Wood conductive strategy of Nothofagus alpina (Nothofagaceae), basin Lácar, Neuquén, Argentina

Abstract

The hydraulic architecture of wood is one of the trees strategies of adaptations to their environment. The economic and ecological value of Raulí (Nothofagus alpina) in Argentina makes it necessary to generate knowledge that would contribute to an estimation of its adaptation capacity to variable growth conditions. The pattern of variation of conductive elements of the wood was determined and its anatomy was interpreted as adaptive strategy. Specimens of Lácar basin, Neuquén, Argentina, were studied; from them, slices were cut at 1.3 m height from the ground. The North orientated radius from each section was used for the extraction of samples every ten growth rings for the preparation of microscopic slides and macerations. Diameter and pore number per square millimeter, length of vessel elements and fibers, wall width and total diameter of fibers were measured, and net pore area, eco-anatomic vulnerability and pore grouping indexes were calculated. The major source of variation of the analyzed characteristics was the tree, related to age. Vulnerability (0.47) and pore grouping (1.71) indexes indicated a low vulnerability to cavitation. The efficiency in wood conduction significantly increased with age in detriment of conductive security. Conductive and mechanic resistance variables were shown to be highly correlated (R² = 0.71), suggesting connected functioning, adding conductive security to the wood.