# Tropical pines AGB from DBH (Eq. 3.1.8 / 3.2.8)

Aboveground biomass equation for Pinus, Global, from Brown 1997. 63 trees, DBH 2–52 cm. Listed on Tree Allometrics, a free library of tree allometric equations, each quoted from the source that published it.

## Equation

As printed in Brown 1997 (Eq. 3.1.8, Section 3.2.1 table):

> Y(kg) = exp{-1.170+2.119*ln(D)}

Cite: https://treeallometry.org/equations/brown-1997-pine/#equation

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

```
Aboveground biomass = exp(-1.170 + 2.119 * ln(D))
```

Inputs: D = Diameter at breast height (1.3 m) (cm).
The source's own form: exp(-1.170 + 2.119 * ln(D)), with D in cm; output in kg.
Cite: https://treeallometry.org/equations/brown-1997-pine/#canonical

## What it covers

- Output: Aboveground biomass, kg
- Taxon: Pinus (genus), family Pinaceae; conifer
- Where: Pine stands in the southeastern USA, India and Puerto Rico; offered for tropical pine forests. Cite: https://treeallometry.org/equations/brown-1997-pine/#where
- Biomes: tropical, subtropical
- Stand: mixed
- Trees measured: 63. Cite: https://treeallometry.org/equations/brown-1997-pine/#n_trees
- DBH range: 2–52 cm. Cite: https://treeallometry.org/equations/brown-1997-pine/#dbh
- R²: 0.98. Cite: https://treeallometry.org/equations/brown-1997-pine/#r2
- Verification: read in the original source
- Last checked: 2026-11-01. Cite: https://treeallometry.org/equations/brown-1997-pine/#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

Brown, S. (1997). Estimating Biomass and Biomass Change of Tropical Forests: a Primer. FAO Forestry Paper 134. Rome: Food and Agriculture Organization of the United Nations. ISBN 92-5-103955-0.

- Link: https://www.fao.org/4/w4095e/w4095e00.htm
- Access: open access
- Copy we read: https://www.fao.org/4/w4095e/w4095e06.htm
- Every equation from this source: https://treeallometry.org/sources/brown-1997/
- Cite: https://treeallometry.org/equations/brown-1997-pine/#source

## The facts, in the source's words

**Equation** (Eq. 3.1.8, Section 3.2.1 table):

> Y(kg) = exp{-1.170+2.119*ln(D)}

Cite: https://treeallometry.org/equations/brown-1997-pine/#equation

**Units** (Section 3.2.1, biomass regression equations table header):

> Y= biomass per tree in kg, D = dbh in cm, and BA = basal area in cm2

Cite: https://treeallometry.org/equations/brown-1997-pine/#quote-published-units

**Trees measured** (Section 3.2.1, conifer forests):

> D = dbh, cm; range in dbh = 2-52 cm; number of trees =63; adjusted r 2 =0.98

Cite: https://treeallometry.org/equations/brown-1997-pine/#quote-fit-n-trees

**Our note:** Preliminary equation from harvested pines in eight literature sources (southeastern USA, India, Puerto Rico), several Pinus species pooled. The HTML labels it Eq. 3.1.8 while the text calls it Eq. 3.2.8. r2 is adjusted r². The primer does not say whether a log back-transform correction is included; none applied. Stand origin (plantation vs natural) not stated.

## 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 | 177 | 177 | Computed from the printed form: computed with python3 from the published form |

Cite: https://treeallometry.org/equations/brown-1997-pine/#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: Brown, S. (1997). Estimating Biomass and Biomass Change of Tropical Forests: a Primer. FAO Forestry Paper 134. Rome: Food and Agriculture Organization of the United Nations. ISBN 92-5-103955-0.

Cite this page for the record and checks: Tree Allometrics (Restoration Scope), "Tropical pines AGB from DBH (Eq. 3.1.8 / 3.2.8)", checked 2026-11-01, https://treeallometry.org/equations/brown-1997-pine/. 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/brown-1997-pine.json
Report a problem: email info@restorationscope.com with the equation id (brown-1997-pine) and where the right value appears.