DISTRIBUTION OF P, K, CA, MG, MN AND ZN I N THE STEM OF EUROPEAN LARCH AND TAMARACK

In tree stems gradients of nutrient distribution have been reported in many dendrochemistry studies. Most of the patterns of distribution ar e specific to the element and to the species and have been characteriz ed by both increasing and decreasing gradients and by constant concent rations. A ring-by-ring study of nutrients in the stem of 18-yr-old Eu ropean larch (Larix decidua Mill) and tamarack [Larix laricina (Du Roi ) K Koch] enabled the establishment of distribution patterns for P, K, Ca, Mg, Mn and Zn. These distribution patterns were similar to those reported for other species, and the highest concentrations of all nutr ients were observed in the bark. In the xylem, the concentrations of m obile nutrients (P and K) were highest and the concentrations of immob ile nutrients or nutrients of intermediate mobility (Ca, Mg and Mn) we re lowest in the external zone of the xylem while an opposite trend wa s found in the internal zone. Zinc concentrations were similar in both zones. Modification of the distribution patterns of nutrients in larc h following silvicultural treatments or environmental perturbations mi ght be assessed by using the nutrient distribution patterns obtained i n this study as a basis of comparison.