GROWTH AND PRODUCTIVITY OF PINE AND LARCH STANDS UNDER CONDITIONS OF URBAN ENVIRONMENT

Abstract

Introduction. Urban forests are of great ecological value as the facilities for maintaining a favorable environment for the life of citizens. Development of industrial production, and increased traffic flows lead to air pollution in the cities, which contributes to decrease in productivity of stands, increase in the decline of stands, and decrease in growth of stands. The aim of the work is to analyze the growth and productivity of pine and larch stands under different anthropogenic influences and to develop the recommendations for increasing their stability and durability. Materials and methods. The data from the inventory of permanent trial plots at the Experimental Forest District of the RSAU-MTAA and other forest areas of the city of Moscow and Moscow region were the materials for the study. The alignment of the dependence of the average heights on age was carried out using the growth function of Mitcherlich. The stock of stands was calculated by multiplying the sum of the cross-sectional areas by the form height. The amount of oxygen was calculated through pure primary phytomass production. The phytoncidal activity of pine and larch stands was determined conditionally on the basis of generalization of data from literature sources. Results. The growth of stands by the medium height in the trial plots does not correspond to the bonitet scale: first, the bonitet class is upgraded, and then it is declined. A complex of unfavorable factors leads to a decrease in productivity and durability of pine stands, and this effect is most pronounced from the center of the forest to its periphery and from the side of prevailing winds. Among the pine stands, forest plantations with the density of planting of 32000 pieces per 1 hectare showed the greatest stability and productivity. High stability is shown by larch stands, which gives them an advantage over pine trees when used in urban landscaping. Conclusion. Mixed pine-larch plantations with the underwood of broad-leaved species, which improve the performance of plantations and improve protective, sanitary-hygienic, recreational functions of urban forests,  are promising in urban conditions. Pine compensates low larch productivity in youth, and by the time of complete destruction of pine forest generation, larch forms the most productive stands. Besides, the larch stand has an advantage in producing the oxygen, and most part of volatile compounds is released by the pine stand.