C O N T E X T 1 1 2 : N O V E M B E R 2 0 0 9 35 exhibit characteristic ‘knuckles’, hinting at a history of pollarding at some time in the past. Glasgow City Council’s current policy, supported by Jamieson and others, is no longer to lop, top or pollard trees. This is on the grounds that these are disfiguring practices which damage a tree’s health and shorten its lifespan. Instead, the council offers advice on tree pruning, crown thinning and crown lifting, a policy endorsed by the Royal Horticultural Society where regular pollarding has lapsed. Yet there are those who would contend that pollarding can prolong rather than shorten the life of a tree, provided that it does not expose old wood to rot, and that well done it can make a positive contribution to the townscape. The Glasgow case raises a number of questions.Was it always the intention to fell and replant the trees once they reached a certain size? Or was the choice of lime made precisely because it was intended to pollard trees in roadside strips and smaller gardens, so as to keep them in proportion with the surrounding architecture? What is certain is that, left unmanaged, mature lime trees can reach a height of around 30 metres (100 feet), with a canopy width of around 20 metres (65 feet). In a number of Scotland’s towns and cities where pollarding is, or has been, practised, garden trees have commonly been restricted to approximately five metres (16 feet) in height. Terrace-front trees have been maintained at around 10 metres (30–35 feet). Trees in squares and along main routes, further from buildings, have been allowed to reach something close to their natural form and height at around 20 metres (65–70 feet). Is this a pattern which can be observed elsewhere in Britain? Properly done, pollarding can take a number of forms. The most extreme of these involves cutting back new growth to a single main stem, resulting in a single bushy regrowth in the shape of a lollipop or bottle-brush. Less extreme is the branching or multistemmed pollard, where selected branches are allowed to develop before pollarding. This results in trees with an interesting, almost architectural character. Variations on this are pleaching and plashing, where the branches of adjacent trees are closely interwoven to form a continuous green wall or hedge.To be effective, intensive pollarding must be repeated every two to five years. Where regular pollarding ceases and large branches are allowed to develop, the ‘knuckles’ remain as weak points in the tree’s structure, liable to break when put under stress. Many local authorities who choose to maintain their street trees with a programme of regular pollarding do so against considerable opposition from wellintentioned individuals or groups who would prefer the trees to be allowed to take on a more natural form. Given the need to pollard trees on a regular basis, there are obvious short-term financial benefits to come from a reduction or cessation of the practice.Yet local authorities need to be mindful of the likely longer-term and adverse consequences of such a move. When forest trees such as lime are planted in streets or small gardens, they need to be properly managed. Otherwise they will eventually become large and over mature, and could damage neighbouring properties and people. Wholesale felling may become the only solution. Unless followed immediately by replanting, surrounding properties are robbed of their green setting and prospect. The question also arises as to whether replacement planting should be done using the same trees, or with species of smaller stature. These would not require such regular pruning, but are likely to have a shorter life-span than the original trees. Clearly, adopting the latter approach would result in a significant change in historic landscape and townscape character. If pollarding is favoured, how easy is it to find arborists with the necessary knowledge and skills? Indeed, how skilled do the practitioners have to be, if adequately trained and supervised? The author’s observations, together with Jamieson’s study, point to the need for further research if we are to achieve a better understanding of the design intentions of those who planned and planted our towns and cities. It would be interesting to hear from those in local authorities who have been responsible for the formulation of policies to manage or replace street trees in towns, or who have had the job of negotiating with property owners over the treatment of their trees. Christopher Dingwall, a freelance landscape historian with a special interest in gardens and designed landscapes, is a former conservation officer for the Garden History Society in Scotland. He lectures in Dundee and is a voluntary tree warden with Perth and Kinross Council. Pollarded limes at Newtyle, Perthshire Branching pollards in Perth
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