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

Loblolly pine taeda L) was planted at four square spacings (1.8, 2.4, 3.0, and 3.7 m) on the Island of Maui in 1961, and measured periodically for 34 years. Patterns of stand growth and development were examined and compared with yield model estimates of stand characteristics of plantations of the same initial spacings, ages, and site index in the southeastern United States. The Hawaiian plantings had much higher survival at all spacings and sustained high diameter growth in the face of intense competition. At Age 34, the 1.8 m spacing had 1585 stern&a averaging 24.1 m tall and 28.8 cm DBH; the widest spacing (3.7 m) had 725 stems/ha, 26.1 m tall and 38.2 cm DBH. The highest basal areas (-100 m’/ha) were double maxima attained in the southeastern United States 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 southeastern United States.