Phytocenotic and Biotopic Parameters Affect the Condition of European Spruce Cultures during the Establishment Stage in the South-East of the Leningrad Region

In the Boksitogorskiy district of the Leningrad oblast, the study was conducted regarding the influence of phytocenotic parameters (crowns density, height, herbage density, moss cover) and biotopic parameters (illumination, acidity, moisture and soil richness) on the morphometric parameters and vitality of European spruce (Picea abies (L.) H. Karst.) BRT (bare root trees) and RBT (root-balled trees) seedlings during the establishment phase under contrasting growing conditions: under the sparse aspen canopy left in clearings and in open spaces, outside the influence of tree crowns. The positive effect of undercanopy cultivation on the safety and viability of seedlings of both types has been statistically proven; with RBT seedlings having the best indicators of vitality and growth along the main axis. However, the herbaceous layer’s height and density under these conditions adversely affected the branching of seedlings. Unlike the undercanopy conditions, when growing in the open, the condition of seedlings was more susceptible to the influence of abiotic factors. Under these conditions, a close positive correlation was found between the viability of seedlings with BRT and the main soil parameters (humidity, acidity, and nitrogen supply). Due to the better illumination on plots without canopies, seedlings with BRT had consistently high growth rates along the main axis. Under these conditions, the grass cover at the stage of spruce establishment was found to have a protective effect, maintaining a more optimal moisture regime and shading the seedlings. The practicality of using the RBT cultures in open spaces was still substantiated, since they were less susceptible to the negative influence of factors.