Latest Blog Posts from Bioenergy

Forest biomass estimation for North-Western Europe (BioenNW regions)

Forest biomass estimation for North-Western Europe (BioenNW regions)

BioenNW partner KIT-ITAS has developed a GIS (Geographic Information System) based model to estimate and calculate present and future biomass potentials in specific geographical regions. Thereby, all relevant biomass residues and wastes from agriculture (e.g. grass cuttings, straw), forestry, and urban areas are analysed. For the assessment of residues from forestry for our BioenNW regions, the model applies the following data sources:

  • Forest inventory data: The National forest inventory (NFI) database with detailed forest information on tree species, tree height (TH), diameter at breast height (DBH), stand and tree volume as well as protection status and occurrence of deadwood. The data is collected in a European-wide plot-network (Level II see Figure 1).
  • Digital forest maps: These maps cover forest districts, plot locations, infrastructure such as roads and property boundaries.
  • Soil data index: Datafile with soil information, soil group (SO Level I-ICP-Forest)
  • Digital elevation model: The model is a 3D raster dataset with elevations captured at 1 arc second postings (2.78E-4 degrees) or about every 30 meter (Corine Land cover).

For each modeling step an optimised GIS-based forest growth simulation program is used with harvesting and logistic modules. Depending on data availability, forest maps, timber assortments and geographic location (wood transport logistics), the theoretical and sustainably feasible above-ground forest biomass potentials can be analysed.

To calculate the above-ground biomass for each of the species (broadleaved and coniferous) reported in the NFI database, different allometric models and expansion factors are used. Furthermore all models applied diameter at breast height (DBH) and tree height (TH) to estimate the total biomass of individual trees. The biomass potentials are calculated for a spatial resolution of 1 km and 10 km grid cells, respectively.

Figure 2 shows exemplary results from the second NFI (2002). In Germany, the total forest above-ground biomass of forest trees (only trees including rejuvenation from 20 cm height) add up to nearly two billion tons (ca. 134 t/ha forest). In the state of North Rhine-Westphalia 159 million tons and in the state of Rhineland-Palatinate 151 million tons and in the state of Saarland 168 million tons are available for an energetic use. In Germany, for the period of 2002–2014, an increment of the above-ground biomass potentials is expected. This expectation can be demonstrated with the results of the third German national forest inventory (NFI³).

The above-ground biomass for the other BioenNW-regions is in general lower when compared to the forests in Germany: In the Netherlands 107 t/ha forest are calculated, in France the result is 92 t/ha forest, Belgium and Luxembourg account for 101 t/ha forest, and the United Kingdom features 76 t/ha forest (FAO 2003; ICP- Level II Plot). The differences between the calculated potentials arise from different forest sizes and management plans, forest types and types of use of forest areas.

The application of an optimized GIS-model shows new possibilities for the estimation of biomass in forests and will play a major role in the assessment of energy wood potentials in forests. A more specific assessment of feasible above-ground forest biomass potentials will be provided in the next months for all BioenNW regions.

Words by Dr. Ahssem Almehasneh,
Faculty of Environment and Natural Resources Chair of Forestry Economics and Forest Planning, Freiburg, Germany,
Institute for Technology Assessment and Systems Analysis,
Karlsruhe Institute of Technology,
Karlsruhe, Germany