| Cumloden oak - a verern multistem oak in a historic wood pasture setting at Cumloden estate near Newton Stewart. This oak seems to be growing on an ancient field clearance cairn.
Photo: © Peter Quelch |
Ancient wood pasture consists of scattered trees in a grassland or heathland setting. It is a habitat fashioned by generations of rural people grazing livestock and maintaining trees on the same site. The grazing needed to be just right; light enough to allow trees to grow (and occasionally to regenerate), but sufficient to prevent a woodland forming and shading out the pasture. Where this was achieved over a long period of time, a unique habitat has developed which today harbours many rare and important species. The term 'ancient wood pasture' includes the parklands and designed landscapes of some big estates, the vestiges of royal and noble hunting forests and a range of smaller sites which perhaps survived through the vagaries of chance and circumstance. The latter are perhaps some of the most 'natural' areas of landscape left, a direct progression from the post-glacial 'wildwood' . and why is it important? The trees are a key feature. They are often very old, sometimes very big and may have been cut back (pollarded) in the past. These veteran trees can be centuries old and host long-established communities of fungi, lichens and specialist insects. They are also home to birds, bats and other wildlife. Having trees like this, surrounded by nectar-filled wild flowers and open semi-natural grassland creates a special wildlife habitat and a classic landscape. Remnants of this landscape have survived throughout Scotland although the extensive rural practices which created and maintained it have died out. The wood pasture that remains provides evidence from the centuries past of the traditional stewardship and careful husbandry that formed this great Scottish landscape. The simplest identifying feature of wood pasture is the presence of veteran trees. What is a veteran tree? When you begin to look, you can find veteran trees throughout Scotland; in churchyards, gardens, ancient woodlands, field boundaries and in the remaining areas of parkland and wood-pasture. It is difficult to define precisely what constitutes a veteran tree, but the general characteristics are easily appreciated. There are many older veteran trees around that have been standing for hundreds of years, a few that can mark a millennium and the odd example such as the Fortingall yew which easily predates Christianity. Old, however, can be a relative term. Willows or birches start getting old when they are sixty or seventy; a 200-year-old oak will be only reaching its prime. Technically, a tree becomes 'veteran' when the actual volume of new wood created each year starts to decrease. This is associated with a reduction of the canopy, the death and loss of branches and the advance of decay fungi which hollow out the heartwood and the broken stumps of branches. This period of 'retrenchment' may last for decades or even centuries while the tree decays and maintains a sparse living crown. Trees such as these characteristically feature the "deadwood" habitats that are so important for the range of epiphytic and saproxylic plants, invertebrates and mammals associated with big old trees. |