Crown structural properties, wood density, and liana load: influence on growth and mortality in subtropical forests

Abstract

Wood density (WD) and other wood mechanical and structural properties may have a strong functional relationship with demographic patterns and allometry of trees. We analyzed the influence of WD, structural properties, architectural traits and community level attributes on growth rates (GR) and mortality modes of canopy tree species in a subtropical forest of Argentina. Stem WD, and WD, strength, stiffness, toughness and hardness of branches were measured in 10 canopy species. Also, architectural traits and liana load were determined. Strength and hardness of branches were linearly correlated to branch WD, and GR were linearly correlated to stem WD across species. At individual level, trees with greater hardness and toughness in branches died mostly uprooted and trees with greater branch stiffness and susceptibility to colonization by lianas were mostly broken. At community level, the suppressed trees died mostly broken. The dominant trees with high local tree density died mostly broken whereas more isolated trees died mostly uprooted. Mortality modes were determined by mechanical properties, but also by community properties, such as liana load, crown canopy position and number of neighboring trees. Other biophysical traits beside WD are important explanatory variables when dry wood is used to describe functional characteristics of trees.

Wood density and tree size used as cues to locate and excavate cavities in two Colaptes woodpeckers inhabiting a threatened southern temperate forest of Argentina

“…The density of the wood could vary between 0.1 (softest) and 1.5 g/cm 3 (hardest) (Chave et al 2009). In a subtropical forest, where wood density ranged from 0.36 g/cm 3 to 0.73 g/cm 3 , wood hardness ranged between 615 N and 4365 N (Rodríguez et al 2021). Moreover, Lorenz et al (2015) reported values between 0.0 and 6.6 Nm for woodpeckers cavity-trees wood hardness and between 0.0 and 27.6 Nm for random trees wood hardness in a temperate forest of North America.…”