Influence of trunk forking on height and diameter growth in an even-aged stand of Nothofagus pumilio

Abstract

In many tree species, trunk forking plays a major role in crown construction, and stands out as an indicator of the architectural transition between juvenile and adult trees. We aimed to evaluate the effects of trunk forking on height and diameter growth of Nothofagus pumilio trees in an even-aged monospecific stand in northern Patagonia, Argentina. We used cataphyll scars and ring-width measurements to compared yearly increments in mean trunk length and diameter of trees with forked and unforked trunks. After approximately 50 years of growth, trees with a forked trunk had reached larger radial growth than unforked trees, but there was no difference in height between the two groups. The larger trunk volume of forked trees suggests that they may have a competitive advantage over unforked trees; trunk forking could therefore, influence dominance/suppression relationships. Our results suggest that morphogenetic processes associated with trunk forking influence the establishment of size hierarchies in dense stands of Nothofagus pumilio.