This is Populus tremula, the Aspen Tree. Quite a common tree across the UK, the Aspen’s leaves are much smaller and rounder than the Black Poplar, and in particular its leaf stalk, or petiole, is flattened. This creates an interesting and unmissable effect when there is a breeze blowing, as the leaves will shake and tremble. Also, this tree is one of the main staple trees for the match making industry.