This paper presents results of analyzing the second half of the 20th–early 21st century changes in lateral spatial structure of Larix sibirica Ledeb. population in the upper treeline ecotone located on the Rai-Iz massif (Polar Urals, Russia). The GIS layers characterizing distribution of Siberian larch trees and undergrowth together with their crowns was produced for a 7.32 square kilometer area based on aerial images recognition. Using statistical models, we assessed probabilities for assigning trees to age intervals of 1–10, 11–40, and 40+ years based on the average radius of tree crown projection. These maps and layer showing locations of trees that grew in the upper part of the ecotone, and died during the Little Ice Age, allow for assessing specifics of forest cover proliferation at different parts of upper treeline ecotone, and comparing current location of the trees with one from the past. The proposed method for probability-based recognition of Siberian larch tree generations in the upper treeline ecotone using average crown radius can be used to reconstruct time and spatial forest dynamics at the upper growth boundaries for time spans up to 100 years and more.

The restoration of technogenically-disturbed territories represents one of the most critical ecological and forestry challenges, particularly in regions with a high degree of anthropogenic impact, such as the Ural region. This study ex-plores the possibility of using amorphous silica as a fertilizer to increase the efficiency of forest ecosystem recovery on reclaimed lands. Amorphous forms of silica exhibit multifunctionality and can exert both direct impacts on plant resili-ence to various stresses and indirect influences by improving soil properties and enhancing its fertility. The objective of this investigation is to evaluate the effect of amorphous silica on the growth of Scots pine (Pi-nus sylvestris L.) and Siberian spruce (Picea obovata Ledeb.) seedlings in a reclaimed granite quarry. To accomplish this, sites were chosen within the educational-experimental polygon for land reclamation of disturbed lands at the Ural State Forest Engineering University, situated at the Isetsk granite quarry in the Sverdlovsk region. The soil analysis revealed a moderate soil acidity level (pH 4.92±0.12) and low concentrations of water-soluble potassium and nitrate nitrogen in the soils of the reclaimed site, along with a relatively elevated content of available phosphorus. These findings suggest the need for applying fertilizers and soil amendments during the establishment of forest plantations. As part of the study, works were carried out on the application of amorphous silica, as well as an analysis of its effect on the growth of tree seedlings. The findings from this research will broaden our comprehension of the efficacy of silicon-based fertilizers under forestry reclamation conditions and propose novel strategies for restoring ecosystems in technogenically disturbed areas