’s eye is then equal to the height of the tree. Girth was measured at 1.3m above ground, canopy spread North, South, East and West and the height at which the canopy started.
More detail about how to measure trees is on our website; anyone is welcome to contribute data.
http://dryproject.co.uk/about-the-project/citizen-science/urban-and-rural-trees/
Photograph by Sarah Ayling
Tree positions will be marked on our on-line map and the information recorded used to estimate the benefit to the macro-economy that the trees provide through, for example, water cycling, shade provision, and removal of atmospheric pollutants. This approach, known as ecosystem services, is explained in a short YouTube video by Mark Everard.
https://www.youtube.com/watch?v=D6luBEJfi3s
During the day we were able to measure about 25 trees, at various locations around The Ridings. The Ridings is an excellent location for collecting information about trees because there is an active conservation group and the date of planting is known for many trees.
17 August turned out to be one of the hottest days of the summer with a midday temperature close to 35˚C. There had been little measurable rain in the preceding two weeks. The exceptionally hot dry weather may have deterred some people but those who came told Liz some fascinating stories about past droughts, and the problems that alternating periods of very wet and very dry weather can cause. Measuring in the shade of the woodland areas was definitely more enjoyable that measuring trees around the carpark; a practical demonstration of the effect trees have on the microclimate.
If you belong to a local conservation or woodland management group within the Bristol Frome, Upper Don or Eden catchments and would like us to come and hold a tree measuring session with you please contact us. Email: DRY@uwe.ac.uk Telephone: +44 (0)117 32 87024