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Are ripe berries a warning for wildlife?

Ripe blackberries have been spotted in July (Credit: WTML/Ben Lee)
Ripe blackberries have been spotted in July (Credit: WTML/Ben Lee)

Wacky weather could mean early berry batches, but browning and weakened trees, warns Woodland Trust.

The Woodland Trust’s Nature’s Calendar project is already receiving records of ripe berries in the current heatwave – but the dry weather could spell danger for this year’s wild fruit crop, and the animals that feed on them.

So far the Trust has received 59 records of blackberries ripening, and six records of rowan berries ripening1. The baseline average for these events is 27 August and 1 September, meaning the earliest sightings this year have come in around two months earlier than this, and about two weeks earlier than our expected date range. The first ripe sloe was also recorded on 12 July (baseline average for this is 19 September). The heatwave could also trigger other changes in UK flora, with tree leaves browning earlier as well.

These early changes in summer scenery could, however, suggest something more sinister. If the hot weather continues, the lack of water could mean that berries may be smaller or drop from trees and shrubs altogether. Migratory birds like fieldfare and redwing (arriving in the UK around October) could be left with less food if the resident wildlife has taken their share first. Furthermore, trees may tint earlier as they try to preserve water and can also be more susceptible to threats such as tree pests and diseases.  

The first ripe sloe has also been recorded (credit: WTML/Ben Lee)
The first ripe sloe has also been recorded (credit: WTML/Ben Lee)

The Trust, therefore, is urging the public to take note of seasonal changes and report them via Nature’s Calendar.

Dr Kate Lewthwaite, citizen science manager for the Woodland Trust, said: “It may be the height of summer, but because of the recent weather, we’re already anticipating signs of autumn. Although we’ve only had a small number of berry records so far, the heatwave will only encourage more fruit to ripen, and leaves on trees may also start to change colour.

“Given the implications this may have for the berry crop and other species in general, we would urge the public to report the first seasonal events they see to Nature’s Calendar.

“Citizen science is vital in informing our view of changing seasons. This year spring suddenly burst forth in April after being subdued by snow in March – now, with this heatwave, it will be interesting to see how other seasonal timings and species are affected for the rest of 2018.”

The Beast from the East also triggered a surge in records, with 4,750 spring events being reported in April when the snow and ice subsided (compared to collective 3,227 records between January and March).

Nature’s Calendar is a continuation of seasonal recordings which date back to the 18th century. By recording the timings of natural phenomena, thousands of people have enabled Nature’s Calendar to become the leading survey into how climate change is affecting UK plants and wildlife.

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Notes to editors

For further information contact the Woodland Trust press office on 01476 581121 or email

The Woodland Trust is the largest woodland conservation charity in the UK. It has over 500,000 supporters. It wants to see a UK rich in native woods and trees for people and wildlife.

The Trust has three key aims:  i) protect ancient woodland which is rare, unique and irreplaceable, ii) restoration of damaged ancient woodland, bringing precious pieces of our natural history back to life, iii) plant native trees and woods with the aim of creating resilient landscapes for people and wildlife.

Established in 1972, the Woodland Trust now has over 1,000 sites in its care covering over 22,500 hectares. Access to its woods is free.

1. 2001 is used as a benchmark year as spring weather conditions closely reflected the 30 year average supplied by the Met Office (spring weather determines berry ripening, despite being an autumn event). You can download an excel spreadsheet of observations here and view a map of records to date here.