This results in large areas covered by a single clone that may be more than a thousand years old. Old clones have old-age problems, and the size of the clonal patches reduces cross pollination, further reducing biodiversity. The young branchlets are reddish-brown and shiny but turn gray and become roughened after the first year. Buds have a brown, varnished appearance and are often curved toward the twig. The leaves alternate along the stem and are broadly oval in shape.
Foliage is green and shiny above and dull green below.
Unlike the cottonwood, the leaves do not have translucent borders. The flattened petiole results in the fluttering of the leaves and the name, quaking aspen. The flowers, like those of all the poplar family, are of two kinds born on separate trees. The fruit ripens in late spring or early summer, before the full expansion of the leaves, and contains tiny, rounded seeds. The wood is light brown, surrounded with nearly white sapwood.