Evaluated procedures to be applied in national carbon stock and stock change of trees in some European countries (original) (raw)
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Growing stock-based assessment of the carbon stock in the Belgian forest biomass
Annals of Forest Science, 2005
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.
Analysing different carbon estimation methods for Austrian forests
Austrian Journal of Forest Science
Terrestrial tree measurements of diameter at breast height (DBH) and height are used to estimate the carbon of different tree compartments. In this paper we present four different carbon estimation methods for three major tree species (Norway spruce, common beech and Scots pine) in Austria and demonstrate the differences in the resulting predictions according to the chosen method. Carbon estimations of single trees can be generally based on biomass equations or biomass expansion factors. The investigated methods comprise the Austrian biomass functions (ABF), biomass functions based on allometric relationships of tree data according to Burger (Burger), biomass expansion factors (BEF) and calculations recommended by the Intergovernmental Panel on Climate Change (IPCC). Since we are interested in the theoretical impacts of the chosen method we generated a standardized data set representing a similar number of trees within each diameter class. We calculate the overall aboveground carbon...
Inventory-based carbon stock of Flemish forests: a comparison of European biomass expansion factors
Annals of Forest Science, 2004
Different European Biomass Expansion Factors (BEFs) were compared for the inventory-based quantification of total aboveground and belowground biomass in forests. Therefore a qualitative analysis is performed on the biomass results obtained through the BEF approach and those from experimentally established allometric relations based on destructively sampled and fully excavated trees. Total organic carbon (OC) stock in aboveground and belowground living biomass of Flemish forests amounts to 12 Mt on average, with a significantly larger OC stock per hectare in deciduous forests compared to coniferous or mixed forest types. Total forest biomass seems to be fairly well approximated by a multiplication of the standing stock with either one of the applied BEFs. However an indication of the volume and age class for which the BEFs are established and a refined diameter-volume-biomass relation for oak trees in Europe, are required to gain more accurate results. forest inventory / carbon stock / biomass expansion factor / allometric relation Résumé-Stocks de carbone dans la biomasse des forêts en Flandre à partir d'un inventaire permanent des ressources forestières : une comparaison des facteurs européens d'expansion. Différents facteurs européens d'expansion pour la biomasse (FEB) sont utilisés pour la quantification de la biomasse aérienne et souterraine des écosystèmes forestiers à partir d'un inventaire permanent. Une analyse comparative des résultats obtenus, d'une part, par l'approche des FEB et d'autre part, par l'utilisation de relations expérimentales à l'aide d'un échantillon d'arbres complètement découpés et déterrés est effectuée. Dans les forêts en Flandre le stock de carbone dans la biomasse aérienne et souterraine est estimé à 12 Mt en moyenne ; le stock de carbone des forêts d'essences feuillues est significativement plus élevé que celui des bois de conifères ou des forêts mixtes. La biomasse des forêts est relativement bien évaluée par la multiplication du volume à l'hectare sur écorce par l'un des FEB européens. Néanmoins les valeurs des FEB dépendent de l'âge et du volume des peuplements qui ont permis de les évaluer. L'utilisation des relations circonférence-volume-biomasse affinées pour le chêne en Europe semble indispensable pour obtenir des résultats plus précis. inventaire des ressources forestières / stock de carbone / facteur d'expansion / relation allométrique
Forest Ecology and Management, 2006
Growing stocks of trees in Europe have increased in a magnitude that is significant in terms of carbon (C) sink strength. Estimates of the soil C sink strength that this increased stock of trees may have induced on a regional scale are scarce, uncertain and difficult to compare. This illustrates the need for a widely applicable calculation method. Here, we calculate a C budget of productive forest in southeast Norway based on forest inventory information, biomass expansion factors (BEF), biomass turnover rates and the dynamic soil model Yasso. We estimate a 29% increase (112-145 Tg) of C in biomass between 1971 and 2000, and estimate the associated increase of C in soils (including dead wood) to be 4.5% (181-189 Tg). The C sink strengths in biomass and soils (including dead wood) in 1990 are 0.38 and 0.08 Mg ha À1 yr À1 , respectively. Estimated soil C density is 58 Mg C ha À1 or ca 40% of measured soil C density in Norwegian forest soils. A sensitivity analysis -using uncertainty estimates of model inputs and parameters based on empirical data -shows that the underestimation of the soil C stock can be due to overestimation of decomposition rates of recalcitrant organic matter in the soil model and to including only trees as a source of litter. However, uncertainty in these two factors is shown to have a minimal effect on soil sink estimates. The key uncertainty in the soil sink is the initial value of the soil C stock, i.e. the assumed steady state soil C stock at the start of the time series in 1970. However, this source of uncertainty is reduced in importance for when approaching the end of the data series. This indicates that a longer time series of forest inventory data will decrease the uncertainty in the soil sink estimate due to initialisation of the soil C stock. Other, less significant, sources of uncertainty in estimates of soil stock and sink are BEF for fine roots and turnover rates of fine roots and foliage. The used method for calculation of a forest C budget can be readily applied to other regions for which similar forest resource data are available. #
Forest Systems, 2012
To estimate forest carbon pools from forest inventories it is necessary to have biomass models or biomass expansion factors. In this study, tree biomass models were developed for the main hardwood forest species in Spain: Alnus glutinosa, Castanea sativa, Ceratonia siliqua, Eucalyptus globulus, Fagus sylvatica, Fraxinus angustifolia, Olea europaea var. sylvestris, Populus x euramericana, Quercus canariensis, Quercus faginea, Quercus ilex, Quercus pyrenaica and Quercus suber. Different tree biomass components were considered: stem with bark, branches of different sizes, above and belowground biomass. For each species, a system of equations was fitted using seemingly unrelated regression, fulfilling the additivity property between biomass components. Diameter and total height were explored as independent variables. All models included tree diameter whereas for the majority of species, total height was only considered in the stem biomass models and in some of the branch models. The comparison of the new biomass models with previous models fitted separately for each tree component indicated an improvement in the accuracy of the models. A mean reduction of 20% in the root mean square error and a mean increase in the model efficiency of 7% in comparison with recently published models. So, the fitted models allow estimating more accurately the biomass stock in hardwood species from the Spanish National Forest Inventory data.
Indirect methods of large-scale forest biomass estimation
European Journal of Forest Research, 2007
Forest biomass and its change over time have been measured at both local and large scales, an example for the latter being forest greenhouse gas inventories. Currently used methodologies to obtain stock change estimates for large forest areas are mostly based on forest inventory information as well as various factors, referred to as biomass factors, or biomass equations, which transform diameter, height or volume data into biomass estimates. However, while forest inventories usually apply statistically sound sampling and can provide representative estimates for large forest areas, the biomass factors or equations used are, in most cases, not representative, because they are based on local studies. Moreover, their application is controversial due to the inconsistent or inappropriate use of definitions involved. There is no standardized terminology of the various factors, and the use of terms and definitions is often confusing. The present contribution aims at systematically summarizing the main types of biomass factors (BF) and biomass equations (BE) and providing guidance on how to proceed when selecting, developing and applying proper factors or equations to be used in forest biomass estimation. The contribution builds on the guidance given by the IPCC (Good practice guidance for land use, land-use change and forestry, 2003) and suggests that proper application and reporting of biomass factors and equations and transparent and consistent reporting of forest carbon inventories are needed in both scientific literature and the greenhouse gas inventory reports of countries.