Growth and development of loblolly pine in a spacing trial planted in Hawaii.

摘要

Loblolly pine (Pinus taeda) was planted at 4 square spacings (1.8, 2.4, 3.0, and 3.7 m) on the Island of Maui, Hawaii (USA) in 1961, and measured periodically for 34 yr. Patterns of stand growth and development were examined and compared with yieldmodel estimates of stand characteristics of plantations of the same initial spacings, ages, and site index in the SE USA. The Hawaiian plantings had much higher survival at all spacings and sustained high diameter growth in the face of intense competition. At 34 yr old, the 1.8 m spacing had 1585 stems/ha averaging 24.1 m tall and with DBH (diameter at breast height) 28.8 cm; the widest spacing (3.7 m) had 725 stems/ha, and was 26.1 m tall with DBH 38.2 cm. The highest basal areas (～100 m2/ha) were double the maximum values attained in the SE USA and were reflected in similar differences in volume yields. The Hawaiian plantings demonstrate that growth potential of loblolly pine is far greater than is apparent from observations on plantations in its native habitat. To capture this potential in other situations, research must identify the tree, stand, and environmental characteristics associated with low mortality rates and high diameter growth in Hawaii, and, conversely, the factors that limit loblolly's potential in the SE USA.