Abstract
<jats:p>Significant areas of the forest fund are occupied by mixed stands of different origins due to unseasonable tending and its low quality. In order to form coniferous stands with a slight admixture of deciduous trees, it is necessary to change their species composition and density. Carrying out thinning (release cuttings and forest clearings) requires significant costs and labor intensity. The most promising option for eliminating competition between deciduous trees in mixed stands is the herbicide injection into the trunks of undesirable deciduous trees. This technology combines high silvicultural and commercial efficiency with environmental safety. Guidelines for herbicide injection have not been updated for more than three decades and require significant adjustments. The research aimed at the regulation improvement of the forest stands composition and density by injecting herbicides and their mixtures into the trunks of deciduous trees while reducing the chemical and toxic load on forest ecosystems. Research objects were individual trees of grey alder (Alnus incana (L.) Moench) and aspen (Populus tremula L.) of vegetative origin in the pole stage in mixed plantations. The studies revealed the effective action of the Tornado herbicide preparation and its mixture with the Arbonal herbicide in low doses on grey alder and aspen with complete suppression of their vegetative capacity. The Arbonal alone acted somewhat slower than the Tornado, but showed high efficiency in the vegetation season following the treatment. The data obtained indicate the prospects of the recommended options for the herbicides application to suppress deciduous species common for the taiga zone. Cost-effectiveness analysis of the proposed technology showed that the total financial costs are 16–21 times lower compared to the basic technology using mechanical means of eliminating undesirable vegetation.</jats:p>