# How do agroforestry credits turn tree measurements into tonnes of carbon?

Canonical: https://senseible.earth/answers/agroforestry-credits-tree-biomass-equations-order

Through allometric equations that link a simple measurement, such as trunk diameter, to biomass. Isometric's protocol allows only published equations, chosen in order: local peer-reviewed ones, then Chave et al. 2014 for the tropics, then national forest inventories, then IPCC generalised equations. A global default carbon fraction is a last resort.

## The order of equations

Equations vary by species, age and site, and not every species has a well-established one. The protocol restricts the choice to those published in reputable literature.

1. Local peer-reviewed equations.
2. Chave et al. (2014) for tropical regions.
3. National forest inventories.
4. IPCC generalised equations.

## The carbon fraction of dry biomass

The methodology permits a conservative global default only when more specific factors are unavailable. Preferred are regional or species-specific values, or genus-specific or national average values, supported by scientific literature. ICVCM notes the default is an average, specific data is mandatory where it exists, and verifiers and the program oversee this.

## What it means in the field

- Record species, planting date and trunk measurements for sampled trees.
- Ask the developer which equation it will use for each of your species and why.

## What Senseible does here

Senseible does not issue or verify carbon credits and is not a registry. It gives carbon credit eligibility signals from your own records and keeps those records in order for a verifier. Verified here means rule checks passed against the evidence, not third-party assurance.

- [Shade trees and carbon removals on tea and coffee estates](https://senseible.earth/answers/shade-trees-carbon-removals-tea-coffee-estate)
- [Coffee agroforestry carbon credits](https://senseible.earth/answers/coffee-agroforestry-carbon-credits-india)
- [Carbon credits](https://senseible.earth/carbon-credits)

Sources: [ICVCM, Observations on category assessment: afforestation, reforestation and revegetation, agroforestry (August 2026)](https://icvcm.org/wp-content/uploads/2026/08/Board-Observations_ARR_V_ISM_Agroforestry_v1.0.pdf)

Last reviewed 2026-11-04.