Abstract
Seven stands of Chamaecyparis obtusa plantations with different ages, ranging from 20240 years, were investigated to understand their development patterns in relation to the forest practices. Roughly 200-year-old plantations of Chamaecyparis obtusa not only showed larger stem size and stand volume, but also had different species composition and stand structure from plantations less than 100 years old. The old-aged stands developed a multiple layered structure composed of planted trees at the upper layer and broad-leaved trees at the lower layers. These differences in stand structure among old-aged coniferous plantations may be associated with canopy openings caused by logging in the past, as well as the occurrence of standing dead.Therefore, old-aged coniferous plantations need continuous tree density control, even after 100 years, to maintain their vitality as forest ecosystems.
