Stand age determines which growth curve applies, whether the area was eligible when planting began, when the crediting period starts, and whether measured biomass is plausible. In smallholder ARR programmes it is frequently the least carefully recorded fact in the project, often reconstructed later from farmer recollection and a planting budget.
What Depends on It
| Depends on planting year | How badly it breaks if wrong |
|---|---|
| Growth curve selection | Wrong curve, wrong projection, compounding |
| Eligibility (land condition at start) | Project may not qualify at all |
| Crediting period start | Credits claimed for ineligible periods |
| Plausibility of measured stock | Measurements look anomalous, findings follow |
The second row is the severe one. If eligibility depends on the land being non-forest at a cut-off date, and the planting date is uncertain, the eligibility argument inherits that uncertainty.
Why It Goes Wrong in Smallholder Programmes
Planting happens across hundreds of small parcels over a season, often by farmers themselves, and sometimes before any carbon programme existed. Records get made for operational reasons, such as seedlings distributed or payments made, but not for evidentiary ones.
Three common gaps:
Distribution ≠ planting. A record showing 400 seedlings issued to a farmer in March does not establish that they were planted, when, or where. Survival and actual planting date are separate facts.
Phased planting recorded as one date. A parcel planted over two seasons, recorded as a single year, produces a stand whose measured variation looks like measurement error and is actually age structure.
Replanting overwriting the original. Failed areas replanted later, with the record updated rather than appended, so the parcel now claims an age it does not have.
What an Adequate Record Contains
Parcel identifier, planting date or date range, species and quantity, who planted, and a link to the seedling batch. Where planting was phased, the phases separately.
That is a small amount of information. It has to be captured at the time, because every route to reconstructing it later, including farmer recall, satellite imagery, or growth back calculation, is either imprecise or circular.
Back-calculating age from measured size is the circular one and it appears in real project documents: the growth model is used to infer the age, and the age is then used to apply the growth model.
Where Imagery Helps and Where It Does Not
High-resolution historical imagery can establish that a parcel was bare at one date and planted by another. That brackets the planting date, which is genuinely useful for eligibility.
It cannot distinguish a parcel planted in March from one planted in September, and in a fast-growing tropical planting that half-year matters for early growth modelling. Imagery constrains; it does not substitute for the record.
The Cheap Fix
A planting register maintained as planting happens, with the fields above, linked to the parcel geometry.
Programmes that build this find their growth modelling straightforward and their eligibility evidence solid. Programmes that skip it spend the equivalent effort three years later producing something weaker, at a point when the people who did the planting have moved on.
Track what happens after planting
Survival rate is the assumption that quietly decides a restoration forecast. TREEO Dashboard monitors planting cycles and tracks survival so the number you report is the number you measured.
