June 29th, 2010 by Sustainable Guernsey
Jon Stokes of The Tree Council joined Guernsey Tree Wardens to celebrate their third anniversary. He gave an informal talk to the Guernsey Tree Wardens lunch on 29 June. He told them he was a promoter of trees; he gave Guernsey’s Tree Wardens ideas on how to promote trees using marketing techniques to satisfy market demand while at the same time promoting the many benefits of trees.
He mentioned a hot spell in England during which time 4000 school sports days had been cancelled because of the heat. Had trees existed around these sports fields they could have moderated the temperature by providing shade, he said.
Guernsey Tree Warden Coordinator Andrew McCutcheon brought in tree leaves for identification and discussion. He brought Sycamore and London Plane tree leaves. Jon Stokes said that Sycamores are very good at colonising new areas and they do well in salty air. He said that Sycamores are the only trees that grow in the Shetland Islands because of their tolerance of salty air.
Mr. Stokes spoke about the work of the Woodland Trust in the UK and their “More Trees, More Good” campaign. Their goal is to plant 20 million trees a year for the next twenty years to double native woodland cover in the UK. At the moment six million trees are planted in the UK each year.
He mentioned that planting one million trees per year absorbed the equivalent amount of carbon dioxide produced by 80,000 vehicles. (Guernsey has 53,000 registered vehicles.) He said that the jury was still out on the role of tree planting to combat climate change, and that companies of dubious reputation had collected money for tree planting schemes that never materialised.
Mr. Stokes mentioned that the price of carbon was set at about £100 per tonne. Planting trees was “an extremely economic way of capturing carbon” he said, “as the cost of carbon capture by trees was only £50 per tonne.”
The Forestry Commission has produced a comprehensive report on the role of tree planting and carbon capture in “Combating Climate Change – A Role for UK Forests: The Synthesis Report. An Assessment of The Potential of The UK’s Trees and Woodlands to Mitigate and Adapt to Climate Change.”
Jon Stokes was asked about the role of trees in the water cycle. He said “an Olympic-sized swimming pool full of water will provide enough water to support eighty Oak trees for a summer.” Most tree roots are near the surface, which is where trees acquire most of their water. In dry conditions trees may draw water from their tap root. One measured tap root reached a depth of 500 feet but this was exceptional.
Trees transpire the water they draw from the soil. Strong winds can take this moisture away from the area but in still conditions the transpired water will settle in the vicinity. Mr. Stokes mentioned the beneficial role trees played in drawing nutrients from the sub-surface and recycling the nutrients in leaf litter to fertilise the ground.
Time was spent discussing Tree Protection Orders in the UK and in Guernsey. Guernsey had followed the UK in establishing TPOs. Guernsey had already more TPOs than the whole of Cornwall. The number of TPOs varied greatly between English counties.
After lunch Mr. Stokes spoke about identifying trees using simple characteristics. He didn’t necessarily rely on the morphology of leaves to identify trees. To identify trees in Guernsey, for example, Beeches have grey elephant skin-like bark. If the tree bark is grey elephant-skin-like, with stretch marks, it is a Hornbeam. If the tree has white bark it is a birch. If the branches are floppy it is a Silver Birch and if the branches are more butch and held-up it is a Downy birch. Native birches have white bark with flecks. Trees with a very white bark are probably not native.
He recommended the “Reader’s Digest Field Guide to Trees and Shrubs of Britain” for identifying native species.
Mr. Stokes will give a presentation on Treasured Trees at the Frossard Lecture Theatre on 30 June 2010. Tickets (£10 includes The Men of the Trees membership for 2010 / or £5 for MOTT members and Tree Wardens) can be acquired from the Guernsey Ticket Office.