Temporal variation in nutrient concentrations of Pinus sylvestris needles
1990
Helmisaari, H.S. (Skogsforskningsinstituet, Vantaa (Finland))
Temporal variation in nutrient concentrations of Scots pine (Pinus sylvestris L.) needles was studied during a three-year period in three stands of differing stages of development. Concentrations of N, P and K varied significantly between years; this variation was related to differences in needle dry weight. Concentrations of all measured nutrients (N, P, K, Ca, Mg, Mn, Cu, Zn, Fe, B) and Al varied between seasons: this variation was related to nutrient mobility and the annual physiological cycle. Concentrations of the mobile nutrients N, P and K decreased in spring and early summer during shoot and needle elongation and increased in late summer and autumn during needle senescence and litterfall. Concentrations of Mg, Cu, Zn and B followed somewhat similar patterns. The poorly mobile nutrients Ca, Mn and Fe accumulated gradually in needles during each growing season. Needle nutrient concentrations were stable during the nonactive period.
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