Equations / Stem volume
Peat swamp forest, non-Dipterocarpaceae group, volume from D (model 1)
As printed (Best model, non-Dipterocarpaceae group, p. 10 (Tabel 3 model 1))
In this library's units, ready to compute (m³)
Stem volume = exp(-8.398596 + 2.4688 * ln(D))D- Diameter at breast height (1.3 m), cm
Volume to a 5 cm top diameter by Smalian's formula on 2 m sections (stem volume, no branches). Diameter was taken at 1.3 m or 20 cm above ground (as printed: 'setinggi dada (1,3 m) atau 20 cm di atas permukaan tanah'); the paper does not say which trees used which. Natural-log form as printed, with no correction factor stated. Fit ranges are those of the model-development subset (70% of the trees, Table 1). Caution: Tabel 3 prints identical coefficients for models 1, 2, 5 and 6 in both the Dipterocarpaceae and non-Dipterocarpaceae groups (with different F and Se values), which looks like a typesetting error in the paper; the text on p. 10 attributes this model 1 to the non-Dipterocarpaceae group, which is the reading used here.
doi:10.20886/jwas.v7i1.5538 · Open access · copy we read
Kelompok non-dipterocarpaceae Diameter 13,9 5,6 27,0 6,0 42
- Trees measured
- 42
- DBH range
- 5.6–27 cm
- Height range
- 6–24 m
- R²
- 0.973
- Method
- ordinary least squares on ln(V) = a0 + a1 ln(D)
- Where
- IUPHHK PT Tingang Karya Mandiri peat swamp forest, Central Kalimantan
- Last checked
- 2026-11-02
Shaded: the DBH range the model was fitted on. Other inputs held at the values above.
On every build, the library's form and the paper's own form (in its units) must both give these values within 1%.
| Inputs | Expected | We get | From |
|---|---|---|---|
| D = 8 | 0.0382 | 0.0382 | Computed from the printed form computed from the published form (coefficients as printed) |
| D = 15 | 0.180 | 0.180 | Computed from the printed form computed from the published form (coefficients as printed) |
| D = 25 | 0.636 | 0.636 | Computed from the printed form computed from the published form (coefficients as printed) |
Related
- Peat swamp forest, all species, volume from D (model 3) · same paper · Stem volume
- Peat swamp forest, Dipterocarpaceae group, volume from D and H (model 7) · same paper · Stem volume