Abstract
Impacts of human activity on forest ecosystems are most pronounced in the temperate region. Simplification of stand structure has resulted in diminished ecosystem function and biodiversity decline, raising much debate over future management policies. Ecosystem functions and biodiversity may be enhanced by managing forests for increased structural complexity. However, processes that determine relationships among structural complexity, ecosystem functions, and biodiversity of forest ecosystems remain unclear. In this review, we present examples of studies conducted at two canopy research facilities located in different types of temperate forest to illustrate that structural complexity of forest canopies enhances stand productivity and biodiversity: (1) development of structurally complex canopies comprising various tree species enhances stand productivity by promoting complementary resource utilization among species through spatial, physiological, and temporal differentiation; and (2) development of complex canopy structure enhances biodiversity of canopy-dwelling organisms by creating a resource-rich habitat. These ecological observations stress the importance of including three-dimensional structural attributes of forest canopies in management plans and silvicultural prescriptions that aim to maintain ecosystem functions and biodiversity. FOR. SCI. 50(3):342–355.