Relationships between Forest-Stand Parameters and Sentinel-2 Spectral Reflectance in the Central Russian Forest-Steppe

The article presents results of analysis of the relationships between forest-stand parameters (age, height, growing stock volume) and Sentinel-2 spectral reflectance in the Central Russian forest-steppe. The age of oak forests is inversely related to the reflectance in all spectral ranges. The strongest relationship between age and spectral response was found in the red and short wave infrared (SWIR) bands. The relationships between forest age and reflectance in all Sentinel-2 bands are curvilinear and are most reliably approximated by a logarithmic curve. The height and growing stock volume of oak forests are also in inverse, curvilinear dependence with spectral reflectance in all ranges. The relationship of the height of oak forests with the spectral response is stronger than with the age of the stand. Ash-dominated forests and oak-dominated forests are characterized by similar relationships between age, forest height, and spectral reflectance. For the ages and heights of forests dominated by ash, the strongest relationship with the spectral reflectance values was also found for the Sentinel-2 SWIR bands.