The results of the third National Forest Inventory indicate that shrub forest accounts for 5% of the total forest area in Switzerland. It grows almost exclusively in the subalpine zone and is dominated by the woody species Alnus viridis and Pinus mugo prostrata. As a consequence of global warming and the increasing demand for sustainable energy, there is a national and international interest to quantify wood volume and biomass in shrub forests. Therefore representative coppice shoots were measured in detail to establish allometric volume and biomass functions for Alnus viridis, Pinus mugo prostrata and Salix sp. For each coppice shoot the wood volume, the wet weight, the dry weight and the carbon mass was determined as a function of the base diameter. In the next step all coppice shoots of 49 sample plot areas were measured. A regression analysis shows the relationship between the degree of cover and wood volume, and hence the biomass, in a shrub forest stand. Shrub forest stands which consist of Alnus viridis and which have a degree of cover of 100% contain on average 74 m3/ha of above-ground wood volume. More than twice of that volume, namely 166 m3/ha, is contained in corresponding Pinus mugo prostrata shrub forest stands. In Swiss shrub forests, the average aboveground wood volume amounts to 66 m3/ha, corresponding to around 2 million tons of biomass. Based on the presented volume functions it will be possible to estimate the aboveground wood volume and biomass of shrub forest stands dominated by Alnus viridis and Pinus mugo prostrata with good results. Input variable is the degree of cover of the present woody species, which can be determined efficiently on aerial photography by image interpretation.

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