Tree Allometrics

Equations / Stem volume

Commercial stem volume from DBH, Vochysia maxima (species-specific, Table 2)

Stem volumeVochysia maxima · VochysiaceaeBrazilnaturalRead from the original paper
Photo of Vochysia maxima
© Christoph Moning · CC BY · iNaturalist
Equation

As printed (Table 2, SSEs rows)

V. maxima vc = exp(-6.66554 + 1.90852ln(DBH)) 0.55 3.027 34.0

In this library's units, ready to compute (m³)

Stem volume = exp(-6.66554 + 1.90852 * ln(D))
D
Diameter at breast height (1.3 m), cm

Species-specific equation (V. maxima, Quaruba). vc is the commercial volume of the stem (sum of Smalian log volumes, hollows discounted), not total tree volume. No back-transformation correction factor is stated, so none is applied. n_trees is the adjustment (fitting) set; DBH range is that of the whole dataset (all species), not stated per species. Ten percent of trees were held out for validation. 8 of the 36+1 species equations in Table 2 were added (the ten most important commercial species by harvested volume plus H. petraeum); the generic FMA equation was rejected by the authors' own paired t-test.

Source
Vochysia maxima Ducke Quaruba 1,541 172
Trees measured · Table 1 (columns: adjustment, validation)
29,119 trees (50.0 cm ≤ DBH ≤ 175.0 cm) of 43 commercial species
Smallest DBH · Material and Methods, Data collection
composed the commercial volume (vc) of the stem
Output · Material and Methods, Data collection
Trees measured
1,541
DBH range
from 50 cm
R²
0.55
Method
Model 2 (Husch) fitted by least squares on ln(vc); r2 is the adjusted R² recalculated in arithmetic units; Syx = 3.027 m3 (34.0%)
Where
Tapajós National Forest, Pará (community forest management concession), eastern Brazilian Amazon
Last checked
2026-11-02
Calculate
3.154
Stem volume (m³)
Fitted DBH range02468101220406080100120DBH (cm)Stem volume (m³)Stem volume

Shaded: the DBH range the model was fitted on. Other inputs held at the values above.

Checks this equation passes

On every build, the library's form and the paper's own form (in its units) must both give these values within 1%.

InputsExpectedWe getFrom
D = 603.153.15Computed from the printed form
hand-computed from the Table 2 coefficients
D = 906.846.84Computed from the printed form
hand-computed from the Table 2 coefficients
D = 13013.813.8Computed from the printed form
hand-computed from the Table 2 coefficients

Report a problem with this equation · JSON

Related