Home – Home – Jornals – Siberian Journal of Forest Science 2017 number 1

Analyzed and generalized were the results of prolonged (10-25 years) monitoring of condition pine Pinus sylvestris L. forests affected by technogenic pollution and high recreation load in the South Prebaikalia. The results show that both factors have similarity in the stress effect on pine tree-stands, as confirmed by alteration in morphometric parameters of tree assimilating phytomass, decrease in photosynthetic pigments level, as well as by disturbance the nutrient elements proportions in the needles. As tree crown defoliation level reaches 65-70 %, the morphometric parameters for shoots and needles are found to decrease the background level by in 1.3-4.5 times. Under technogenic pollution, the needles’ chlorophylls sum was reduced 2.8-3.5 times, level of carotenoides - to 3.9 times maximum in comparison with the background needles while under high recreation load the green pigments content was reduced 1.9-5.7 times, carotenoids content - to 5.5 times. There is a imbalance in quantitative proportions between nutritional elements under any type of stress, N : P : K proportion changes due to increase of nitrogen level and reduction of phosphorus and potassium level. Index of tree-stand vital condition was calculated on the basis of the representative parameters to analyze the long forest dynamics. Significant reduction was shown in the index in the present time and correspondingly the obvious tendency to pine forest decline in the territories polluted by Irkutsk, Shelekhov, and Angarsk-Usolie industrial centers. At the same time near Cheremkhovo and Sayansk-Zima centers there are not heavy changes in the forest’s condition; during long time a middle level of weakening is registered but in the distance 20 km - a low level of weakening. In the territories characterized by a high recreation load, a sharp trend to declining pine tree-stands vital condition was found, and most clearly it is expressed in the towns of Khuzhir (Olkhon island) and Listvyanka, where there is a particularly high soil disturbance. Based on these results a schematic map has been developed to show the identified problem areas with revealed significant tendency to decline of the vital condition the pine tree-stands in the contemporary period.