Stand Biomass at Treeline Ecotone in Russian Subarctic Mountains Is Primarily Related to Species Composition but Its Dynamics Driven by Improvement of Climatic Conditions oleh Pavel A. Moiseev, Frank Hagedorn, Dmitry S. Balakin, Maxim O. Bubnov, Nadezhda M. Devi, Vladimir V. Kukarskih, Valery S. Mazepa, Sergey O. Viyukhin, Arina A. Viyukhina, Andrey A. Grigoriev