Growing stock-based assessment of the carbon stock in the Belgian forest biomass

Abstract

-Belgian forests covered 693 181 ha in 2000, representing 22.7% of the total land area. As no biomass or carbon stock data are included in the Flemish and Walloon regional forest inventories, species-specific wood densities, biomass expansion factors s.s. and carbon content values were critically selected from the literature. Based on these conversion and expansion factors, and on data from the forest inventories, the total C-stock in the living biomass of productive Belgian forests was assessed at 60.9 Mt C in the year 2000. The overall mean C-stock amounted to 101.0 t C ha -1 . This value was in the higher range of values reported for the neighbouring countries, mainly due to a high mean growing stock in the Belgian forests (261.9 m 3 ha -1 ). The conversion from wood volume to wood biomass based on wood density values reported in the literature appeared to introduce the largest variability in the assessment of the carbon stocks. Additional measurements of wood densities in Belgian forests could help to reduce the uncertainty related to this factor. Because of the time-consuming and destructive character of the determination of biomass expansion factors s.s. (BEFs), the establishment of new BEFs does not have the highest priority in the framework of improving the assessment of the biomass carbon stock in the Belgian forests. As the median C-content value for all species except beech was equal to the default IPCC-value of 50% carbon in dry matter, it seems appropriate to use this value for future calculations.forest inventory / carbon stock / biomass expansion factor / wood density / aboveground and belowground biomass / carbon content Résumé -Estimation des stocks de carbone dans la biomasse des forêts en Belgique. La forêt belge couvrait 693 181 ha en 2000, ce qui représente 22,7 % de la surface totale du pays. Les inventaires forestiers flamands et wallons n'incluent pas de mesures directes de biomasse ou de stock de carbone. Pour calculer les stocks de carbone dans les arbres forestiers à partir des volumes de bois fort, les infradensités du bois, les facteurs d'expansion de la biomasse et les teneurs en carbone ont été sélectionnés dans la littérature. En 2000, les stocks de carbone dans la biomasse des forêts belges productives étaient de 60,9 Mt C, soit 101,0 t C ha -1 . Cette dernière valeur est relativement haute comparée avec celles observées dans les forêts des pays avoisinants, à cause d'un grand volume de bois fort dans les forêts belges (261,9 m 3 ha -1 ). L'infradensité du bois semble être le facteur qui introduit la plus importante variabilité dans le calcul des stocks de carbone dans la biomasse. Des mesures complémentaires des infradensités du bois des essences les plus communes en Belgique pourraient aider à réduire significativement les incertitudes sur les mesures des stocks de carbone dans les forêts. La détermination expérimentale des facteurs d'expansion est coûteuse en temps et se base sur des analyses destructives. Ainsi, l'obtention de facteurs d'expansion propre à la situati...

Effects of planting density on the distribution of biomass in a douglas-fir plantation in southern Italy

“…According to IPCC (2003), the uncertainty involved in using generic BEF is approximately 30%, but few authors found errors up to 70% (Ravindranath & Ostwald 2008). Because trees demonstrate different biomass allocation patterns and adaptive strategies in response to abiotic factors such as temperature, water and nutrients, BEFs are hypothesized to vary with forest types and abiotic factors, although such variation has not been well examined to date (Vande Walle et al 2005). Major changes in silvicultural practices that might lead to changes in tree allometry, affecting diameter distributions and stocking density of the stands, could also influence BEF values.…”

Incertitudes pour l’estimation des facteurs d’expansion de la biomasse chez l’épicéa en République tchèque

“…for Russia [23]. Recently, the aboveground biomass of forests in the Czech Republic was estimated with constant BEFs based either on national studies or IPCC defaults [2,7], similarly as in many other countries [14,27], although it is known that during stand development the relative proportions of canopy and stem in the total mass vary [22]. In the United Kingdom, Levy et al [13] showed that tree-level BEFs were dependent on tree height, while Fang et al [5] modelled BEFs as a function of stem volume in China.…”

Évolution des stocks de carbone dans la biomasse des forêts belges entre 1984 et 2000

“…The three resulting datasets (1984 and 2000 for Wallonia and 2000 for Flanders) were processed by Perrin et al (2000) and Vande Walle et al (2005) in order to compute total BOC stocks per sampling plot. The per-plot values were then aggregated for the year 2000 in a spatially implicit approach in order to present total BOC stocks for Belgium (Vande Walle et al, 2005).…”