Influence of vital growth space on height and diameter of Pinus taeda L.

The present study evaluated the performance of Pinus taeda L. in the region of lrati, Southern Brazil, growing at different vital spaces (ranging from 1 m(2) and 16 m(2) per tree), provided by nine different areas given to trees in a field trial installed as a randomized block design with five replications, using seedlings from a clonal seed orchard. Data were collected when trees were seven years old after planting; with height and circumference measured 1.3 m above ground in the 25 internal trees in each plot. Data obtained yielded dendrometric variables such as height, diameter at breast height (dbh) and basal area, as well as mean annual increments (MAI). Tree heights varied from 8.51 m to 10.3 m and were higher in smaller areas. In large areas the trees reached greater dbh values: from 7.95 cm to 18.78 cm. The estimated basal area was inversely proportional to the increase in vital space area, ranging from 56.11 m(2).ha(-1) to 17.17 m(2).ha(-1). Mean MAI ranged from 1.21 m.year(-1) to 1.44 m.year(-1) for height; 1.13 cm.year(-1) to 2.68 cm.year(-1) for dbh; and 2.45 m(2).ha(-1).year(-1) to 8.01 m(2).ha(-1).year(-1) for basal area. This is a good performance of Pinus taeda in the central-southern region of Parana State. For a better occupation of space and consequent higher stem biomass production (represented by basal area), independent of tree diameter; a smaller vital space like 1 m(2) can be chosen. If trees with greater diameter are desired, a larger vital space area of up to 12 m(2) is recommended. The best yields resulting in great basal area and large diameter can be found at vital spaces between 4 m(2) and 6 m(2) per tree.