Carbon concentration variability of 10 Chinese temperate tree species

A mass-based carbon (C) concentration ([C]) of 50% in dry wood is widely accepted as a constant factor for conversion of biomass to C stock. However, the [C] varies with tree species, and few data on [C] are available for the Chinese temperate tree species. In this study, we examined inter- and intra-specific variations of [C] in biomass tissues for 10 co-occurring temperate tree species in northeastern China. The species were Korean pine (Pinus koraiensis Sieb. et Zucc.), Dahurian larch (Larix gmelinii Rupr.), Mongolian oak (Quercus mongolica Fisch.), white birch (Betula platyphylla Suk.), Amur cork-tree (Phellodendron amurense Rupr.), Manchurian walnut (Juglans mandshurica Maxim.), Manchurian ash (Fraxinus mandshurica Rupr.), aspen (Populous davidiana Dode), Mono maple (Acer mono Maxim.), and Amur linden (Tilia amurensis Rupr.). The mean tissue [C] across the species varied from 47.1% in fine root to 51.4% in foliage. The mean stem [C] of the 10 species was 49.9 ± 1.3% (mean ± SE). The weighted mean C concentration (WMCC) for the species ranked as: Amur cork-tree (55.1%) > Amur linden (53.9%) > Korean pine (53.2%) > Manchurian ash (52.9%) > Manchurian walnut (52.4%) > Mongolian oak (47.6%) > Dahurian larch (46.9%) > Mono maple (46.4%) > white birch (46.1%) > aspen (43.7%). The WMCC of the dominant trees was negatively correlated to mean annual increment of biomass (MAI), suggesting that planting fast-growing tree species for C sequestration in afforestation and reforestation practices sacrifice some C gain from increasing MAI due to decreasing [C]. Failing to account for the inter- and intra-specific variations in [C] will introduce a relative error of −6.7% to +7.2% in estimates of biomass C stock from inventory data, of which >93% is attributed to ignoring the inter-specific variation in [C].