Description of a new procedure to estimate the carbon stocks of all forest pools and impact assessment of methodological choices on the estimates

Abstract

Forest ecosystems play a major role in atmospheric carbon sequestration and emission. Comparable organic carbon stock estimates at temporal and spatial scales for all forest pools are needed for scientific investigations and political purposes. Therefore, we developed a new carbon stock (CS) estimation procedure that combines forest inventory and soil and litter geodatabases at a regional scale (southern Belgium). This procedure can be implemented in other regions and countries on condition that available external carbon soil and litter data can be linked to forest inventory plots. The presented procedure includes a specific CS estimation method for each of the following forest pools and subpools (in brackets): living biomass (aboveground and belowground), deadwood (dead trees and snags, coarse woody debris and stumps), litter, and soil. The total CS of the forest was estimated at 86 Tg (185 Mg ha -1 ). Soil up to 0.2 m depth, living biomass, litter, and deadwood CSs account, respectively, for 48, 47, 4, and 1 % of the total CS. The analysis of the CS variation within the pools across ecoregions and forest types revealed in particular that: (1) the living biomass CS of broadleaved forests exceeds that of coniferous forests, (2) the soil and litter CSs of coniferous forest exceed those of broadleaved forests, and (3) beech stands come at the top in carbon stocking capacity. Because our estimates differ sometimes significantly from the previous studies, we compared different methods and their impacts on the estimates. We demonstrated that estimates may vary highly, from -16 to ?12 %, depending on the selected methods. Methodological choices are thus essential especially for estimating CO 2 fluxes by the stock change approach. The sources of error and the accuracy of the estimates were discussed extensively.

Carbon concentration declines with decay class in tropical forest woody debris

“…As for the carbon concentration, many studies have for convenience used a fixed value (e.g. 50%) of mass as carbon in both biomass and necromass (Brienen et al, 2015;Chao et al, 2009;Coomes et al, 2002;Latte et al, 2013). We found that carbon concentration decreased markedly with decay classes (Table 2; Fig.…”

“…Converting volume to carbon requires knowing both wood density and carbon concentration (IPCC, 2006;Latte et al, 2013;Weggler et al, 2012). Our study found that both wood density and carbon concentration decline significantly with the class of decay (Fig.…”

“…Chao et al, 2009;Coomes et al, 2002), or for both living and dead mass (e.g. Latte et al, 2013;Rice et al, 2004).…”

Increased tree-growth synchronization of beech (Fagus sylvatica L.) in response to climate change in northwestern Europe

“…Thus, to disentangle the specific 52 warming effect of water availability on beech, it seems more appropriate to sample trees from 53 stands with optimal growing conditions. Changes in temperature thresholds in these stands 54 might play a major role in influencing carbon stock (Latte et al, 2013) Since the 1990s, anomalies in beech health (e.g., worsening crown conditions) have been 58 observed throughout Europe (UNECE, 2005) and in Belgium (Laurent and Lecomte, 2007). 59…”

Biomass dynamics in a logged forest: the role of wood density

“…(2) and (3) to determine the AGB and RB of saplings (1 cm ≤ DBH < 10 cm) and dead standing trees. To correct for the fact that part of the mass in dead trees is already decomposed, we used a correction factor based on visual assessment of decomposition state: 1 for dead trees with no signs of decomposition, 0.75 for moderately decomposed trees and 0.5 for highly decomposed trees (Latte et al 2013). …”