FRUIT and nuts on native British trees are ripening on average 18 days earlier than they were a decade ago, data from the Woodland Trust has shown.
Observations from Nature’s Calendar, run by the Woodland Trust, in which members of the public record the timing of natural events, have suggested that the changing climate is altering the fruiting patterns of a range of trees.
The trend of earlier ripening has been seen across 12 different species, with acorns in Scotland ripening 18 days earlier than in the period 2000-2002, beech nuts 21 days earlier and rowan berries almost a month before they did a decade ago.
Experts believe the shift is down to the trees flowering earlier in the face of warmer springs.
Professor Tim Sparks, nature adviser for the Woodland Trust, said: “There is a suggestion that the average ripening dates have some correlation with mean temperatures recorded for April, so we presume that the link is through earlier flowering leading to earlier ripening.
“However, to see such a uniform advance across so many species is most unusual and we need many years’ more data from the public to try to better understand the reasons for these changes.”
The trust also said it had data showing that trees including oak, rowan and hazel had all produced increased crops of fruit and nuts over the past ten years.
And 2011, the trust said, was likely to be a “mast year” – a bumper crop – for both beech and oak, possibly because of the early, hot spring the country witnessed this year.
This spring was the earliest since 2000, according to observations recorded for the Woodland Trust, with some events occurring earlier than in any year for which information is held – in some cases dating back to 1891.
The Woodland Trust said the changes to fruiting may mean wildlife will have access to more food earlier, but the reserves could then be depleted earlier in the winter.
The charity is urging people to plant a million native trees in gardens as part of its Jubilee Woods project marking the Queen’s Diamond Jubilee to help provide benefits for wildlife.
James Reynolds, a spokesman for RSPB Scotland, said that the statistics were a “cause for concern”.
“It is worrying that such a marked shift in fruiting period can occur over such a relatively short space of time, and demonstrates that the phenomenon of climate change is very real and is directly impacting out environment,” he said.
“Whilst perhaps not as immediately critical as a very tight food peak shifting when birds are raising their young, it is still nevertheless a cause for concern.”
Louise Burfitt-Dons, campaign director for Global Warming Alliance, said that they were not surprised by the results of the results of the survey: “[They are] a further warning that the relentless rise in CO2 emissions is incrementally raising planetary temperatures, increasing water vapour in the atmosphere with a commensurate rise in rainfall, and ever stronger wind patterns randomly occurring across the globe.”