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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: During the last three decades, oil crises, agricultural surpluses and global climate change enhanced the interest in short-rotation forestry (SRF). In this study, the biomass production of birch (Betula pendula Roth), maple (Acer pseudoplatanus L.—Tintigny), poplar (Populus trichocarpa ×deltoides—Hoogvorst) and willow (Salix viminalis—Orm) growing under a short-rotation (SR) management system were compared after a 4 years period. The plantation was established on former agricultural land. The sandy soil had a mean pH of 4.5 and a mean carbon content of 1.0%. Survival rates after 4 years were 75.8%, 96.8%, 86.3% and 97.6% for birch, maple, poplar and willow, respectively. The mean actual annual biomass production for these four species amounted to 2.6, 1.2, 3.5 and 3.4tDMha−1 yr−1, respectively. The large variation in biomass production at the different plots of the plantation could not be explained by the measured soil parameters. Biomass production results found here were in the lower range of values reported in literature. However, in contrast to most other studies, no weed control, fertilisation or irrigation was applied in this experiment. As marginal agricultural soils are suboptimal for the growth of poplar and willow, birch can be considered as a very interesting alternative for the establishment of SR plantations in Flanders. [Copyright &y& Elsevier]

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]