ELEMENTAL COMPOSITION OF SCOTS PINE WOOD, BARK AND NEEDLES IN THE MARI EL FORESTS

The article presents the results of assessment of Scots pine (Pinus sylvestris L.) wood (216 pc), bark (29 pc), needle (127 pc) specimens for the content of 13 chemicals (Ca, K, Mg, Mn, Zn, Fe, Cu, Sr,Ni,Pb, Cr, Co, Cd), which were tested using an AAnalyst 400 atomic absorption spectrometer. The specimens were taken from the stands of different ages, origin and forest-growth conditions in the Republic of Mari El. It shows that the elemental composition of organ tissues of this tree species is its essential ecological and physiological characteristic that represents the peculiarities of the metabolism process in trees and a degree of tree adaptation to the environment. In comparison with the wood, the bark contains seven to eight times more calcium and strontium, four times more cadmium, two times more iron and zinc. As for the content of other elements, the bark does not differ much from the wood, however its ash content is 6.4 times greater. The ash content of the needles is 6.7 times greater than that of the wood, but the needles have a significantly higher concentration of К, Mn, Са, Zn, and in comparison with the bark a higher concentration of Sr, Ni, Pb. The contents of each chemical element in the tissues and organs of pine trees vary within wide ranges due to the environmental factors and individual features of trees. The variation of the Ni content in the wood is the greatest (СV = 92.1%), it is followed by Mg, Pb, Co and Fe (СV = 83%-89%). The Ca and ash contents in the wood vary the least (СV = 38 % and СV = 26.5%, respectively). The bark has the greatest variation of the Cd and Ni concentrations (СV = 172%), and they are followed by Sr, Mg, K (СV = 88%-111%). The Ca, Cu and ash contents in the bark vary the least (СV = 55%-62 %). The needles have the most significant variation in the Sr, Ni, Co contents (СV = 85%-96%) and the least variation in the K and ash contents (СV = 18%-24%). The contents of ash, Ca, Mg, Zn, K, Mn in the Scots pine wood, bark and needles as well as the ratios of К:Mn and Zn:Mn may be used for selection of economically valuable samples along with the other phenotypic characteristics of trees. It is cocluded that the ash composition of tree tissues, especially wood, is not suitable for biomonitoring purposes, since it largely depends on intracenotic factors, rather than technogenic pollution. For this purpose, it is better to evaluate the gross content of chemical elements in the litter and soil of biogeocenoses.