CRECIMIENTO ANUAL EN VOLUMEN Y ESTADO NUTRICIONAL DE Pinus pinaster Ait. EN ASTURIAS, ESPAÑA

Abstract

The relationships among soil parameters, tree nutrition and annual volume increment including bark (AVIC) were examined in six regular stands of a Pinus pinaster plantation located in the central-western area of Asturias (NW Spain). The trees were classified in 10 diameter classes with a difference of 5 cm in width. Three dominant trees of each class were cut and AVIC was calculated. The nutritional analysis was carried out in needle, branches of diameter between 2 and 7 cm; 0.5 and 2 cm; below 0.5 cm and slice obtained from different stem heights. The highest nutrient concentrations were found in the needle, showing deficiencies in P and K content and an Imbalance in the N:P relation that becomes lower progressively in the branches from smaller to bigger diameters. The AVIC was negatively correlated with total N, organic matter content and exchangeable soil Ca and with foliar Ca. The P, K and Mg in the branches of less than 0.5 cm diameter were positively correlated with AVIC, as well as the effective cation exchange capacity, clay content and pH. The results suggest that other factors, like the soil pH, are diminishing Ca assimilation and reveal the importance of fine crown fractions along with the fertilization need to be considered in reforestation programs.