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This paper reports on measured carbon stocks in the forests of two treeline ecotones of the Ural region where climate change might improve growing conditions. The first is an alpine ecotone that is represented by an altitudinal gradient of the spruce-dominated forests on the Western slope of the Tylaiskii Kamen Mountain (Western part of the Konzhakovskii-Tylaiskii-Serebryanskii Mountain system, 59 0 30'N, 59 0 00'E), at the alpine timber line that has risen from 864 to 960 m above sea level in the course of the last 100 years. The second is an arctic ecotone in larch-dominated forests at the lower course of the Pur River (67 0 N, 78 0 E), at the transition zone between closed floodplain forests and open or island-like communities of upland forests on tundra permafrost. According to our results, there are large differences in the carbon of the aboveground biomass of both ecotones across environmental gradients. In the alpine treeline ecotone, a 19-fold drop of the carbon stocks was detected between the lower and higher altitudinal levels. In the arctic ecotone the aboveground biomass carbon stock of forests of similar densities (1300 to 1700 trees per ha) was 7 times as much in the river flood bed, and 5 times as much in mature, dense forests as the low density forests at higher elevations.

This paper presents the results of the statistical analysis of biomass and NPP estimates from vast forest areas in relation to climatic conditions. The analysis was based on biomass data in 1236 sample plots as well as both NPP and biomass estimates in 480 sample plots that were established in mixed spruce and fir stands. Data were available for the entire Eurasian territory from the UK to South China and Japan, and included information on both total biomass and various biomass components. The climatic conditions of the sampled forests were characterized by using specific indices of zonality and continentality. A system of recursive equations was fitted to the data using standard regression analysis. For both the aboveground and total NPP, we found a statistically significant increase from the North to the South, but also a decrease from both the Atlantic and Pacific coasts towards the continental center of Siberia. We also found that lower upper-story NPP is compensated by higher understory NPP and vice versa. On the other hand, inconsistencies were identified concerning the share of root biomass in relation to the continentality index.