geosciences Article The Influence of Relief on the Density of Light-Forest Trees within the Small-Dry-Valley Network of Uplands in the Forest-Steppe Zone of Eastern Europe Pavel Ukrainskiy 1, Edgar Terekhin 1, Artyom Gusarov 2 , Eugenia Zelenskaya 1 and Fedor Lisetskii 1,* 1 Federal–Regional Center of Aerospace and Surface Monitoring of the Objects and Natural Resources, Belgorod National Research University, 308015 Belgorod, Russia;
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[email protected]; Tel.: +7-4722-301370 Received: 29 August 2020; Accepted: 21 October 2020; Published: 24 October 2020 Abstract: An active process of the invasion of woody vegetation, resulting in the formation of light forests, has been observed in predominantly herbaceous small dry valleys of the forest-steppe uplands of the East European Plain over the past two decades. This paper investigates the spatial features of the density of trees in such light forests and its relationship with relief parameters. The Belgorod Region, one of the administrative regions of European Russia, was chosen as a reference for the forest-steppe zone of the plain. The correlation between some relief characteristics (the height, slope, slope exposure cosine, topographic position index, morphometric protection index, terrain ruggedness index, and width and depth of small dry valleys) and the density of light-forest trees was estimated. The assessment was carried out at the local, subregional and regional levels of generalization.