Local-scale drivers of multi-stemmed tree formation in Acer,in a temperate forest of Northeast China

Acer is an important genus in temperate forests in Northeast China. Individual Acer trees can re-sprout from the root collar and can occur in clonal units, either as a single-stemmed or multi-stemmed tree. However, the factors that induce multiple-stems in Acer remain only partly understood. In this study, we determined the relative importance of abiotic and biotic variables in driving the production of multiple-stems in this genus, within a 25-hm² experimental forest dynamics plot in Changbaishan (CBS) temperate forest. We used generalized linear mixed models to perform analyses at two levels (community- and species-level). We found seven Acer species in total within the plot, where they form a key part of the forest community. Our results show that abiotic factors play a more important role in producing multi-stemmed trees at the community level in CBS. At the species level, the relative importance of different factors varied among species. Shrub species tended to have a higher frequency of multi-stemmed trees under stressful conditions, whereas tree species tended to have more multi-stemmed trees in more suitable habitat. Our results indicate that the relative importance of different factors influencing the frequency of multi-stemmed individuals in Acer differs at the community and species level in the temperate forest.