Birch is a thin-leaved deciduous hardwood tree and is unfazed by heat and humidity. Particularly attractive in the winter months, it has exfoliating bark in shades ranging from light taupe to cinnamon brown, with some cultivars displaying multiple layers of color. The small, triangular double-toothed leaves turn a buttery yellow in autumn. Tolerant of wet soil, river birch is a useful tree for rain gardens, low areas, and the banks of rivers and streams.