© 1992 Heron Publishing—Victoria, Canada
Nutrient retranslocation within the foliage of Pinus sylvestris
Heljä-Sisko Helmisaari
Finnish Forest Research Institute, Department of Soil Science, P.O. Box 18, SF-01301 Vantaa, Finland / Received January 18, 1990
Summary
During the period 1983–1987, retranslocation of N, P, K, Ca, Mg, Mn, Zn, Fe, B and Al within the foliage of Scots pine (Pinus sylvestris L.) was studied in sapling, pole-stage and mature stands in eastern Finland. Needle concentrations of the mobile nutrients
N, P, and K varied seasonally because of retranslocation. In unfertilized plots, needle contents of N, P and K decreased 62–92%
during senescence and needle dry weight decreased 19–51%. In some years, needle contents of Ca, Mn, Zn, Fe, B and Al increased
during senescence. Retranslocation was more efficient from needles with greater dry weight. In the fertilized, pole-stage
stand, needle dry weight did not decrease at senescence four years after fertilization and nutrient content decreased less
than in the other years. In the mature stand, there were no clear differences in needle dry weight and nutrient changes during
senescence between years or between unfertilized and fertilized plots.
