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Abstract: Belgium, being an EU country, has committed itself to a 7.5% reduction of greenhouse gas emissions during the first commitment period of the Kyoto Protocol. Within this framework, the Flemish government aims at reaching a share of 6% of renewable electricity in the total electricity production by 2010. In this work, the biomass production of birch, maple, poplar and willow in a short-rotation forestry (SRF) plantation after a 4-year growth period served as the base to calculate the amount of (electrical) energy that could be produced by this type of bioenergy crop in Flanders. The maximum amount of electricity that could be provided by SRF biomass was estimated at 72.9GWhe year−1, which only accounts for 0.16% of the total electricity production in this region. Although the energy output was rather low, the bioenergy production process under consideration appeared to be more energy efficient than energy production processes based on fossil fuels. The high efficiency of birch compared to the other species was mainly due to the high calorific value of the birch wood. The maximum CO2 emission reduction potential of SRF plantations in Flanders was estimated at only 0.09% of the total annual CO2 emission. The most interesting application of SRF in Flanders seemed to be the establishment of small-scale plantations, linked to a local combined heat and power plant. These plantations could be established on marginal arable soils or on polluted sites, and they could be of importance in the densely populated area of Flanders because of other environmental benefits, among which their function as (temporary) habitat for many species. [Copyright &y& Elsevier]

Abstract Evaluations of soil organic carbon (SOC) stocks are often based on assigning a carbon density to each one of a number of ecosystems or soil classes considered, using data from soil profiles within these categories. A better approach, in which the use of classification methods by which extrapolation of SOC data to larger areas is avoided, can only be used if enough data are available at a sufficiently small scale. Over 190 000 SOC measurements (0–24 cm) have been made in the Flemish cropland (the Northern part of Belgium) in the 1989–2000 period. These SOC data were grouped into 3-year periods and as means plus standard deviation per (part of) community (polygons). This large dataset was used to calculate SOC stocks and their evolution with time, without data extrapolation. Using a detailed soil map, larger spatial groups of polygons were created based on soil texture and spatial location. Linear regression analysis showed that in the entire study area, SOC stocks had decreased or at best had remained stable. In total, a yearly decrease of 354 kton OC yr-1 was calculated, which corresponds with a net CO2 emission of 1238 kton CO2 yr-1 . Specific regions with a high carbon sequestration potential were identified, based on SOC losses during the 1989–2000 period and the mean 1999 SOC content, compared to the average SOC content of soils in Flanders with a similar soil texture. When restoring the SOC stocks to their 1990 level, we estimated the carbon sequestration potential of the Flemish cropland soils to be some 300 kton CO2 yr-1 at best, which corresponds to a 40-year restoration period. In conclusion, we can say that in regions where agricultural production is very intense, carbon sequestration in the cropland may make only a very modest contribution to a country's effort to reduce greenhouse gas emissions. [ABSTRACT FROM AUTHOR]

This paper tests different methods to assess the species richness of vascular plants in fragmented forests embedded in agricultural landscapes. Certain plant species enabled us to rank forest patches in order of actual species richness, but failed to predict the exact number of plant species. However, the exact species richness could be satisfactorily predicted through multiple linear regression models that used a series of environmental variables (69% explained variance). Using this method, species richness was easier to predict in forests on alluvial soil and of young age (77 and 66% explained variance, respectively) than in those on non-alluvial soil and of old age (47 and 50% explained variance, respectively). The latter needed more observations (improvement to 70 and 56% explained variance, respectively) or more variables (improvement to 61 and 73% explained variance, respectively) to develop a reliable model. Predictions based on data obtained using GIS were satisfactory only for forests on alluvial soil (58% explained variance). Important indicators of species-rich forests were habitat diversity, forest age and forest area. Species richness was substantially larger in forests on alluvial soil compared with those on non-alluvial soil. Lower phosphorus availability to plants and proximity to older forests indicated a higher species richness in forests on alluvial soil and of young age. A higher pH and a lower C/N-ratio of soil indicated a higher species richness in forests on non-alluvial soil and of old age. It is thus possible to predict species richness of vascular plants in different types of forest using environmental variables, which is useful when selecting and managing forests for biodiversity conservation and restoration. [Copyright &y& Elsevier]