Wood Growth Determined from Growth Ring Analysis in Red Pine (Pinus Resinosa) Trees Forced to Lean by a Hurricane

Abstract

Leaning red pine (Pinus resinosa) trees at Harvard Forest in Petersham, Massachusetts, U.S.A., were sampled for wood growth studies 50 years after they were displaced by a hurricane. Before the hurricane incursion, ring width varied among trees and from year to year but not among radiL After the hurricane, between-tree variation in ring width was again significant but it was not appreciably due to angle of displacement (AOD) of the bole. Wood growth distribution along the bole in the leaning trees was complex. Between- radius variation in ring width was significant in the leaning boles; ring width was largest on the lower side. On the average ring width decreased as tree age increased but the variation was much less on the upper than on the lower side. Ring area tended to decrease with increase in age but the relationship was strongest in the least displaced bole and vice versa. Asymmetrie growth ratio increased with AOD of a bole and varied with year of wood formation but was not related to cambium age. Graphs of height above the ground on percentage pith eccentricity exhibited a sinuous shape like that of the trees. Cumulative growth and mean annual increment of height and volume increased with tree age. Current annual increment of height and volurne decreased for 9 and 5 years after the hurricane and after the 64th and 69th year of the tree, respectively. Form factor increased after pruning but decreased later with age. Precipitation was not closely related to ring width in the leaning boles.