Biometric indicators of Mongolian oak plus trees seedlings (Quercus mongolica Fisch. ex Ledeb.)

The aim of the study is to determine the variability of biometric parameters of six-year-old Mongolian oak plus tree (Quercus mongolica Fisch. ex Ledeb.) seedlings depending on seed origin. The studies were conducted at the Gorno-Tayezhnoye Forest Nursery, a branch of the V.L. Komarov Mountain Taiga Station, Far Eastern Branch of the Russian Academy of Sciences, located in the village of Gorno-Tayezhnoye, Ussuriysk Urban District, Primorsky Region (43°41′37″ N 132°09′10″ E). The soil in the experimental plot is brown podzol with a pronounced clay structure, which transforms into a meadow-brown variant in the lower part. The experiments were carried out in 2023–2024. This study conducted a comparative analysis of biometric parameters (height, annual growth, and trunk diameter) of six-year-old seedlings grown from seeds of various origins using a standard method. The highest average height values were found in seedlings whose seeds were collected from the Verkhnussuriysk Station (VUS) (139 cm) and from the vicinity of Ussuriysk (135 cm). The most intense annual growth was observed in seedlings with VUS, where the ave-rage value reached 58.1 cm, which significantly exceeds the values in other locations. However, the spread of values is also significant (V = 39.9 %). The largest average diameter was noted in seedlings grown from seeds collected in the vicinity of Ussuriysk (4.0 cm) and VUS (3.3 cm). Significant differences in height were noted among specimens with VUS, Livadia, and the vicinity of Ussuriysk (F = 3.12; p = 0.05), indicating a statistically significant difference between the groups. However, differences in trunk diameter were insignifi-cant (F = 1.58; p = 0.22). This indicates different abilities of plus tree progeny to ensure high growth rates in the initial stage. The data obtained can serve as a basis for further research aimed at optimizing Mongolian oak cultivation. In the future, it would be advisable to continue monitoring the growth of progeny of plus oak trees.