Evaluation of Seasonal Dynamics of Spectral Brightness Coefficients of Predominant Species in the Penza–Kamensk State Protective Forest Belt Using Remote Sensing and Field Research

Abstract—To improve climate conditions, preserve agricultural crops, and protect against deflation, eight state protective forest belts (SPFBs) with a total length of 5320 km were designed 76 years ago. Currently, up-to-date data on the state of the SPFBs are not publicly available, so determining the current state of the protective forest belts based on remote sensing data is relevant. The purpose of the study is to determine the main changes in the spectral brightness coefficients (SBCs) of the predominant species in the Penza–Kamensk SPFB based on remote sensing data and inventory work. The object of the study is the Penza–Kamensk SPFB, which runs through Volgograd oblast. The design boundaries of the studied object are mapped using ultra-high-resolution data. The safety of the Penza–Kamensk SPFB is determined based on high-resolution data from the Sentinel-2 satellite using the NDVI vegetation index. During the laboratory studies, 6949.62 ha of the projected area of the SPFB are allocated, the area inside the contours is 6317.91 ha, and the overall preservation of the studied object is 90.91%. During the inventory study, more than 59 different types of combinations are described to determine the species composition, the average height of the stands is calculated, the density of the plots is calculated, and the quality classes are assigned according to the Orlov table. As a result of the inventory, it is determined that the predominant species are English oak (Quercus robur L.), Pennsylvania ash (Fraxinus pennsylvanica Marsh.), and Elm (Ulmus L.), for which the SBCs are calculated. The results demonstrate a significant difference between the coefficients of the predominant tree species from channel 6 to 8A; high values are observed in sections with a pure elm species composition and a composition mixed with it. Based on the analysis data, the minimal SBC values are obtained on plots with pure ash stands.