Ring barking or girdling can kill a tree. It happens when the tree’s bark is removed right the way round its trunk. Accidental girdling may be the result of a carelessly used strimmer, or over-tight wires and ties; it might be mammals gnawing on the bark or, in the case of deer, rubbing their antlers against it.
Trees have two kinds of transport cells. There is xylem which takes water and minerals from the roots to the leaves at the top of the tree, and there is phloem which brings the sugars that the leaves make back down to feed the roots, trunk and branches. Xylem is the sapwood, the heartwood is old inactive xylem darkened with stored sugars, and phloem is the inner part of the bark.
Ring barking strips away the phloem and the tree begins to starve because the sugars that are made in the leaves are no longer being delivered to the roots. The xylem remains and keeps delivering water to the leaves but unless the tree can sprout new growth below the girdle, it will slowly die.
Foresters sometimes use ring-barking purposefully, to manage their trees: to make space and resource for a rare species, to bring light to the forest floor to encourage germination. A ring barked tree will die but stay upright in woodland, increasing, as it decays, the range of habitat for birds, insects and fungi.
For example, stag beetles, our largest beetle, lay their eggs in the soil near to rotting wood. When they hatch, the larvae make their way into the wood and live there for several years before they pupate.
And then, of course, there is vandalism; FoSCP have not yet decided what will happen to the trees that have been ring barked by vandals in the park. They may be left, upright or felled, to provide habitat for species that live on or in rotting wood or they may be removed when the copse is thinned.
Header image by DKG; others by Google Images
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