Variation in stemwood nutrient concentrations in Scots pine growing onpeatland

摘要

Radial and longitudinal variation in the nutrient concentrations of Scots pine (Pinus sylvestris L.) stemwood and the effect of fertilization (PK and NPK) were studied on three peatland sites in eastern Finland. The results showed distinctive patterns in longitudinal and radial nutrient concentrations in stemwood. The N, P and K concentrations were highest in the youngest tissues both in the radial and longitudinal directions independent of the site type or fertilization. Ca and Mn accumulated in the older parts of stemwood. Increased N, P, K and Ca concentrations were found 9 yrs after fertilization in the annual rings formed during the first-5-yr period after fertilization. Decreased Mn concentrations were found in the annual rings formed during the 5-and-9-yr periods after fertilization. The results indicate that in the intensive utilization of Scots pine stemwood, e.g. whole stem harvesting instead of stem harvesting to a fixed diameter (7-8 cm in Finland), nutrient loss increases proportionally more than the amount of harvested biomass. The results also imply that this wood contains more undesirable elements, such as K, which may cause problems in wood combustion in power plants, and that fertilization raises these concentrations in wood. However, the concentrations in unfertilized trees were generally at about the same level as in Scots pine stemwood grown on infertile mineral soil sites.