Growth pattern ofAbies mariesii saplings under conditions of open-growth and suppression

Abstract

The growth pattern was analysed forAbies mariesii Mast. saplings in the subalpine climax forests of the northern Yatsugatake Mountains, Central Japan. The lateral branches were distinguished from the trunk not only with respect to the branching habits and needle arrangement but also with respect to the distribution of dry matter to needles, the slenderness of shoot-stem and the longevity of needles on them. Based on these differences, the contribution of the trunk and lateral branches to the matter production function of saplings is discussed. The lateral branches showed plastic changes in their growth characters in order to expand and maintain an assimilation system effectively, under conditions of suppression. In addition, the trunk growth was inhibited compared with the lateral branch growth and the apical dominance among lateral branches was weakened in the suppressed saplings. It was concluded that these growth habits resulted in the observed difference in the crown shape of saplings in the different habitats. Arguments are presented regarding the adaptive meanings of such a growth pattern for the shade tolerance and survival of the saplings and for the regeneration of the forest.