NCGS-M005 — Survival-adjusted carbon stock from stem diameter (provisional)
Provisional. The item may be used under NCGS pending full approval.
- Code: NCGS-M005
- Version: NCGS-2026-09-24
- Approval status: Provisional
The carbon stock of a site’s living trees at T3 or later from each tree’s measured stem diameter: above-ground biomass by the AR-AMS0007 allometric equation, carbon by the fraction 0.47, CO2 equivalent by 44/12, summed over trees observed alive; baseline and leakage zero under the small-scale conditions AR-AMS0007 states. Provisional: it applies only under a project design that carries the crediting-period and eligible-land sections a carbon module would add (ADR-0016), which no design carries in this release.
underlying principles and assumptions
Carbon follows survival, never planting (ADR-0012); a dead tree holds no stock; the stem diameter is measured, the biomass modelled by a stated equation; the standard issues no unit and certifies no impact (ADR-0014): the stock is a figure in an approved claim, nothing more; the crediting period and eligible land are design sections, not methodology parameters.
methods and procedures
On a visit at T3 or later measure the stem diameter at breast height of every living tree above the species minimum; compute each tree’s above-ground biomass from the equation, its carbon and CO2 equivalent; sum per site; report with the census’s unobserved count. Until the carbon module lands, the methodology is declared and not applied.
data requirements and inputs
A registered design with a crediting period and an eligible-land declaration (absent in this release); conformant planting records; monitoring visit records at T3 or later whose activity applies NCGS-M005, with a stem diameter on every living tree above the species minimum.
calculation and transformation rules
For each living tree i with stem diameter dbh_i in centimetres: AGB_i = exp(-1.996 + 2.32 × ln(dbh_i)) kilograms; C_i = 0.47 × AGB_i; CO2e_i = C_i × 44/12 / 1000 tonnes. Stock at the site S = sum over living trees of CO2e_i. Net removals over a period are the difference of stocks, with baseline and leakage zero under the stated conditions.
outputs and units of measure
Survival-adjusted carbon stock of living trees (TONNE of CO2e) by horizon, species, stratum, site and census place.
validation and verification approach
Not applicable in this release: the applicability condition refuses every application until a design carries the carbon module’s sections. Then: verification with the visit, a reviewer qualified in carbon accounting for afforestation and in field survey and data capture recomputing the stock from the diameters.
limitations and applicability boundaries
An allometric estimate for small-scale afforestation, not a measurement; above-ground biomass only, with no root-to-shoot ratio; the equation is generic across species; below the minimum diameter the estimate is noise. Meaningless before T3. Provisional: no design can apply it.
rationale
KIA-Adapt’s PDD (A3) computed carbon this way; the standard defines the methodology so that the carbon module is designed and its absence from 2026 claims is explicit rather than silent.
Applicability
- NCGS-M005 is provisional: it applies only under a design carrying the carbon module’s crediting-period and eligible-land sections, which no design carries in this release (ADR-0016).
Indicators it serves
Activity types
- Monitoring visit
Knowledge domains a reviewer needs
- Carbon accounting for afforestation
- Field survey and data capture
Variables
| Variable | Role | Unit | Description |
|---|---|---|---|
| Survival-adjusted carbon stock (S) | DerivedOutput | TONNE | S = sum over living trees of 0.47 × exp(-1.996 + 2.32 × ln(dbh_i)) × 44/12 / 1000 tonnes CO2e. |
| Stem diameter at breast height (dbh_i, cm) | MeasuredInput | CentiM | |
| Tree alive (a_i) | MeasuredInput | UNITLESS |
Monitoring requirements
- NCGS-M005 monitoring requirement: stem diameters at T3 or later under a carbon design: A stem diameter on every living tree above the species minimum on a visit at T3 or later; applicable only under a design with a crediting period, absent in this release.