A new study from some of the UK’s top ecological research institutes, including The James Hutton Institute, has highlighted the importance of thinking about more than just species diversity to improve the resilience of the nation’s forests to climate change, disease, and other future threats.
Genetic variation within species and epigenetic changes in individual trees both have lasting impacts on responses to future stresses like drought and disease.
Genetic diversity refers to the variety of DNA differences found among individuals within a tree species. It is due to genetic differences among parents and new mutations.
Epigenetics describes chemical changes to DNA that affect how genes are expressed. One example of an epigenetic change in trees is bud burst (the swelling and opening of buds to release new leaves, shoots, or flowers), which depends on the temperatures a tree has experienced. Moreover, epigenetic changes can be understood as a memory. When the memory relates to a stress (e.g. drought or disease) it can inform the tree’s response to stresses in the future.
The technical paper in the Quarterly Journal of Forestry, which was written by experts from The James Hutton Institute, the UK Centre for Ecology & Hydrology (UKCEH), the University of Birmingham, Forest Research, and the Woodland Trust, examined ways to diversify the nation’s forests and increase their resilience to climate change, disease, and other threats.
While genetic diversity is increasingly being considered in forest resilience, epigenetics is a rapidly growing area of research. The work carried out by researchers showed that greater attention to both genetics and epigenetics is needed alongside tree species diversity when considering diversification of woods and forests.
In addition to the importance of genetic and epigenetic diversity, the paper’s authors found that diversification does not always guarantee greater resilience, and there is ‘no one right answer’ to the question of diversification. They advise taking a range of diversification approaches across different sites to maximise resilience. For example, within one catchment some sites might have low species diversity but high within-species genetic diversity while other sites might have high species diversity but lower within-species genetic diversity. Given the uncertainties over future climate and diseases, the authors warn that failure is likely to be a part of the process.
They also suggest identifying management practices that benefit all levels of diversity. Forestry management – such as silvicultural practices that promote natural tree colonisation and natural tree regeneration, with tree seedlings establishing from mother trees – has the potential to benefit three levels of diversity. Trees colonising new ground increases species diversity and, genetically, it allows population to track changing environment as it selects individuals best adapted to local conditions.
Titled Species, genes and epigenetics: how dimensions of diversity interact for forest resilience, the paper was published as part of the Tree of Knowledge project, which is funded by the UK Research and Innovation Natural Environment Research Council’s ‘Future of UK Treescapes’ programme.
Dr Stuart Smith, a senior researcher at the Hutton and lead author of the paper, said, “When thinking about diversification within our woods and forests, we often only think about tree species diversity, or if we do think about genetic or even epigenetic effects, we think about these different types of diversity in isolation.
“The novelty of this work is that we have tried to think about all these different types of diversity and how they might interact.
“These findings show the importance of considering all aspects of diversity – species, genetic and epigenetic – when trying to improve the resilience of our forests.”
The full paper is available here: https://rfs.org.uk/smith-et-al-october-2025-qjf/
The authors reached their conclusions after examining existing research on woodland diversity and resilience, including three previous Future of UK Treescapes projects: DiversiTree, which examines tree species diversity, newLEAF, which investigates how trees adapt to environmental change and genetic diversity, and MEMBRA, which explores epigenetic effects and how past stresses are recorded in a tree’s ‘memory’.
