REACTION OF MIDDLE-AGED PINE STANDS IN KRASNOYARSK FOREST-STEPPE TO NITROGEN FERTILIZERS AND THINNING

Based on the analysis of the wood increment dynamics in the middle-aged pine forests of the Krasnoyarsk forest-steppe of various structure, formed through thinning of different intensities and the introduction of various doses of mineral fertilizers (carbamide, 46 % of the active substance), the regularities of changes in the current annual increment were established. A model allowing assessing the trends in increment with age and density of stands growing both without and with the use of fertilizers has been proposed. Data are presented indicating that in the conditions of the Krasnoyarsk forest-steppe, due to the application of fertilizers, the current annual increment in pine plantations can be increased by 1.2-6.8 m³/ha compared to the reference site. Differences in the response of stands to fertilization in the first five years and the next three years were revealed it has been found that the current annual increment increases significantly starting from the sixth year after fertilization. The density-age optima of the productivity of pine stands, providing a multiple increase in the increment of managed stands as compared to the reference site were established. The obtained knowledge is the theoretical basis for the implementation of a model of intensive use and reproduction of forests in the best forest growing conditions, and will also be useful in creating carbon farms, which main purpose is to reduce the carbon footprint of industrial enterprises.