Nutrient concentrations in foliage,litter and soil in relation to wood production of 7- to 15-year-old Pinus radiata in Victoria,Australia

We report the changes in nutrient concentrations in unthinned stands of Pinus radiala aged 7, 11 and 15 years old planted across 11 soil types. Correlations between nutrients in foliage, litter and soil (0–20 cm and 20–40 cm) indicated that the links between the components increased with stand age for N and P. Litter weight on the forest floor was dependent upon standing wood volume, and the mass of nutrients in the litter, particularly N and Ca, increased concomitantly with wood volume. The litter layer provided a large pool of nutrients which was related to nutrient concentrations in the surface soil. Concentrations of N and P declined in foliage with age concomitantly with an increase in the amounts immobilized in litter. However, wood volume at age 15 years was positively correlated with foliar N and P concentrations, and the rate of decline in foliar N or P was not correlated directly with a decrease in the rate of wood production.