Biomechanical properties of tree saplings and free-standing lianas as indicators of susceptibility to logging damage
Forest Ecology and Management
Liana infestations often impede natural regeneration of commercially important tree species after selective logging of tropical lowland forests. To help elucidate the genesis of these tangles, the biomechanical properties, stem anatomy and resprouting capacities of tree saplings and free-standing juvenile lianas and their responses to mechanical damage typical of selective logging were investigated in Ulu Segama, Sabah, Malaysia. Tree saplings and free-standing lianas were similar in almost all of the parameters compared. Whole-sapling flexibilities, root-stem junction flexibilities, stem taper, and resprouting capacities of tree saplings and free-standing lianas were not different. The maximum fiber-wall thickness, and proportions of vessel lumena, xylem rays and axial parenchyma per cross-sectional area did not differ. Trees and lianas also suffered similar frequencies of damage and mortality after bulldozer passage. Only the elastic resilience of tree saplings and free-standing lianas differed; tree saplings were slightly more resilient than free-standing lianas. These results suggest that the susceptibility and response of tree saplings and free-standing lianas to mechanical damage is similar. An increase in the density of lianas relative to trees was not observed in surviving vegetation on skid trails. This result suggests that liana tangles frequently encountered in selectively logged tropical forest are not the result of differential survival of trees and lianas.