Sycamore is commonly found growing in disused quarries and can even be found in cracks on rock faces. Out of 48 surveyed chalk and limestone quarries in England 22 contained sycamore but only seven were found to have individuals in the youngest age classes. However, it only becomes established if seeds are readily available. In all instances sycamore is present but the timing of its establishment varies with the site. At a Bristol site undeveloped for 40 years buddleia dominated but was starting to be overtopped by sycamore which Gilbert describes as being probably its natural successor in towns.
Succession includes stages dominated by grasses, bramble and trees.
Woody plants become established throughout the first two stages for about 10 years. Also he notes that although a very large number of seedlings and saplings are produced in urban areas few turn into mature trees. The following year he found that many sycamore seedlings became established. The reverse was true for Quercus robur . It is clear that both disturbance and lack of plant competition favour the establishment of sycamore in all these man-made habitats, and Crawley's work indicates that a certain degree of grazing limits grass competition.