SPATIAL AND AGE DEPENDENT PATTERNS OF GROWTH IN NEW ENGLAND BLACK BIRCH

Abstract

Ring width chronologies from 127 black birch trees in the northeastern United States were used to study age dependent and spatial patterns in growth. The trees sampled show no evidence for increasing stability of growth with age, as measured by the year‐to‐year variance and autocorrelation. Large scale spatial patterns were studied using trees sampled from five localities separated by distances of 40 km to 325 km. Cluster analysis based on the last 30 years of growth is able to assign a tree to its locality of origin with approximately 80% accuracy. However, the degree of correlation between these chronologies does not decline as a function of the distance of separation of the localities. Fine scale patterns were studied using chronologies from 46 birches lying within a 50‐m x 60‐m plot. Strong neighborhood effects could not be detected in the rate of growth, the variance of growth, or the between‐tree correlation. Dry‐site trees, however, were found to be growing significantly faster and with less variability than wet‐site trees. The results suggest that very local factors are important determinants of growth and dominate the environmental structure perceived by mesic forest trees.