Rachel Abernethy continued: “The really interesting thing about this research is the annual variation in timing of budburst. It is important to realise that seventeen years (2000 to 2016) is a very short time when studying climate, and annual fluctuations will be evident.
"For example, we had a colder spring in 2016 than previous years and this resulted in a delay in budburst of many tree species. Understanding how nature responds to a changing climate – whether it is warmer or colder from one year to the next – is important. Hopefully this work can contribute to long-term phenological studies in the future.”
Judith Garforth, Woodland Trust citizen science officer, said: “Citizen science is invaluable when recording data which identifies UK-wide trends over a long period of time.
"Our Nature’s Calendar volunteers have recorded literally millions of pieces of information since the year 2000 and without their support we would understand far less about the impacts of weather and climate change on wildlife in the UK.”
Professor Tim Sparks, University of Coventry, added: “We know that most trees respond to increased temperature by leafing earlier in spring. This work confirms that this simple fact is complicated by differences between tree species and between regions"
Dr Debbie Hemming, of the Met Office Hadley Centre, leads a group studying the interactions between vegetation and climate. She said: “Collaboration between phenology and climate experts has enabled better understanding of the sensitivity of prominent UK tree species to climate variability and climate change.
"This knowledge can be used to inform appropriate management strategies that support healthy UK trees and woodlands into the future.”