Influence of edaphic factors and tree nutritive status on the productivity of Pinus radiata D. Don plantations in northwestern Spain

Relationships among soil parameters, tree nutrition and site index (SI) were examined in Pinus radiata plantations growing on soils developed from different parent materials (acid schist, granitic rocks and basic rocks) in a climatically homogeneous areas of NW Spain. Soil depth, in association with soil water balance and nutrient store, had the greatest influence on the productivity of these plantations. Although foliar N and K were sufficient in every stand studied, widespread deficiencies of P, Mg and, to a lesser extent, Ca were diagnosed. Foliar concentrations of Ca and Mg were positively correlated with soil nutrient concentrations. The main factors affecting site quality were identified with principal component analysis. The SI was positively correlated with foliar P concentrations, soil depth and pH, and negatively correlated with soil total N. Approximately 60% of the observed SI variation was accounted for by these soil properties. The results suggest the importance of site selection and fertilizer treatments in reforestation programmes. (C) 2002 Elsevier Science B.V. All rights reserved.