My head is still full of new ideas, information and insights from our conference on Thursday 27th June on “Chalara, Other Threats and Resilient Woodland Landscapes”. The Woodland Trust set the event up, working with Defra, to bring together a truly multidisciplinary group of 40 experts – scientists, researchers, forest pathologists, woodland managers, professional bodies, government agencies involved in woodland and plant health, and wildlife and conservation bodies too. With participants from some of our top academic institutions, and participants from England, Scotland, Wales and Denmark, there were excellent opportunities to share experience and learning as well as identify the key gaps in knowledge and practice that we need to address.
Professor Ian Boyd, Defra Chief Scientist, presented his thoughts on the government response to his Taskforce Report, set up to address the pressing problems of tree disease. Prof Boyd made it clear that Defra and the government cannot tackle these problems alone and will play their part through regulations, statutory controls and helping to co-ordinate activity. But getting to grips with what happens in our woods and forests, how to engage the wider public, and what practical action to take to make our woods more resilient will rely on bodies like the Woodland Trust, and others, to be part of a wider and ongoing response to these challenges.
There was much agreement on the scale of the task we face and the very real and pressing threats to our valuable trees, woods and forests – not least the risks to wildlife, environmental quality, and the beauty and cultural significance of the landscapes that we all cherish.
There was clear support on the need to tighten ‘biosecurity’ through better control of plant imports – and the need to involve everyone who plays a part in this from plant importers, to nurseries, retailers and right through to the customers. Although, this was tempered by a recognition that import controls and regulations will help, but with massive volumes of global trade and personal travel this cannot guarantee to keep everything out. In addition, we must not fall into the trap of thinking we can always conquer nature – there will still be pests and diseases that get here under their own steam, by various natural means. After all, there is strong evidence that chalara ash disease arrived here as windblown spores, infecting established trees in the south and east of England, as well as being ‘assisted’ in to the country on infected ash saplings imported for planting.
By far the most interesting part of the discussion, and perhaps the more optimistic, was identifying how we might rise to the challenge of making our precious trees and woods more resilient in the face of these on going and inevitable threats. With the input of renowned woodland ecologist, Keith Kirby from University of Oxford, the group considered how the natural and cultural history of our woods has shaped them – and what we can do to give nature a helping hand.
This cannot be a ‘one size fits all’ approach and there is no simple template that all woodland owners and managers should follow – in fact the tendency to try and manage all of our woods in the same way in the past or previous suddenly shifts in management resulting from pursuit of narrow theories has probably made them more vulnerable today. A vulnerability compounded by the continuing gradual loss of woodland and the fragmentation of woods and other habitats, leaving them disconnected and isolated.
But some key principles are emerging. Our woods will be more resilient if they contain a wider range of native species, and have a more diverse structure too – so that we have a good mix of types of trees and a range of young, established and older trees. This means they are less likely to all be seriously affected at the same time by a sudden pest, disease, or climatic ‘event’ – different species and ages of trees will respond in different ways. Resilience will also grow with an increase in the genetic range of our native trees – this means thinking carefully about how we might use the planting of new trees alongside processes of natural regeneration and expansion of our most precious woods. Of key importance is the nature of any new trees that we plant – we want to maintain our focus on native species but must look carefully at where the seed for those trees has been collected and how they have been raised.
It’s the challenge of addressing some of these landscape scale issues that is perhaps the most exciting, and this is where the need to protect, restore and expand our woods comes together in a more integrated way. Continuing to gradually expand our native woodland cover by planting new woods that buffer, link and extend our surviving ancient woods is crucial in building resilience. New native woods will also deliver these benefits as part of much wider habitat networks – reinforcing river side habitats with trees, strengthening hedgerows, protecting our ancient and veteran trees – shelterbelts and buffer strips of trees and woods integrated into farming that deliver benefits for the farmer in the form of shade, shelter, better managed runoff, improved water quality.
This better connected landscape, with more trees and woods, with more variety and diversity, will look more attractive, and will be much better for wildlife and people. It won’t stop tree pests and diseases, but it will mean our natural environment is much more capable of bouncing back and recovering from these inevitable impacts. The Trust’s site at Pound farm in Suffolk is a delightful native wood of mixed species. Sadly, ash disease is already killing many of the young ash trees there. But the natural regeneration of oak, field maple and hawthorn is in there too – this means the diversity of the woodland will guarantee its survival as a native wood.
Sharing his experience of research and tree breeding for disease resistant ash in Denmark, Prof Erik Kjaer from the University of Copenhagen, confirmed that a small proportion (around 2%) of ash may be naturally resistant or tolerant to chalara. There are also good signs that this characteristic can be passed on to progeny of those surviving trees. The Forestry Commission led planting trials of ash here in the UK, and genetic mapping of ash being done by Prof Allan Downie of the John Innes Centre, can build on this Danish knowledge and holds out some hope of finding resistant ash here in the UK. This, of course, will all take some time. Meanwhile, there is little that can be done to stop the spread of chalara, but so much more to do to make our woods more resilient and think about preparing for the inevitable impact on our hedgerows and wider landscape.