Variation in carbon content among the major tree species in hemiboreal forests in latvia

Abstract

This study was designed to estimate the variation in non‐volatile carbon (C) content in different above‐ and belowground tree parts (stem, living branches, dead branches, stumps, coarse roots and small roots) and to develop country‐specific weighted mean C content values for the major tree species in hemiboreal forests in Latvia: Norway spruce (Picea abies (L.) H. Karst.), Scots pine (Pinus sylvestris L.), birch spp. (Betula spp.) and European aspen (Populus tremula L.). In total, 372 sample trees from 124 forest stands were selected and destructively sampled. As the tree samples were pre‐treated by oven‐drying before elemental analysis, the results of this study represent the non‐volatile C fraction. Our findings indicate a significant variation in C content among the tree parts and studied species with a range of 504.6 ± 3.4 g∙kg−1 (European aspen, coarse roots) to 550.6 ± 2.4 g∙kg−1 (Scots pine, dead branches). The weighted mean C content values for whole trees ranged from 509.0 ± 1.6 g∙kg−1 for European aspen to 533.2 ± 1.6 g∙kg−1 for Scots pine. Only in Norway spruce was the whole tree C content significantly influenced by tree age and size. Our analysis revealed that the use of the Intergovernmental Panel on Climate Change (IPCC) default C content values recommended for temperate and boreal ecological zones leads to a 5.1% underestimation of C stock in living tree biomass in Latvia’s forests. Thus, the country‐specific weighted mean C content values for major tree species we provide may improve the accuracy of National Greenhouse Gas Inventory estimates.