Calculation guide
Tree carbon assessment with Chave 2014: data, calculation, and review
A carbon result is only as defensible as the field measurements, species match, density source, equation, and review trail behind it.
Measurements used by the calculation
The surveyor records girth in centimetres and total height in metres. Enotree derives diameter at breast height as DBH = girth / pi. The reviewed tree species must match an approved Enotree species record containing an exact species wood density in grams per cubic centimetre.
If the submitted species name cannot be matched or the density is missing, Enotree does not invent a density. The record is marked for administrator review and cannot produce a traceable final estimate until the match is resolved.
Chave 2014 above-ground biomass flow
- AGB (kg) = 0.0673 x (wood density x DBH squared x height)^0.976.
- Carbon (kg) = AGB x 0.47.
- CO2 equivalent (kg) = Carbon x 44 / 12.
- CO2 equivalent (tonnes) = CO2 equivalent kg / 1,000.
- For the current Enotree method, below-ground biomass is kept at zero and total biomass equals above-ground biomass.
Why exact species review matters
An AI suggestion or a local name is useful field evidence, but it may not be the accepted scientific name used by the density database. An administrator compares the submitted name and photographs with the Enotree database and selects the appropriate approved species record.
A project-specific assignment can resolve how that workspace interprets a submitted alias without changing the master density for every Enotree customer. This preserves one approved density per master species while allowing project administrators to correct their own records.
Interpret estimates responsibly
The Chave equation is an allometric model, not a direct weighing of the tree. Measurement error, tree form, site conditions, identification uncertainty, and model calibration range affect the result. Trees with DBH below 5 cm can still be calculated in Enotree but receive a warning that they fall below the Chave calibration range.
Use Enotree values for preliminary consultancy analysis, inventory comparison, and transparent review. Certified carbon credits, regulatory submissions, and financial claims require the methods, boundaries, uncertainty, additionality, permanence, and verification demanded by the applicable programme and independent experts.
Frequently asked questions
Does Enotree use a default wood density?
No. The current calculation requires the exact density from the approved species record. Missing or unmatched species are sent for review.
Is girth the same as DBH?
No. Girth is the circumference. Enotree derives diameter by dividing girth in centimetres by pi.
Are Enotree CO2 values certified carbon credits?
No. They are traceable model estimates. Credit issuance requires a suitable standard, project methodology, validation, and independent verification.