Over the past year, our scientists have been involved in a wide variety of research projects, from investigating the cooling benefits of urban trees to developing a remote young-tree detection system using Earth observation data. Here, we summarise a selection of recent projects.
Periods of hot weather, such as those experienced in the summer of 2018, can affect people’s comfort and aggravate existing cardio-respiratory diseases. The UK’s latest Met Office projections suggest that hot summers may become more common by the 2050s. This increase in temperature will be particularly felt in towns and cities where temperatures are already normally higher than in rural areas. The trees and greenspaces within towns and cities can help to provide a solution to this challenge by lowering local temperatures and thereby offering relief to those living and working in these locations. Forest Research has been studying the cooling benefits of urban trees and greenspaces since 2011 and this year have made advances researching this important topic, as outlined in three new publications.
In collaboration with Ricardo Energy & Environment and Uppsala University, Sweden, we have identified which tree characteristics are linked to the greatest cooling and have proposed a methodology that can be used by urban planners and tree managers to compare and select tree species according to their cooling ability. With the University of Reading, we have published information on the evaporative cooling provided by urban forests. Using a mathematical model, we explain that air-conditioning unit energy consumption may fall by up to 13% in Inner London due to the evapotranspiration provided by its trees and that this benefit may lead to annual savings of up to £22 million.
We have also published a comprehensive summary of current knowledge relating to the cooling benefits of urban trees and greenspaces and highlighted current gaps in that knowledge. In this work we have explained the design strategies that can be used to maximise cooling and have emphasised the importance of trees being provided with enough space, water and soil nutrients to grow and be healthy so that they can achieve their cooling potential.
Forest Research is now working towards answering some of the knowledge gaps identified, for example through a study investigating the amount of local-level cooling associated with street trees and how this can help improve the thermal comfort of residents during hot days.
Foresters need to know if young trees have survived their first five years, which is the phase when they become established. This usually requires visiting the planting site, but with tens of thousands of hectares planted and increasing costs, visiting all trees, every year, often proves too expensive. This cost is carried not only by the foresters who plant the trees, but also by those who regulate tree-planting activities, such as the Forestry Commission, Scottish Forestry and Natural Resources Wales. Even recent aerial photography cannot help as the young trees are too small to be visible.
In searching for a solution, our researchers hypothesised that even if the trees are too small to see, maybe we can ‘feel’ them using Synthetic Aperture Radar (SAR). A different technique to using optical data, SAR provides ‘fuzzy’ data on the presence of objects, their size, orientation and texture.
Forest Research realised that the tree-establishment sites change dramatically through the cumulative impact of weed control, cultivation and the establishment of regular lines of young trees. It was also proposed that within any given year there would be a unique change in the relative height between the annual vegetation and the perennial trees, which would leave a unique signature of texture change within the year and over the five years of establishment. This suggestion convinced the Defra Earth Observation Centre of Excellence to fund a proof-of-concept project.
A multi-disciplinary team of Forest Research, Capgemini and Joint Nature Conservation Committee staff was established. The team used SAR data from the Copernicus Earth observation programme along with machine learning to build a model that ‘learned’ the unique texture of young trees and could discern them from the texture of other land uses.
The resultant model proved that SAR and machine learning could not only accurately identify planted areas of over 0.5 hectares, but also proved sensitive enough to discern cultivation prior to planting.
Following this successful trial, we are now planning to implement a SAR young-tree detection system on behalf of the Forestry Commission during the forthcoming year.
Protecting Scotland from new pests and diseases
Plants play essential roles in our lives by underpinning habitats and food webs, helping to characterise our landscapes, regulating our climate and providing raw materials for many economic activities. However, the potential for these contributions to be disrupted by pests and diseases is ever present.
To help address this in Scotland, a new virtual Plant Health Centre has been established, with funding from the Scottish Government. Led by the James Hutton Institute, the Centre brings together a number of organisations, including Forest Research, to coordinate plant health needs and activities across Scotland and provides a Strategic Advice Response Team to enable rapid expert responses to policy questions.
Our new Chief Scientist, Professor Chris Quine, is the Centre’s sector lead for forests and woodlands. Forest Research’s wider expertise from our pathologists, entomologists, social scientists, climate change and spatial scientists will also be drawn upon. Other sector leads are from the Royal Botanic Garden Edinburgh (horticulture and environment) and Scotland’s Rural College (agriculture).
Early work by the new Centre has focused on those plant health threats of highest risk to Scotland. For example, one major threat is Xylella fastidiosa. This bacterial pathogen is able to infect over 200 plant species worldwide and is currently causing major economic losses to olive trees in Italy. Forest Research scientists have been involved in considering how UK contingency plans need to be adapted to particular Scottish conditions by using broad-scale risk mapping, and by making use of recent invertebrate sampling to establish the presence of potential vectors of the disease in woodlands in the Central Belt.
In the coming years the Centre will continue to work closely with a broad range of stakeholders to understand and act on their priorities and concerns. This coordinated approach across sectors should help to improve our monitoring of plant diseases and understanding of the threats, share the best ways of managing risks and impacts and help coordinate emergency responses.
If measures to halt declines in biodiversity are to be effective, significant evidence gaps must be filled. Information on woodland-specialist bat species is scarce because of the difficulties in surveying for bats in these structurally complex environments. This impedes conservation efforts and complicates the design and implementation of woodland management plans aimed at protecting bats and enhancing their habitats. More accurate and cost-effective methods are needed to provide reliable data on the activity levels and distributions of these rare and inconspicuous species.
Over two survey seasons, the Bat Conservation Trust and Forest Research have been working with volunteers across four study areas to pilot methods and technologies for surveying woodlands for bats. The aim was to develop, for the first time, a citizen-science approach that could be carried out at a large enough scale to provide species- and family-specific trend data on bats in woodlands. Data collection was completed in 2018 and the project team has started to synthesise the findings to inform plans for the British Bat Survey, a new monitoring scheme under development by the National Bat Monitoring Programme (NBMP). In addition to comparing the content and quality of the acoustic data recorded using different devices, practical issues such as equipment affordability and user-friendliness are being assessed.
As well as delivering a baseline for long-term monitoring, the species records collected from the survey are being incorporated into a modelling framework for predicting species distributions at national, regional and local scales. This hierarchical approach was developed by Forest Research in 2018 for identifying the factors influencing a species’ habitat suitability, while overcoming some statistical issues common to these types of models.
Once validated, the spatially-explicit outputs can be used to inform targeted woodland- to landscape-scale decision-making and strategies in bat conservation. Forest Research is now working with the Woodland Trust to explore the usefulness of these models for targeting woodland planting in areas to improve bat habitat suitability and connectivity now and in future potential climates.
Forest Research has been working with Forestry Commission Scotland (Forest Enterprise), the Scottish Environment Protection Agency (SEPA) and the Royal Society for the Protection of Birds (RSPB) to study the effects of peatland restoration by deforestation on water quality, hydrological flows and dissolved organic carbon (DOC) transport.
Forests and peatlands both play important roles in the hydrological cycle and in the global warming story; they provide important habitats for a variety of species, regulate water flows, influence water quality and affect carbon storage and release.
In Scotland, climate change concerns are driving removal of non-native coniferous trees from a number of peatland sites, primarily for habitat restoration and protection of soil-carbon stocks. While the importance of restoration is well recognised, its effects on freshwater ecology and water quality, particularly in terms of DOC and nutrient transport, have not been fully investigated. Restoration is often carried out over a relatively short period and at a large scale, leading to concerns about the impact of such a rapid change in forest cover on water quality and ecology. Species such as the freshwater pearl mussel and Atlantic salmon are especially vulnerable to deteriorations in water quality. Moreover, aqueous carbon losses can impact upon drinking water provision due to the link between DOC concentrations and the formation of carcinogenic compounds following water disinfection by chlorination.
Forest Research has set up a number of research sites around Scotland with varying environmental conditions to quantify the carbon and nutrient losses resulting from peatland deforestation. The work will improve our understanding of the effects of peatland restoration on water quality and carbon dynamics and inform whether additional measures are needed to minimise any effects. These would be incorporated into future revisions of the UK Forestry Standard Water Guidelines to the benefit of water consumers and the freshwater environment.
Over the past year, our social and economic researchers have continued investigating the many factors that influence the behaviour of landowners and managers in relation to their management of trees, woods and forests. Land managers play a key role in the delivery of forest ecosystem services, and in responding and adapting to climate change and the threat of various pest and diseases. They can be encouraged in these actions by active woodland management and woodland creation, which is the focus of a number of current government policies.
We carried out an evidence review, ran research workshops and undertook semi-structured interviews in partnership with the Sylva Foundation and Oxford University to explore the barriers land managers experience in changing or adapting their forestry practice for resilience. It is clear that different kinds of woodland managers understand resilience in different ways. This depends on their beliefs and world views, their management objectives, their understanding of forest ecology, and their perceptions of risk and uncertainty.
The results from our research show that changing management practices relies on providing relevant information in a way that impacts owners’ and managers’ beliefs and responds to their concerns about uncertainty. This information can come from a variety of sources and over a period of time, as part of a pathway to change. We found that future knowledge-transfer approaches must tailor advice specifically for different types of woodland manager, such as those that focus on timber production, or multiple objectives, or conservation.
We started a new project in mid-2018 for Defra that is extending our existing research to look specifically at land-manager responses to tree pests and diseases. This time we are working in partnership with the Sylva Foundation, Oxford University, Gloucestershire University and Bangor University. In this research, as well as delving deeper into the beliefs and values that affect managers’ behaviours, we are also looking at how grants and other non-financial incentives, such as partnerships, can help land managers to overcome the barriers they may face in treating, felling and restocking in the face of diseases such as Chalara dieback of ash or Phytophthora in larch. This applied research will help Defra and partners to structure policy options that can support land managers in the coming years.
Populations of red squirrels are being replaced by the non-native grey squirrel, which outcompetes our native red and also carries a virus that is lethal to red squirrels. Forest Research is a partner in the Red Squirrels United project, funded by European LIFE and the National Lottery Heritage Fund, which brings together UK organisations to help protect red squirrels by raising public awareness and engaging volunteers in community groups.
Our role has been to investigate the motivations for, and challenges of, sustainable red squirrel conservation. Our social researchers have engaged with key stakeholders in some of the few areas of the UK where red squirrels remain. This has been facilitated by our partners The Wildlife Trusts, Wildlife Trust for Lancashire, Manchester and North Merseyside, Red Squirrels Trust Wales, Northumberland Wildlife Trust, Ulster Wildlife, The Wildlife Trust of South & West Wales, and Newcastle University.
Volunteers are vital for red squirrel conservation and we have used workshops, focus groups and interviews to elicit more than 50 volunteers’ experiences. Our report details volunteer motivations and outlines the challenges and barriers volunteers face. We are also exploring how the actions of conservation organisations, such as the Red Squirrels United partners, can improve volunteers’ experiences and increase volunteer numbers. Having observed volunteers’ difficulties in engaging landowners and gaining access for grey-squirrel control, we have also interviewed over 30 land managers/landowners to explore levels of support and engagement in squirrel management. These findings (due later in 2019) will be of relevance to other conservation and wildlife-management efforts.
In 2019, we will be overseeing a survey of communities in the Red Squirrel United delivery areas to assess the programme’s impact on knowledge and attitudes towards squirrels and their management and whether there has been an increase in volunteer activity. Responses will be compared to those from our 2015 nationwide public survey, and community surveys undertaken throughout the project. Earlier findings demonstrated limited knowledge of the impact grey squirrels have on red squirrels but an acceptance that humane controls could be justified where negative impacts were observed.