Creation of Forest Cultures of Crimean Pine (Pinus pallasiana D. Don) on the Hilly Sands in the Steppe Zone of Russia

Forest crop cultivation of Crimean pine (Pinus pallasiana D. Don) was implemented in 2009–2020 on sandy and sand included soils in the steppe zone of the European part of Russia. During the analysis of the reasons for the low efficiency of reforestation, the authors proposed the hypothesis that the rules of planting recommended for Scots pine relative to the depth of rooting may not be acceptable for Crimean pine. The purpose of the work is to substantiate the necessity and the most optimal value of deepening the root collar of Crimean pine seedlings on hilly sands. Experimental forest cultures were planted in 2017. The depth of the plant collar relative to the soil surface was tested at 0, 2, 4, 6 cm, and until the seedling’s foliated part. The reference group was created by machine cultivation, which required a rooting depth of 6 cm or more. In the case of hand cultivation, the variants with planting depths of 2 and 4 cm had the highest rates of plant survival (94.2–94.6 % in the first year), plant safety (67.0–94.6 % in the fourth year), and their most even distribution over the silvicultural area (variation coefficient (υ) at 6.6–28.8 %). The lack of deepening and very deep planting by 6 cm led to a decrease in plant survival and preservation by 7.6–18.6 % with an increase in the range of the variation coefficient (υ, 10.2–60.6 %). The mechanized planting with a root collar depth over 6 cm gave the lowest number of preserved plants (58.4 % in the first year, 32.7 % in the fourth year), and the greatest range for the variation coefficient (υ, 30.5–70.1 %). An analytical equalization of the density of age dynamics showed that the predicted density would not reach the normative value with low and very deep planting. The established statistically significant differences in the survival rate of forest cultures throughout the observation period (tf = 2.12–4.38> t05 = 2.12–2.45) indicated the expediency of deepening the root collar. The optimal value is 2–4 cm, but until the seedling’s foliated part. For citation: Turchina T.A., Bannikova O.A. Creation of Forest Cultures of Crimean Pine (Pinus pallasiana D. Don) on the Hilly Sands in the Steppe Zone of Russia. Lesnoy Zhurnal = Russian Forestry Journal, 2023, no. 4, pp. 76–92. (In Russ.). https://doi.org/10.37482/0536-1036-2023-4-76-92