Potentiale zur energetischen Nutzung von Biomasse in der ... - EPFL

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forest route density, all forest stands are at least within a distance of 600 m from the nearest route in
the Canton of Vaud).
Accessibility
Forest stand accessibility for motor vehicles mainly depends on slope and soil characteristics. Slopes
above 50% are considered inaccessible and require specific harvesting machinery, i.e. a cable crane or a
helicopter.
The strength and the roughness of the soil are complementary variables that play an important role in
defining whether an area is accessible by motor vehicles without any risk of ground damage and soil fertility
degradation. Data can be interpreted from the soil property map from the Swiss Agriculture Research
station in Reckenholz or from the geotechnical map from the Swiss Federal Office of Topography.
Soil characteristics were not considered in the definition of accessibility in the present study.
Distance to the road
The Vector25 transportation network layer includes several types of roads, based on the Swiss Federal
Office of Topography typology. Relevant road categories, corresponding to forest roads, trails and paths,
needed to be selected: 4th, 5th and 6th class roads were chosen for the study.
In order to take into account the distance between forest stands and the nearest route in inaccessible
areas, 100 m and 600 m buffers were computed around each road segment. Then a spatial query consisting
in determining for each pixel whether its centroid was located within a given buffer zone allowed
us to select forest stands located at a minimal distance. Up or downwards direction to the road was not
taken into account.
Farm-gate prices and total harvesting costs
The different categories of trees, their relative accessibility and eventually their distance to the nearest
route are the basic conditions that define the choice of harvesting technique and the biomass farm-gate
prices. Then, the total harvesting costs can be estimated by multiplying the potential volume of energywood
of each species type in Sm 3 by respective farm-gate price (in our case it corresponds to average
cost of harvesting), as defined by the local conditions and the considered harvesting scenario.
10.3.8 Results
The total quantities of biomass available for energy use that were obtained in the case study are as follows
(Table 56):
Public Forests Private forests Total
Deciduous Min 287’074 88’160 375’234
Max 323’702 95’948 419’650
Coniferous Min 168’600 50’301 218’901
Max 215’510 64’213 279’723
Total Min 455’674 138’461 594’135
Max 539’212 160’161 699’373
Table 56 Calculated available biomass quantities in Sm 3 in the Canton of Vaud (minimal and maximal scenarios).
The way these potential biomass volumes are spatially distributed is represented on the following map
(Figure 50).