34 C O N T E X T 1 1 2 : N O V E M B E R 2 0 0 9 Christopher Dingwall Pollarding trees in towns While trees can make a positive contribution to urban landscapes, their management arouses strong feelings among property owners and local authorities. Next to the scourge of the Leyland cypress (Cupressocyparis x leylandii) there can be few subjects which excite more controversy in the arboreal world than the pruning or pollarding of street trees in towns. A quick search on the internet will yield numerous instances across the length and breadth of Britain. These involve disputes over tree preservation orders and the management of trees in conservation areas. While some local authorities are endeavouring to justify their policy of pollarding street trees, others are seeking to explain why they have chosen to ban this form of management. Traditional pollarding – the regular cutting-back of the crown of a tree to promote new growth – has been practised for centuries, especially in rural areas. It is used to create fresh foliage for animal fodder, to provide rods for basket weaving, or to generate firewood. In coppicing, trees are reduced to a ‘stool’ at or near ground level. Pollarding involves cutting-back a tree to a point some distance above the ground. This was originally intended to keep new growth beyond the reach of browsing livestock. In most trees, repeated pollarding leads to the formation of a pollard head or ‘knuckle’, from which the new growth springs after each cutting. A single episode of pollarding can be used to encourage multiple branches to break from a single point on the stem, resulting in the shapely crown seen in many parkland trees. Most fashionable in the formal gardens of the 17th and 18th centuries, pollarding remained popular in European gardening and arboriculture during the 19th and 20th centuries. It was used as a means of controlling street trees in towns and cities, to prevent overshadowing of gardens, and to maintain outward views from buildings. Some tree species such as lime (Tilia x europea), London plane (Platanus x acerifolia) and sycamore (Acer pseudoplatanus) respond well to this kind of treatment. Others such as beech (Fagus sylvatica), birch (Betula spp.) and most conifers do not. This characteristic, combined with a tolerance of smoke pollution, meant that the most resilient trees such as lime, elm and plane, which combined this characteristic with a tolerance of smoke pollution, were favoured for the planting of urban streets and squares. As Charles McIntosh observed in The Book of the Garden (1853), ‘the Lime has been a popular city tree for ages; it bears cutting and training, so as to form a verdant wall, and for this purpose is much used’. John Claudius Loudon noted of lime in his Arboretum et Fruticetum Britannicum (1854) that ‘for architectural gardening it is well adapted, from the patience with which it bears the knife or the shears’. Lime is also notable for the intoxicating fragrance of its flowers.Yet its widespread use in urban planting was criticised by others, such as nature-lovingWilliam Robinson. In his account of The Parks, Gardens and Promenades of Paris (1869), Robinson deplored the lime as ‘the worst of all trees for cities… and the extensive use of it in our streets the most blameworthy of bad practices in either town or country planting… [through its] periodical mutilation.’ Add to this the fact that aphids feeding on the trees secrete a sticky substance known as honeydew, which can coat cars, pavements and other property, and one can see why it does not always find favour with today’s town dwellers. A study being carried out by Fiona Jamieson in GlasgowWest conservation area has served to highlight a number of issues. The rapid expansion of Glasgow in the mid-19th century included the development of areas such as Hillhead, Dowanhill and Kelvinside as high-class suburbs to the west of the city centre.These areas were characterised by fine villas and elegant terraces. The planting of lime with an understorey of evergreen shrubs in communal gardens and roadside strips was a major element. Lime was the favoured species, being wind-firm and tolerant of atmospheric pollution. It made up around 70 per cent of the trees in the West End. Used in both street planting and private gardens, it has become a distinctive feature of the townscape. It is noteworthy that a majority of the trees in the conservation area Trees in Glasgow’sWest End
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