Multi-stemmed trees in subtropical coastal dune forest: Survival strategy in response to chronic disturbance

Abstract

Abstract Questions: Is multi-stemming a survival strategy in response to chronic disturbance? Is multi-stemming under phylogenetic control? What environmental factors are associated with multi-stemming? When do trees initiate growth of multiple stems? Do multi-stemmed trees have limited stature? Location: Subtropical Indian Ocean coastal dune forest at Cape Vidal in the Greater St. Lucia Wetland Park, northeastern South Africa. Methods: Tree physiognomy and environmental conditions were sampled in 20 transects that were 300 m long and 5 m wide. Results: 38.9 % of trees were multi-stemmed, with no correlation between multi-stemming and taxonomic grouping. The multi-stemming trait was most associated with stem decumbency and substrate erosion and multi-stemmed individuals were less common in protected dune slacks. Trees at Cape Vidal appear to facultatively produce multiple stems from an early stage. There was no trade-off between tree height and stem number. Conclusions: Coastal winds and the unstable dune...