Thursday, 15 October 2009

Don't dismiss sycamore out of hand

First introduced to Britain during the 16th Century, the Sycamore is a tree that is often dismissed as being of little value to wildlife. Many of those involved in nature conservation refer to it as a ‘weed’, spending hours pulling Sycamore seedlings that have established themselves in some piece of ‘natural’ woodland. Gardeners are also deterred by the huge numbers of seeds that are produced, each one a miniature marvel of aerodynamic efficiency, not to mention the leaves which attract large numbers of aphids and their sticky residue.

It is the production of so many seeds, together with their efficient dispersal mechanism, that has made the Sycamore such an effective colonist. Tolerant of salt spray, the Sycamore has even become established on dune systems around parts of our coastline. Its tolerance of pollutants has also enabled the Sycamore to establish itself within larger urban centres, where it can be found lining railway embankments, depositing ‘the wrong sort of leaves’ onto the nation’s railway tracks.

The Sycamore is capable of rapid growth, which is one of the reasons why it was so favoured for introduction to the great landscaped parks that were a feature of the 18th and early 19th centuries. This growth, coupled with the dense shade cast from the canopy, supports the perception that the Sycamore is an invasive species capable of shading out native trees within broad-leaved woodland. Conservationists feared that their native woodlands would be replaced by monocultures of Sycamore, impacting upon wider biodiversity because the tree supports only a small number of plant-feeding invertebrate species. Interestingly, however, the Sycamore actually delivers the greatest insect productivity, in terms of weight, of any widespread tree, even beating the mighty oak. Admittedly, most of the biomass is made up of aphids, but these are likely to be an important food source for birds and other creatures, particularly in urban areas and at certain times of the year.

Sycamore also has an economic and cultural significance. Not only is it fast growing but the wood it produces is clean, pale, with a fine grain and no real odour. This makes it an ideal wood for woodturners and for the production of wooden products for the kitchen (such as bread boards and rolling pins). There are a number of mature Sycamores of cultural importance, perhaps the most famous of which sits on the green in the village of Tolpuddle. It was under this Sycamore that the Tolpuddle martyrs held their union meetings during the 1830s.

Like many others, I remain in two minds about the Sycamore. It is an introduced species and one of the ’big seven’ invasive plants but it does deliver some benefits that may not be obvious from a cursory glance.

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