Changes in the Structure of Coniferous Forests Within the Broad-Leaved Coniferous Forest Zone in PreUrals (Russia) Based on Data from 50-Year Direct Observations

The growth and development of individual trees as well as the interactions between various tree species determine the structure and composition of forests. Evaluating the processes of forest formation is made possible by examining the dynamics of alterations in the composition and structure of forests. To evaluate the changes in forest structure and composition over a 50-year period, five types of coniferous forests (spruce, fir, spruce-fir, pine, and larch forests) within the broad-leaved coniferous forest zone in the PreUrals were studied. Data from the 1971 forest inventory (for fir forests in 1984) and the 2020 forest inventory were used as the basis for this investigation. Three permanent trial plots per type of coniferous forest totalling fifteen were laid out. Over a 50-year period, conifer forests have grown and developed successfully. Coniferous forests are undergoing changes in composition and structure. New spruce and fir generations have arisen, allowing stands in all types of coniferous forests to develop sustainably. The diameter of the trees differs significantly. In pine and larch forests, pine and larch trees are gradually replaced by spruce. This is because spruce can grow under various environmental conditions. A high threshold of sustainability is indicated by the overall pattern of tree difference in coniferous forests for the viability of natural coniferous forest ecosystems.