JoAnne L. Oliver and Kenneth M. Klemow 1988. ANNUAL GROWTH DECLINE IN RED SPRUCE (PICEA RUBENS) IN NORTHEASTERN PENNSYLVANIA. Contributed poster: Pennsylvania Academy of Science meeting. Abstract: Journal of the Pennsylvania Academy of Science 62:55.
Recent studies of annual growth in red spruce in the eastern United States have shown the species to be suffering a widespread decline since the early 1960s. Acid precipitation and natural senescence have both been implicated. Annual growth patterns of Picea rubens were examined by analyzing increment core samples taken from ten individuals growing in a natural population at an elevation of 550 m, located 7 km south of Wilkes-Barre, PA. Almost all of the trees exhibited a decline since the early 1960s; a pattern consistent with that found on other sites along the eastern United States. The decline was evident both in trees growing alone and in those growing adjacent to other trees, suggesting that competition was not a factor. Moreover, plants aged 40-70 years exhibited decline, as did those aged >80 years. Thus, senescence did not contribute to decline in these populations. Acid precipitation remains a likely possible explanation for the decline.