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Suffolk Natural History, Vol. 35
ANCIENT H O R N B E A M TREES IN BURGATE WOOD, SUFFOLK J. WHITE AND N. SIBBETT Burgatc Wood is an ancient coppice woodland south-west of Diss (TM075757) covering 30-5 ha. It has much hazel coppice and areas of hornbeam coppice, with a light Cover of oak Standards mostly under 70 years old. Ancient coppice stools, particularly of ash, are abundant. The south-east quarter of Burgate Wood contains historic earthworks, including a moat which has recently become a scheduled ancient monument. Amongst these earthworks are fourteen ancient, mostly pollarded, hornbeam trees. Burgate Wood is on thc western edge of a native hornbeam stronghold within East Anglia (Perring & Walters, 1990). The trees in the wood are likely to be descendants from the original native stock, although it is not possiblc to teil if they have grown naturally or were planted. It is unlikely that, in a hornbeam area, hornbeam would have been brought in from elsewhere because it was an unpopulär species; its wood is hard to work and its use is limited compared with ash, oak and hazel. English Nature commissioned John White, a Consultant dendrologist, to study the trees to aid management decisions. Ash coppice stools in Burgate Wood were measured, the largest being 232 cm in diameter. This is 79 cm greater than the largest stool in Hayley Wood, Cambridgeshire, which may be 400 years old (Rackham, 1986). At Silk Wood, Gloucestershire, large ash stools investigated by Rackham were found to be growing at the rate of 1 cm diameter every 7-5 years. At this rate, the Burgatc Wood ash stool could have 300 years more growth than the Hayley Wood ash, making it 700 years old. Hazel and maple stools have also been measured in Burgate Wood and are of comparable age. The ancient hornbeam trees are believed to be contemporaneous with the ash, although hornbeam is not well researched (White, 1998). Each of the fourteen ancient hornbeam trees has been tagged with a numbered aluminium label on the north side between 2 and 2-5 m above ground. The stem diameter has been measured, and the basal area of the stem has been calculated from this. The basal area is of great help in determining the age of trees. In thc first decades of a tree's life, growth is fast and the rings wide. After "maturity", trees tend to increase their basal area by the same amount each year. As the diameter gets bigger, each annual ring is slightly narrower than the previous one but has the same cross-sectional area. The age of a tree can be detcrmined from its diameter basal area, the width of thc recent annual rings, and measurements or estimates of its initial fast growth. Ring growth on branches can be used to estimate early tree growth, and two broken branches were found to be 68 years old with 2-5 mm average ring width. The structure and height of each tree was also measured. The objective for these old trees is to maintain them for as long as possible, hopefully for many more centuries. The key factor is maintaining the life of the "bolling" or trunk. To do this, the branches must be kept free from competition from adjacent trees. If the branches grow too heavy for the bolling, they may collapse and split the bolling into pieces. Specific management äctions are planned for each tree, which includes reduction of surrounding Vegetation,
Trans. Suffolk Nat. Soc. 35 (1999)