MEMBRA: Understanding Memory of UK Treescapes for Better Resilience and Adaptation

MEMBRA responds directly to Theme 3 of the call: "Resilience of UK Treescapes to global change", whilst also covering aspects of Theme 1 and 2.

Memory is the acquisition, retention and transmission of information guiding future action. It is used habitually by humans (e.g. in reading this Summary), is easily detectable in the behaviour of animals, and is the basis of machine-learning computer codes. Is it meaningful to talk of the 'memory of trees'? Science has established that plants can write and access a record of prior stress, making the phrase as meaningful to discuss as the selfishness of genes or the (artificial) intelligence of a machine. Writers and artists have responded creatively to how this new knowledge is altering our relationship with trees - perhaps most notably Richard Powers in the Pulitzer Prize winning novel 'The Overstory'. This co-ownership of the idea of tree memory across science and the Arts makes it particularly suited to the Future of UK Treescapes programme. Processes related to plant memory may be fundamental in allowing treescapes to swiftly adapt and therefore survive and thrive under the rapid environmental shifts of the Anthropocene.

The imprinting of memory in plants mostly happens by altering its epigenetic signature: i.e., changes that occur to the DNA that alter the activity of some genes, but that do not involve changes of the DNA sequence itself. The specific epigenetic marks known to be responsible for long-term memory, including transgenerational resistance, arise from the replacement of hydrogen atoms by methyl groups in the DNA base, cytosine. Very recently, a study in poplar has demonstrated transgenerational maintenance of epigenetic marks, pointing to a potential transmission of memory in long-lived perennial plants. However, whether long-lived plants can acquire, retain, and transmit memory from stress remains unknown. MEMBRA will study epigenetic changes and transgenerational memory as a result of stress in key tree species present in UK treescapes. Different abiotic (i.e. drought, frost, elevated CO2) and biotic stresses (i.e. insect infestation and disease) have been selected on the basis of our preliminary data showing that they alter important traits, e.g. growth, within UK treescapes. This project will also take into consideration past experiences. Trees have marks of past interactions with the environment recorded into their wood as they grow. We will analyse tree rings and isotope markers of drought stress to visualise a complete lifetime picture of the responses of trees to their past environment. The combination of ecology, tree rings and molecular techniques will allow us to assess the ability of previous stresses in improving the resilience of UK treescapes.

The understanding of stress memory in trees opens new paths to consider, e.g. the re-conceptualisation of environmental ethics and even tree consciousness. MEMBRA will collate information on how memory has been represented as a characteristic of trees. The project will study how this alters our understanding of the evolution and resilience of treescapes, how a consideration and appreciation of memory in trees can foster moral understanding of treescapes, and how the resulting ethical valuing of trees challenges a utilitarian and monetised 'ecosystem services' valuation of treescapes.

MEMBRA will provide the tools to identify the species and populations that will result in better resilience and adaptation and that will therefore be used in conservation and planting strategies. With the knowledge on how a consideration and appreciation of memory in trees can foster moral understanding of trees, we will identify and use new language to incorporate the concept of tree memory into policy-based initiatives. The final convergence of the results of MEMBRA will feed into policy development and the flourishing of the first stages of a memory-inspired intentional forest: the MEMBRA Treescape.