Biomass functions
About biomass calculations in Heureka
In Heureka the amount of biomass is caclulated with different functions depending on tree species, tree age and tree fraction (what part of the tree).
The biomass results are reported in ton per hectar units and are listed under result category Biomass, as described here.
Functions used
Established stands, above ground
For established stands (i.e. mean height ≥ 7m) you can choose either Petersson 1999 [1] or Marklund [2]. The function is selected in control table Production Model.
One special case is foliage biomass of deciduous trees, for which Repola (2000) [3] is used, with conversion factors (see below) for other broad-leaves than birch.
Young stands, above ground
For young stands, above ground tree biomass is calculated with Claesson et al 2001 [4]
Stumps and roots ≥ 2 mm
Biomass in stumps and and roots are calculated with Petersson & Ståhl (2006)[5]. These functions include roots with a diameter ≥ 2 mm, separated intw two groups: stump and roots ≥ 5 mm and roots 2 - 4.9 mm. Today there are no specific functions available to calculate biomass for stumps and roots in young stands, but starting from Heureka version 2.4 Petersson & Ståhl (2006) is used also in young stands.
Functions used when selecting Petersson for above-ground biomass in established stands
In Petersson (1999) there are several alternative function for each species and tree fraction. The functions used in Heureka are listed in the table below.
| Tree fraction | Species | ||
| Pine | Spruce | Birch | |
| Trunc excluding bark, excluding stump | T10 minus Bark | G1 minus Bark | B18 minus Bark |
| Living branches | T13 minus Foliage | G4 minus Foliage | B20 minus Foliage |
| Dead branches | T14 | G5 | B21 |
| Bark | T11 | G2 | B19 |
| Foliage | T12 | G3 | Repola 2008 |
Functions used when selecting Marklund for above-ground biomass in established stands
In Marklund (1988) there are several alternative function for each species and tree fraction. The functions used in Heureka are listed in the table below.
| Tree fraction | Species | ||
| Pine | Spruce | Birch | |
| Trunc excluding bark, excluding stump | T-6 | G-5 | B5 |
| Living branches | T-14 minus T-19 | G-12 minus G-17 | B13 |
| Dead branches | T-22 | G-20 | B-17 |
| Bark (version < 2.5) | T-2 minus T-6 | G-2 minus G-5 | B-8 |
| Bark (version ≥ 2.5) | T-10 | G-9 | B-8 |
| Foliage | T-19 | G-17 | Repola 2008 |
Adjustment for other species than pine, spruce or birch
The functions desribed above are available for pine, spruce and birch. For other broad-leaves than birch, the birch functions are used but then calibrated using conversion factors between the subject tree species "normal" wood density and the wood density for birch according to http://sv.wikipedia.org/wiki/Trädslag. For larch and lodgepole pine, the functions for pine are used, and then adjusted with the corresponding conversion factors.
References
- ↑ Petersson, Hans (1999). Biomassafunktioner för trädfaktorer av tall, gran och björk i Sverige. Umeå: Fakulteten för skogsvetenskap > Institutionen för skoglig resurshushållning, Sveriges lantbruksuniversitet. Arbetsrapport / Sveriges lantbruksuniversitet, Institutionen för skoglig resurshushållning och geomatik ; 59
- ↑ Marklund, Lars Gunnar (1988). Biomass functions pine, spruce and birch in Sweden. Report 45. Department of Forest Survey. Swedish University of Agricultural Sciences. ISBN 91-576-3524-2
- ↑ Repola, Joakko (2008). Biomass equations for birch in Finland. Silva Fennica 42(4): 605-624.
- ↑ Claesson, S., Sahlén, K. & Lundmark, T. 2001. Functions for biomass estimation of young Pinus sylvestris , Picea abies and Betula spp. from stands in northern Sweden with high stand densities. Scandinavian Journal of Forest Research 16: 138-146.
- ↑ Petersson, H. & Ståhl, G. 2006. Functions for below-ground biomass of Pinus sylvestris, Picea abies, Betula pendula and Betula pubescens in Sweden. Scandinavian Journal of Forest Research 21(Suppl 7): 84-93.