News and blog Friday's Farming Thoughts Entry #10 - Charlotte Marshall: Wonderings and Wanderings About Wood Pasture Wood pasture is something that is quite new to me. I had heard of the term before, but the image that it conjures up is usually the grounds of stately homes that I have walked through on days out, not an environment that I come across on farms. Since coming to work at FWAG I have been assisting Joanne Leigh on various projects linked to the facilitation fund farmer group that she manages – the Carrant Catchment Area Restoration Project. The farms are mostly on the Gloucestershire/Worcestershire border surrounding the Bredon Hill SAC and SSSIs, designated for their species rich meadows and abundance of saproxylic insects (insects that rely on decaying wood for part of their life cycle). The collection of invertebrates found at Bredon Hill is one of the most abundant in the UK and is specifically linked to the wood pasture habitats on the hill. Managing these wood pasture habitats is a key goal of the facilitation fund group. To do this, we have worked with the Ancients of the Future Project, part of Back from the Brink, bringing us into contact with an incredible group of experts who have helped us to understand and unpick the best way to manage these habitats. The food chain that underpins wood pasture is fascinating and rather convoluted. Ancient and veteran trees are a good place to start, with their hollowed trunks, standing and fallen deadwood and partial decay. Veteran and ancient trees in turn provide habitat for many fungi, lichen and insect species that can survive nowhere else. In fact, 6% of British inverts rely on deadwood that is present in habitats like wood pasture. Fungi fulfil the role of detritivore, removing dead material from trees and the soil and turning it into new soil to provide a nutrient source for plants and trees. In the ground, mycorrhizal fungi associate with roots in the soil, facilitating water and nutrient exchange. Other fungi produce the glomalin that sticks soil together into aggregates. On trees, fungi enter through a wound and create a cavity. Far from being a problem, the fungi, usually species of red rot fungi, digest the cellulose, hemicellulose and lignin that makes up the wood and bark of the tree, producing the red/brown powder-like material the we often see around tree trunks and that eventually returns to the soil. This is part of the tree cycle, and the tree will persist for many years without being affected. Not all fungi are beneficial; white rot fungi attack roots, producing a spongy material that will eventually cause tree collapse. As well as fungi, many lichen species only exist in wood pasture habitats. Lichens are part fungi and part algae and are often seen encrusting veteran tree bark or forming crests on branches. Lichen are very susceptible to changes in air quality, climate, bark chemistry etc and so are often specifically adapted to certain tree species. There are some species of lichen, such as the pinhead lichen, that were elm specialists and have now been lost, and others are threatened by ash dieback. Saproxylic insects are the next part of the chain. The larvae of many species, such as stag beetles, feed on decaying wood of veteran and ancient trees being processed by fungi, so wood pasture is an essential habitat for them in the UK. The Violet click beetle feeds directly on wood mould and is only found at Bredon Hill and one other site, Moccas Park, in the UK. The final part of the chain is bats. Wood pasture at Bredon Hill provides a key habitat for rare bat species such as Barbastelle and Bechstein’s bats. Ancient trees often make excellent roosting places, and saproxylic insects, among many other insect species, are a good food source. In addition, the trees provide connectivity between food sources and roosting sites, reducing the bats need to spend energy flying across open spaces in search of food. How can we manage and maintain these wonderful habitats for such a range of species? The main thing is to ensure a “continuity of conditions” i.e a good mix of tree ages and stages of veteranisation. To do this, dead and decaying wood should be left, along with standing and fallen deadwood. Deadwood is often piled up under trees, and this creates brilliant habitat for many species, however the act of creating a pile can be disruptive to lichen in particular, so where practical it is best to leave it where it lands. Planting new trees is also a key part of maintaining the continuity of conditions needed. This can take the form of trees in fields or new trees in hedgerows. Hedgerows managed correctly are hugely important corridors for wildlife of all shapes and sizes, and have a huge value in connecting habitats such as wood pasture. Permanent pasture around the trees, managed by sympathetic grazing with livestock preserves the tree root system and provides stability for the tree. The role of trees as shelter and a source of alternative browsing for livestock is extremely important. Ivy control is important for lichens, but it’s also important not to totally remove all ivy stems once cut as occasionally they provide roosting habitat for bats. A good supply of nectar plants nearby is also essential to encourage pollinators, along with minimal use of herbicides and pesticides. Hawthorn and blackthorn are good examples of nectar sources that often occur in wood pasture habitats and in hedgerows, but umbellifers and other verge-side or arable margin species are also incredibly valuable. At Bredon Hill, a recent coordinated effort between landowners, Natural England and ourselves at FWAG has produced a plan for two Higher Tier countryside stewardship schemes that will hopefully come into effect next year. Both include options for both restoration and creation of wood pasture to help to conserve this wonderful species assemblage and habitat type. There is lots to do and lots to learn, and I look forward to wondering through much more wood pasture in the future.