High Quality Content by WIKIPEDIA articles Mixed forests are a temperate and humid biome. The typical structure of these forests includes four layers. The uppermost layer is the canopy composed of tall mature trees ranging from 33 to 66 m (100 to 200 feet) high. Below the canopy is the three-layered, shade-tolerant understory that is roughly 9 to 15 m (30 to 50 feet) shorter than the canopy. The top layer of the understory is the sub-canopy which...