The effect of age on height growth in even-sized saplings of Fagus sylvatica L.

Abstract

After controlling for the effects of size and light, partial regression revealed that height growth of common beech saplings was negatively affected by sapling age. Common beech (Fagus sylvatica L.) saplings were studied along gradients of light availability (4–82 % of full sunlight), initial size (9–290 cm), and age (2–25 years) to examine the interactive effect of these variables on saplings’ annual height growth. Although age was non-significant as a main effect in a linear model, sapling age had a significant interaction with the other variables. After controlling for the effects of size and light, partial regression revealed that height growth was negatively affected by sapling age. Observed growth decline in older common-sized saplings may be explained not as effect of age per se, but as indirect age-related effect probably induced through plastic response of saplings to past growth conditions.