# Quercus cerris AGB, Zerqan site (DBH squared and height, Table 6)

Aboveground biomass equation for Quercus cerris, Albania, from Istrefi et al. 2018. 11 trees, DBH 2.5–14 cm. Listed on Tree Allometrics, a free library of tree allometric equations, each quoted from the source that published it.

## Equation

As printed in Istrefi et al. 2018 (Table 6, Zerqan row, total aboveground dry weight):

> DW = –3.24 + 0.01 • DBH2 + 2.19 • H

Cite: https://treeallometry.org/equations/istrefi-2018-zerqan-dbh2-h/#equation

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

```
Aboveground biomass = -3.24 + 0.01 * D^2 + 2.19 * H
```

Inputs: D = Diameter at breast height (1.3 m) (cm); H = Total tree height (m).
The source's own form: -3.24 + 0.01 * DBH^2 + 2.19 * Ht, with DBH in cm, Ht in m; output in kg.
Cite: https://treeallometry.org/equations/istrefi-2018-zerqan-dbh2-h/#canonical

## What it covers

- Output: Aboveground biomass, kg
- Taxon: Quercus cerris (species), family Fagaceae; broadleaf
- Where: Zerqan, Albania (young coppice stand). Cite: https://treeallometry.org/equations/istrefi-2018-zerqan-dbh2-h/#where
- Biomes: temperate
- Stand: natural
- Trees measured: 11. Cite: https://treeallometry.org/equations/istrefi-2018-zerqan-dbh2-h/#n_trees
- DBH range: 2.5–14 cm. Cite: https://treeallometry.org/equations/istrefi-2018-zerqan-dbh2-h/#dbh
- Height range: 2.2–10.5 m. Cite: https://treeallometry.org/equations/istrefi-2018-zerqan-dbh2-h/#height
- R²: 0.96. Cite: https://treeallometry.org/equations/istrefi-2018-zerqan-dbh2-h/#r2
- Method: linear or nonlinear regression without transformation. Cite: https://treeallometry.org/equations/istrefi-2018-zerqan-dbh2-h/#method
- Verification: read in the original source
- Last checked: 2026-11-02. Cite: https://treeallometry.org/equations/istrefi-2018-zerqan-dbh2-h/#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

Istrefi, E., Toromani, E., Çollaku, N. (2018). Allometric Relationships for Estimation of Above-Ground Biomass in Young Turkey Oak (Quercus cerris L.) Stands in Albania. Acta Silvatica et Lignaria Hungarica, 14(1), 65-81.

- DOI: https://doi.org/10.2478/aslh-2018-0004
- Access: open access
- Copy we read: http://real.mtak.hu/88131/1/10.2478-aslh-2018-0004.pdf
- Every equation from this source: https://treeallometry.org/sources/istrefi-2018/
- Cite: https://treeallometry.org/equations/istrefi-2018-zerqan-dbh2-h/#source

## The facts, in the source's words

**Equation** (Table 6, Zerqan row, total aboveground dry weight):

> DW = –3.24 + 0.01 • DBH2 + 2.19 • H

Cite: https://treeallometry.org/equations/istrefi-2018-zerqan-dbh2-h/#equation

**R²** (Table 6, Zerqan row, total aboveground dry weight, R2 column):

> R2 0.96

Cite: https://treeallometry.org/equations/istrefi-2018-zerqan-dbh2-h/#quote-fit-r2

**Trees measured** (Table 3, Sampled tree number):

> Zerqan 11

Cite: https://treeallometry.org/equations/istrefi-2018-zerqan-dbh2-h/#quote-fit-n-trees

**Our note:** Young Q. cerris coppice stand at Zerqan, Albania; whole-tree dry weight DW is the sum of stem, branches and leaves (roots not studied). Site-specific equation fitted on the 8-12 sampled trees of that site; 2.5-14.0 cm DBH and 2.2-10.5 m height are the sampled-tree ranges (Table 3). Fit by regression without transformation, so no correction factor. DBH and H are both in the model; second form of the pair uses DBH squared.

## 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 = 8.25, H = 6.35 | 11.3 | 11.3 | Computed from the printed form: hand-computed from the published form at the mid-point of the sampled range |

Cite: https://treeallometry.org/equations/istrefi-2018-zerqan-dbh2-h/#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: Istrefi, E., Toromani, E., Çollaku, N. (2018). Allometric Relationships for Estimation of Above-Ground Biomass in Young Turkey Oak (Quercus cerris L.) Stands in Albania. Acta Silvatica et Lignaria Hungarica, 14(1), 65-81. https://doi.org/10.2478/aslh-2018-0004

Cite this page for the record and checks: Tree Allometrics (Restoration Scope), "Quercus cerris AGB, Zerqan site (DBH squared and height, Table 6)", checked 2026-11-02, https://treeallometry.org/equations/istrefi-2018-zerqan-dbh2-h/. 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/istrefi-2018-zerqan-dbh2-h.json
Report a problem: email info@restorationscope.com with the equation id (istrefi-2018-zerqan-dbh2-h) and where the right value appears.