Stemwood Production Patterns in Ponderosa Pine: Effects of Stand Dynamics and Other Factors

Growth patterns of vertical stems in nine ponderosa pines from a stand in the southern Sierra Nevada were analyzed for recent changes due to stand dominance position, age, climate, and ozone exposure. Large positive correlations were found between increments in volume growth and basal area at d.b.h. The results indicated that patterns of wood distribution along the bole were associated with age, competitive position, and release from competition. A multiple regression model using winter and spring precipitation adequately explained short-term growth fluctuations during 1920-1955 and predicted growth during 1956-1985 for the trees as a group. A prominent feature of all volume, basal area, and ring width series was a growth response to a selective harvest in 1965. Increments in gross volume increased throughout the bole of all trees after thinning. This increasing trend continued for young and dominant trees but declined for older nondominant trees. It was difficult to determine whether ozone has contributed to these growth declines because the decline pattern was also consistent with competitive suppression. There is no conclusive evidence that growth changes vertically along the bole or through time are due to ozone exposure. Acknowledgments: We thank Jennifer Towne and Kenneth Stolte for their assistance with field work, and George H. Pollock and Lindsay J. Robinson for measuring samples in the laboratory. We thank David LeBlanc for his comments on an earlier version of this paper; and Fredrick Smith, Robert Musselman, and Merrill Kaufman for their review comments. We also thank the timber management staff of the Sequoia National Forest for their cooperation. Stemwood production patterns in ponderosa pine: effects of stand dynamics and other factors. Growth patterns of vertical stems in nine ponderosa pines from a stand in the southern Sierra Nevada were analyzed for recent changes due to stand dominance position, age, climate, and ozone exposure. Increments in gross bole volume and changes in growth rate were calculated for each tree. Large positive correlations were found between increments in volume growth and basal area at d.b.h. Increments in gross bole volume indicated that some trees declined in growth despite a large release of growth in 1965. Patterns of stemwood distribution along the bole were analyzed by comparing Growth Layer Profiles (GLP's) of ring width and basal area increment series. Spearman correlations were calculated between basal area increments along the bole and normalized bole volume increments. The results indicated that patterns of wood distribution along …