The Woodland Trust is urging people to visit their nearest wood and help scientists track the arrival of autumn. The charity has been assessing seasonal change and its effect on trees and plants for 12 years, and this year they hope to enlist 'citizen scientists' to help make a record.
Public records of autumnal indicators this year are universally low compared to the same date last year, say the Trust, indicating that autumn could be later than usual in 2012.
Autumn colour dates vary considerably from year to year as they are affected by temperatures and rainfall; both of these factors also determine the intensity of autumn colour. However autumn as a whole is getting later as warmer temperatures mean that the trees continue to grow for longer.
According to data recorded by the Trust's Nature's Calendar project the benchmark date for the UK's most symbolic tree - the oak - to show the first signs of autumn colour is September 25th, with full tinting appearing by October 30th.
But so far this season there have been 96% fewer records of oak trees' first tint; 81% fewer records of ripe bramble; and only one record of a fieldfare arriving compared to nearly 40 at the same date in 2011.
The charity's VisitWoods website contains details of over 11,000 publicly accessible woods, which people are being encouraged to visit to observe the changes taking place - check out the site to find your nearest woods, and for details of how to record what you see.
Dr Kate Lewthwaite, Nature's Calendar Project Manager, said:
'Autumn is the best time of year to get outdoors and visit one of our many beautiful native woods. People can also do their bit to help us learn when and where autumn is arriving, the information provided is absolutely crucial to us understanding how flora and fauna is adapting to the changing environment. We are particularly keen to receive more records from the public in autumn too.'
In autumn 2011 over 25,000 observations were recorded by people across the UK. Without these public observations the Trust will not be able to assess the effects of the changing climate on our native trees, they say.