Dynamics of Biometric and Carbon Indicators of Pine Plantations Growing on the Abandoned Farmlands of the Krasnoyarsk Forest-Steppe
Authors:   Reshetnev Siberian State University of Science and Technology, Vais Andrey A. , Varaksin Gennadij S. ,   Sukachev Institute of Forest of the Siberian Branch of the RAS – Division of Federal Research Center “Krasnoyarsk Scientific Center of the Siberian Branch of the RAS”, Mamedova Sevinch K. ,   Reshetnev Siberian State University of Science and Technology, Andronova Alina A. 
Published: December 2024

Today, the overgrowth of woody and shrubby vegetation on former agricultural lands is a serious problem. The aim of this research has been to investigate age-related changes in the forest inventory indicators of forest stands on abandoned farmlands. Taking into account the temporal factor when monitoring the carbon budget allows identifying a number of processes in the dynamics of carbon sequestration that cannot be estimated in a single study. To address this issue, data from permanent sample plots have been analyzed in 2011 with repeated measurements in 2023. The sample plots are located on the abandoned farmlands on the border of the Krasnoyarsk forest-steppe area. The dynamics of the process of Today, the overgrowth of woody and shrubby vegetation on former agricultural lands is a serious problem. The aim of this research has been to investigate age-related changes in the forest inventory indicators of forest stands on abandoned farmlands. Taking into account the temporal factor when monitoring the carbon budget allows identifying a number of processes in the dynamics of carbon sequestration that cannot be estimated in a single study. To address this issue, data from permanent sample plots have been analyzed in 2011 with repeated measurements in 2023. The sample plots are located on the abandoned farmlands on the border of the Krasnoyarsk forest-steppe area. The dynamics of the process of overgrowth and development of plantations has shown that as the abandoned farmlands form, in addition to the dominant Scots pine (Pinus sylvestris L.), silver birch (Betula pendula Roth) and aspen (Populus tremula L.), Siberian larch (Larix sibirica Ledeb.), Siberian spruce (Picea obovata Ledeb.) and goat willow (Salix caprea L.) are also found. The dynamic process of pine abandoned farmlands has been established over a period of 15 to 27 years after land abandonment. The mixed plantations of various successional origins have ranged in age from 10 to 30 years old. Various processes have been observed in the research plots in terms of changes in the density of abandoned farmlands (overgrowth, thinning). The reforestation of abandoned farmlands occurs from the forest border and at a distance of up to 50 m continues after 30 years. The abandoned farmlands are characterized by various forms of overgrowth: clumps, biogroups, complete and by single trees. The average quantitative assessment has shown that that the most intense changes in height, diameter, height to the crown base, height to the largest crown width, and crown diameters have occurred in the test area where the minimum density has been observed, which has been decreasing dynamically. In the plot with the maximum density, morphological indicators have been characterized by an average increase. Minimal changes have been recorded in the sample plot where the density has increased significantly over 12 years. The growth rate of trees of the same diameter in height has been greater in 2023 compared to 2011. It is possible that this has been influenced by a combination of external and internal factors, including climate change. To assess the carbon productivity of forest stands growing on the abandoned farmlands, it is advisable to use regression equations developed for a specific area. The results of the study of the dynamics of carbon sequestration by young forests growing on the abandoned farmlands indicate the feasibility of using postagrarian lands for the implementation of forest climate projects.