Dynamics of Pinus sylvestris L. population structure and regeneration characteristics in coniferous broadleaf forests of the Middle Volga Region (Republic of Tatarstan, Russia)

Kazan Federal University, 5, Tovarisheskaya str, Kazan, 420097, Russia

^* Corresponding author: busmanof@kpfu.ru

Abstract

Pinus sylvestris L. in the Middle Volga region is found in the boreal ecotone in areas of coniferous-broadleaved forests located on the southern border of the forest zone. The assessment of abundance and age structure c 2004-2023 reflects the fluctuating dynamics of the species on the territory of the Volzhsko-Kamsky Reserve, where anthropogenic factors are minimized and the effects of climatic and abiotic factors are revealed. In general, a positive number growth is noted for 20 years. According to the results of determination of abiotic conditions of sites of regeneration niches we found out that P. sylvestris regeneration is mainly carried out in conditions of open “windows” of canopy or on the top of windfall-soil microsites, very rarely in gaps with some shading by crowns. According to the results of the assessment of the undergrowth number dynamics in 2022-2023, drying of seedlings and juvenile individuals from May to October was noted, where the percentage of surviving P. sylvestris in 2022 was 86%, in 2023 – 34%. The relationship between the number of pregenerative individuals of P. sylvestris and climatic factors from 2004 to 2022 was determined, a positive dependence on the average temperature of the period May-September (0.69) and December-April (0.62) of the current year was revealed. Negative dependence of the undergrowth number with the sum of precipitation of May-September of the current year (-0.8) and, on the contrary, positive dependence with the sum of precipitation of the previous year (0.68) was noted.