VOLUME GROWTH AND NUTRITION STATE OF Eucalyptus globulus Labill. AND Pinus radiata D. Don IN ASTURIAS, SPAIN

Abstract

Relationships among soil parameters, tree nutrition and annual volume increment with bark (AVIC) were examined for Eucalyptus globulus and Pinus radiata in the central-eastern area of Asturias (NW Spain). For each species, 10 diameter classes with 5 cm of width were considered and three dominant trees between 13 and 52 years of each diameter class and species were cut. The nutritional state was assessed in needles collected from the upper third of the crowns of fell dominant trees, applying the critical level method. The most important deficiencies were in P, K and Mg for P. radiata and in N, P and K for E. globulus. The soils to 0-20 cm of depth were strongly acidic, with high contents of organic matter and high C/N ratios, low contents of exchangeable base cations and low Mehlich 3 available P for both species. The AVIC was positively correlated with Ca content in needles for radiata pine, but it was found a negative correlation between Ca content in needles and available P in soil, and positive with pH. In E. globulus, the AVIC was positively correlated with exchangeable K and available P in soil and foliar Mg, existing a good correlation among the last two ones. Results show the importance of the nutritional balance in the development of both species and reveal the balanced fertilization need.