Fenología del anillo de crecimiento de Pinus uncinata Ramond y Pinus sylvestris L. en un gradiente altitudinal en los Pirineos Centrales

Abstract

In this study, we describe tree-ring growth and structure of Pinus uncinata Ram. and Pinus sylvestris L. along an altitudinal gradient in the Central Pyrenees. We measured monthly ring width increase and the number of cells added during 1993. Both species formed most of the ring from mid june to mid July 1993. Latewood development -formation, darkening and lignification of cell walls- starts in July and ends in October. The ring begins before its development in P. sylvestris than in P. uncinata that lives at higher elevation. P. uncinata formed narrower rings with less cells and greater color heterogeneity in the latewood than P. sylvestris. There is a high variability between trees in the earlywood and latewood cells position in the ring. The different phenological patterns of tree-ring growth along the selected altitudinal gradient could be partially explained by the influence of different climatic conditions, mainly thermic.