The sycamore flowers in April, shortly after the leaves appear. The seeds ripen in autumn; their spiralling descent increases the time it takes for them to fall to the ground, and so maximises the chance that they will be dispersed further away from the parent tree in the wind (4). The maximum age of a sycamore is thought to be around 500 years (4). This species spreads very rapidly, quickly colonising new areas; it is removed from sensitive habitats by conservationists as it shades out native species. The tree is also notorious for producing a mucus-like slime as the leaves decompose, creating menacing conditions on footpaths, and bringing trains to a standstill. However, the leaves decompose rapidly and are now known to give a 'boost' to earthworm numbers. Furthermore, in urban areas, sycamores are often the only source of insect food (chiefly aphids) for birds such as house martens (Delichon urbica) (3).
Although it is not a native species, the sycamore has become a firmly established feature of many local cultures, as well as emblems of certain places. In Wales, clogs and love-spoons are fashioned from sycamore wood, harvest cakes were baked upon sycamore leaves in the West-country, and sycamores are often one of the first trees a child learns to recognise, by virtue of the 'helicopter' seeds. There are also many 'landmark' sycamores around the country, the most famous of which is the Martyrs' Tree on Tolpuddle Green in Dorset. In the 1830s, the Tolpuddle Martyrs formed the first agricultural trade union at meetings held beneath this famous tree; they were deported to Australia, as meetings of this kind were illegal at that time. The tree still survives, and is currently cared for by the Trades Union Congress (3).