Public observations suggest seasonal delay on the cards.
It seems this year’s late spring is having a knock on effect in delaying autumn timings, according to initial observations from the Woodland Trust’s Nature’s Calendar survey, which studies the timings of common seasonal events - Phenology.
2007 was identified as the benchmark average year for autumn due to temperatures being very close to the 30 year average. June 2010 has had relatively sunny weather in comparison to June 2009. June 2009 itself was warm and wet, in fact with 40% more rainfall than average, making it the wettest since 1914.
However, Nature’s Calendar seems to be more complex in autumn than in spring and driven not just by temperature but a range of factors, including rainfall, which varied between extremes from month to month. Indeed, it may be that day-to-day changes in the weather, e.g. early frosts or high wind, have a disproportionate impact on the timing of many autumn events.
Dr Kate Lewthwaite, Nature’s Calendar project manager explained: “What suggests that we could be in for a late autumn is if we look at the average dates of the first observed ripe berries over the past five years we can see that average peaks for this are around 4-6 August. Seeing as the average (the most observations) is around the 4 August for first fruit over the past five years, then considering that we are already at that date and have very few records, it is apparent that autumn could be late this year, just how late we won’t know until the end of the season.”
“For example Bramble fruiting. Flowering was delayed in many species due to the coldest winter for 30 years and this has a knock on effect on fruiting. Last year at this time we had over 1000 observations across the UK peaking on 2 August, with the average 5 August, this year we’ve only had 81 records, all biased towards the south, no further north than Leeds. Looking at that we’re some way behind with lots of unripe fruit still on the bushes, and the best still to come. It’s the same with rowan berries, this year we’ve had 44 compared with 808 last year by this date. With 2 August being the average.”
Keats' "Season of mist and mellow fruitfulness" should begin on September 1 according to Victorian meteorologists, but today’s leaves are not developing their golden autumnal hues until the end of the month.
This year for recordings of beech first leaf tinting (generally the first species to tint) Nature’s Calendar has received just two records so far this year compared to 116 at the same time last year, although we won’t expect to see trees in full tint until late September or early October. And generally oak leaves are not now falling until the end of October, a week later than 30 years ago. In some milder parts of the UK people are reporting that their grass is growing all year round, and conditions permitting, that there is no let up from mowing the lawn.
How you can help:
The benchmark average date of swifts leaving is around 10 August so The Woodland Trust want to hear from people who are still seeing them well into the second half of the month.
This will help them gain further insights and see how wildlife is responding to the changing climate. People can find out more and get involved in real science by visiting the Nature’s Calendar website, www.naturescalendar.org.uk
Feedback received on this subject:
I agree with you there is a delay this year and I can show it in pictures. My test is at the start of the year with the common daffodil. I photograped the first flowers on the 8th March 2009. This year in the same location they flowered on the 18th March. A 10 day delay. Hope this helps.
Mark Williams Portsmouth