Climatic Gradients of Biomass and Net Primary Production of Mixed Picea-Abies Forests in Eurasia

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.