# Canadian national equation, alpine fir, dbh only (stem wood plus stem bark; Table 3)

Stem biomass equation for Abies lasiocarpa, Canada, from Lambert et al. 2005. 60 trees, DBH 2.1–36.5 cm. Listed on Tree Allometrics, a free library of tree allometric equations, each quoted from the source that published it.

## Equation

As printed in Lambert et al. 2005 (Eq. 2):

> y wood = β wood1D βwood2 + ewood

Cite: https://treeallometry.org/equations/lambert-2005-alpine-fir-stem/#equation

In this library's units, ready to compute (stem biomass in kg):

```
Stem biomass = 0.0528 * D^2.4309 + 0.0108 * D^2.3876
```

Inputs: D = Diameter at breast height (1.3 m) (cm).
The source's own form: 0.0528 * dbh^2.4309 + 0.0108 * dbh^2.3876, with dbh in cm; output in kg.
Cite: https://treeallometry.org/equations/lambert-2005-alpine-fir-stem/#canonical

## What it covers

- Output: Stem biomass, kg
- Taxon: Abies lasiocarpa (species), family Pinaceae; conifer
- Where: Alberta, Canada (ENFOR archival data, early 1980s). Cite: https://treeallometry.org/equations/lambert-2005-alpine-fir-stem/#where
- Biomes: boreal
- Stand: not stated
- Trees measured: 60. Cite: https://treeallometry.org/equations/lambert-2005-alpine-fir-stem/#n_trees
- DBH range: 2.1–36.5 cm. Cite: https://treeallometry.org/equations/lambert-2005-alpine-fir-stem/#dbh
- R²: 0.97. Cite: https://treeallometry.org/equations/lambert-2005-alpine-fir-stem/#r2
- Method: Nonlinear seemingly unrelated regression with weight functions; additivity constrained so compartments sum to total. Cite: https://treeallometry.org/equations/lambert-2005-alpine-fir-stem/#method
- Verification: read in the original source
- Last checked: 2026-11-03. Cite: https://treeallometry.org/equations/lambert-2005-alpine-fir-stem/#checked_at

A missing fit statistic is one the source doesn't state, or that we haven't recorded; it is never estimated. Outside the stated DBH range or region, the equation is an extrapolation.

## Source

Lambert, M.-C., Ung, C.-H., Raulier, F. (2005). Canadian national tree aboveground biomass equations. Canadian Journal of Forest Research, 35(8), 1996–2018.

- DOI: https://doi.org/10.1139/x05-112
- Access: paywalled
- Copy we read: https://www.esf.edu/quest/documents/Lambertetal.2005.Canadatreebiomass.pdf
- Every equation from this source: https://treeallometry.org/sources/lambert-2005/
- Cite: https://treeallometry.org/equations/lambert-2005-alpine-fir-stem/#source

## The facts, in the source's words

**Equation** (Eq. 2):

> y wood = β wood1D βwood2 + ewood

Cite: https://treeallometry.org/equations/lambert-2005-alpine-fir-stem/#equation

**Equation** (Eq. 2):

> y bark = β bark1D βbark2 + e bark

Cite: https://treeallometry.org/equations/lambert-2005-alpine-fir-stem/#quote-expression

**Equation** (Table 3, Alpine fir):

> Alpine fir bwood1 0.0528

Cite: https://treeallometry.org/equations/lambert-2005-alpine-fir-stem/#quote-expression-2

**Equation** (Table 3, Alpine fir):

> bwood2 2.4309

Cite: https://treeallometry.org/equations/lambert-2005-alpine-fir-stem/#quote-expression-3

**Equation** (Table 3, Alpine fir):

> bbark1 0.0108

Cite: https://treeallometry.org/equations/lambert-2005-alpine-fir-stem/#quote-expression-4

**Equation** (Table 3, Alpine fir):

> bbark2 2.3876

Cite: https://treeallometry.org/equations/lambert-2005-alpine-fir-stem/#quote-expression-5

**Trees measured** (Table 2 (No. of trees)):

> Alpine fir               60     19.6±1.3     14.8±0.8      158.4±19.5

Cite: https://treeallometry.org/equations/lambert-2005-alpine-fir-stem/#quote-fit-n-trees

**Smallest DBH** (Table 2, Alpine fir (ranges of dbh, height, total biomass)):

> (2.1;36.5)   (2.2;23.7)     (1.7;461.8)

Cite: https://treeallometry.org/equations/lambert-2005-alpine-fir-stem/#quote-fit-dbh-min-cm

**R²** (Table 5, Alpine fir (AdjRSq in the dbh-based set, first block)):

> Stem 0.0595 0.97 20.7 2.67 0.0007 0.99 11.7 3.87

Cite: https://treeallometry.org/equations/lambert-2005-alpine-fir-stem/#quote-fit-r2

**Our note:** Stem from ground level to tree top, stem wood plus stem bark; the stem is the sum of the two compartment equations. r2 is the adjusted R² (AdjRSq) of this compartment in Table 5. Fitted on the original scale (weighted nonlinear seemingly unrelated regression), so there is no back-transform correction. Dead branches, cones and fruits are not part of aboveground biomass in this work (Materials). Stand type was not always recorded. Ung, Bernier & Guo (2008) later revised parameters for some species with British Columbia data; not used here.

## Checks this equation passes

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

| Inputs | Expected | We get | From |
| --- | --- | --- | --- |
| D = 20 | 90.6 | 90.6 | Computed from the printed form: computed from the published form at dbh = 20 cm |

Cite: https://treeallometry.org/equations/lambert-2005-alpine-fir-stem/#checks

The calculator on the page shows carbon as biomass × 0.47 (IPCC 2006 Guidelines, Vol. 4, Ch. 4, Table 4.3) and CO₂e as carbon × 44/12.

## How to cite

Cite the source for the equation: Lambert, M.-C., Ung, C.-H., Raulier, F. (2005). Canadian national tree aboveground biomass equations. Canadian Journal of Forest Research, 35(8), 1996–2018. https://doi.org/10.1139/x05-112

Cite this page for the record and checks: Tree Allometrics (Restoration Scope), "Canadian national equation, alpine fir, dbh only (stem wood plus stem bark; Table 3)", checked 2026-11-03, https://treeallometry.org/equations/lambert-2005-alpine-fir-stem/. Data CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Quotes are the authors' words.

Data for this equation: https://treeallometry.org/data/equations/lambert-2005-alpine-fir-stem.json
Report a problem: email info@restorationscope.com with the equation id (lambert-2005-alpine-fir-stem) and where the right value appears.