Long-term effects of increment coring on Norway spruce mortality

Abstract

Increment coring of trees is a standard method in dendrochronology, wood anatomy, forest ecology, and forestry. However, increment coring is an invasive method that may result in tree decay and decreased physical stability of the cored tree. The long-term effects of coring on tree mortality are poorly understood for any tree species because long-term data sets are rare. We present results from a 40-year study on the effects of coring on tree mortality in a near-primary Norway spruce ( Picea abies (L.) Karst.) forest in the Swiss Alps (forest reserve Scatlè). In 1965–1966, 551 trees with a diameter at breast height ≥8 cm were cored within a 5.9 ha plot. Following a reassessment of the plot in 2006, we compared the mortality rates of the 551 trees cored in 1965 with those of similar trees from the uncored control group, i.e., trees that were similar in size (diameter at breast height), vitality, and forest layer class. Neither nonparametric tests nor logistic regression models indicate a significant influence of coring on tree mortality. Our results suggest that increment coring does not influence the mortality rate of P. abies within the study region. Additional studies in different environments and on different tree species are needed to evaluate the generality of our findings.