Indigenous and community land-tenure mapping for carbon project additionality
Carbon additionality claims in REDD+ projects require proof that deforestation pressure is real and that existing legal tenure does not already secure the forest. Multi-temporal SAR and optical change detection, layered against cadastral and concession data, provides that evidence in a form registries can audit.
Sensors
- Sentinel-1 SAR (C-band): 10-metre spatial resolution, 6-day repeat at the equator with both satellites active. C-band backscatter penetrates cloud cover year-round, making it the primary tool for detecting canopy removal in persistently cloudy tropical regions. Sensitive to structural change rather than phenological variation, which reduces false positives from seasonal drought stress.
- Sentinel-2 MSI: 10-metre resolution in visible and near-infrared bands, 5-day revisit (combined constellation). NDVI and NBR indices track canopy condition. Cloud cover is the hard constraint in humid tropics; optical confirmation of SAR-flagged events typically requires compositing over 30-90 days to achieve cloud-free coverage.
- Planet SkySat: 50-centimetre panchromatic, approximately 1-metre multispectral, tasked on demand. Used for sub-parcel boundary verification and to document encroachment features such as field berms, access tracks and temporary structures that are below Sentinel resolution. Not a systematic monitoring tool; cost constrains it to targeted confirmation tasks.
- Global Forest Watch concession and protected-area layers: Polygon datasets covering industrial concessions, protected areas and, where governments have published them, indigenous territorial boundaries. Spatial accuracy varies by country and data vintage; some national cadastres have positional errors of hundreds of metres. These layers define the legal context into which change-detection outputs are placed, not a source of ground truth on their own.
- Landsat Collection 2 (USGS): 30-metre resolution, 16-day revisit per satellite, archive from 1972. The long record is essential for constructing the 10-year or longer historical deforestation-rate baselines that Verra's VM0015 and VM0007 methodologies require. Landsat and Sentinel-2 are spectrally cross-calibrated, allowing continuous time series across both missions.
Why additionality is harder than it looks on a tenure map
Verra's REDD+ methodologies and the Gold Standard's Land Use and Forests framework both require a project to demonstrate that the carbon it claims to protect would, in the absence of the project, have been lost. The standard approach is to show a credible historical deforestation rate and an ongoing threat. Where indigenous or community tenure exists on paper, a validator may reasonably ask: does the legal protection already prevent that threat? If so, the project may not be additional.
The problem is that formal tenure and effective protection are frequently different things. A community may hold a title that is contested by a concession holder, encroached by smallholders clearing for subsistence, or simply not enforced by a state with limited capacity. Satellite change detection can document the gap between what the legal record says and what the landscape shows. That gap is the additionality argument, expressed in hectares and dates rather than assertions.
Building the encroachment pressure record
The analytical workflow begins with a multi-temporal forest-cover change stack. Landsat Collection 2 imagery, processed through the USGS surface-reflectance product, provides annual or biennial snapshots back to the early 1990s. Sentinel-2 extends the series at finer resolution from 2017. Sentinel-1 SAR fills the cloud-gap years in humid tropical zones where optical data is seasonally unusable. Together they produce a pixel-level loss chronology that can be compared against the date a community tenure claim was lodged, a concession boundary was drawn, or a protected-area gazette notice was issued.
The output is not simply a deforestation map. It is a dated sequence showing whether clearance accelerated before or after a legal event, whether it is concentrated at tenure boundaries, and whether the pattern is consistent with industrial clearing (large, geometrically regular polygons) or smallholder encroachment (irregular, finger-shaped incursions along tracks). These spatial signatures carry methodological weight: Verra's VM0007 v1.6 and the jurisdictional REDD+ framework both accept satellite-derived historical reference data when it is documented with sufficient traceability.
What a floating roof gives away, and what it cannot
Sentinel-1 C-band backscatter responds to changes in canopy structure. When trees are felled, the return signal from the forest floor increases sharply, typically detectable within one to two repeat cycles, so within 6 to 12 days at the equator. That makes SAR the fastest systematic detector of new clearance in cloudy regions. At 10-metre resolution it can resolve clearings of roughly 0.1 hectares and larger with reasonable confidence, though accuracy degrades for narrow linear features such as access tracks.
What SAR cannot do is resolve sub-parcel tenure boundaries or distinguish between a community member clearing within their own plot and an external encroacher crossing a boundary. That distinction requires either high-resolution optical imagery (SkySat at 50 centimetres can show field berms and structure footprints) or ground-truth from community rangers. The satellite record establishes that change happened, where, and when. Attributing it to a specific actor or tenure category requires corroborating evidence. Presenting satellite data as proof of external encroachment without that corroboration is a methodological overreach that experienced validators will flag.
Cadastral overlay and the positional accuracy problem
Layering change-detection outputs against concession boundaries and indigenous territorial polygons is standard practice, but the positional accuracy of those polygons is frequently poor. National cadastres in many tropical countries were digitised from paper maps at 1:50,000 or 1:100,000 scale, introducing boundary uncertainties of 50 to 500 metres. A clearing that appears to cross a tenure boundary in a GIS overlay may simply reflect cadastral error rather than actual encroachment.
The honest approach is to report a buffer zone around all boundary-crossing events and to quantify the positional uncertainty of the cadastral source. Where indigenous territorial boundaries have been demarcated by GPS survey, positional accuracy is typically sub-10 metres and the overlay is meaningful. Where boundaries come from a scanned colonial-era map, the overlay is indicative at best. Carbon project documentation should state which regime applies, and auditors should ask.
Structuring the evidence package for registry submission
Verra's VCS programme and the Gold Standard both accept remotely sensed data as primary evidence when it is accompanied by documented processing chains, sensor metadata, and uncertainty estimates. A submission-ready package typically contains: a georeferenced forest-cover change raster with per-pixel confidence scores; a vector layer of discrete change events with area, date range and spectral or backscatter evidence; a comparison of change rates inside and outside the project boundary; and a narrative linking the spatial pattern to the tenure context drawn from cadastral and concession sources.
The time series depth matters. A 10-year pre-project baseline is a common minimum; some methodologies require 20 years. Landsat's archive from 1972 means that baseline depth is achievable for most tropical project areas, though cloud-affected years may require gap-filling with SAR or interpolation, both of which should be disclosed. Satellize structures these packages to meet the traceability standards that third-party auditors expect, drawing on the same open-constellation data that validators can independently re-run.
A note on what the package cannot resolve: informal sub-community tenure, overlapping customary claims within a single indigenous territory, and the difference between temporary agricultural use and permanent conversion are all poorly served by current satellite resolution. These require participatory mapping and community-level documentation. The satellite evidence is strongest for the boundary-scale and landscape-scale questions; it is weakest for the intra-community ones.
Honest limits, and where the method still earns its place
No satellite system currently operational can reliably detect clearings below about 0.05 to 0.1 hectares in tropical forest. Selective removal of individual trees, which is common in smallholder encroachment, may not cross the detection threshold until cumulative loss is visible in a seasonal composite. Persistent cloud in equatorial regions can delay optical confirmation by months. SAR is cloud-immune but requires careful filtering to separate genuine forest loss from flood inundation, which produces a similar backscatter signature.
Despite these limits, the method fills a gap that no other approach addresses at scale. Community land rangers cannot patrol every boundary every week. Legal processes move slowly and often lack spatial documentation. A satellite time series that shows clearance accelerating toward a community boundary, dated to within a fortnight, is objective evidence that no affidavit can replicate. For carbon project additionality, the question is not whether satellite data is perfect. It is whether it is more credible than the alternative, which is often nothing at all.
Typical figures
| Spatial resolution (SAR change detection) | 10 m (Sentinel-1 IW mode) |
| Spatial resolution (optical change detection) | 10 m Sentinel-2; 30 m Landsat; 50 cm SkySat for targeted confirmation |
| Revisit frequency | 6 days SAR (Sentinel-1 A+B at equator); 5 days optical (Sentinel-2 A+B); 16 days Landsat per satellite |
| Minimum detectable clearing | Approximately 0.05 to 0.1 ha for contiguous loss; smaller events unreliable at Sentinel resolution |
| Historical archive depth | Landsat from 1972; Sentinel-2 from 2015; Sentinel-1 from 2014 |
| Cloud-gap mitigation | Sentinel-1 SAR provides cloud-immune structural change signal; optical compositing over 30-90 day windows for humid tropics |
| Cadastral overlay accuracy | Dependent on source; GPS-demarcated indigenous boundaries sub-10 m; scanned national cadastres 50-500 m positional uncertainty |
| Delivery format | GeoTIFF change rasters, GeoPackage or Shapefile vector events, PDF narrative report, XLSX uncertainty tables |
| Processing latency (operational monitoring) | SAR-based alerts within 24-48 hours of scene acquisition; optical confirmation within 7-30 days depending on cloud |
| Registry compatibility | Processing chain documented to Verra VCS and Gold Standard traceability requirements; independent re-run possible from open data |
Analytics Satellize can run
| Historical deforestation rate baseline | Multi-temporal forest-cover classification using Landsat Collection 2 and Sentinel-2 surface reflectance, following IPCC Tier 1/2 land-use change accounting conventions | Annual forest-cover change raster stack with area statistics per stratum, formatted for Verra VM0007 or VM0015 baseline tables |
| Encroachment pressure index | Spatial density analysis of discrete clearing events within user-defined buffer zones around tenure boundaries, derived from SAR and optical change stack | GIS polygon layer with per-boundary encroachment rate (ha/year), trend direction and statistical confidence interval |
| Tenure-boundary crossing event log | Overlay of dated change polygons against cadastral and concession boundary datasets, with positional uncertainty buffer applied per source quality class | Tabular event log with coordinates, area, date range, sensor provenance, boundary source and uncertainty flag; exportable to Excel or GeoPackage |
| SAR-based near-real-time clearing alerts | Sentinel-1 coherence change and backscatter anomaly detection, calibrated against local forest type to reduce flood false-positives | Weekly alert feed (GeoJSON or KML) showing new potential clearing events, with confidence score and optical confirmation status |
| High-resolution encroachment confirmation imagery | Targeted SkySat tasking over SAR-flagged events, with manual feature interpretation for tracks, berms, structures and field boundaries | Annotated image report (PDF) with feature inventory and sub-parcel boundary sketch, suitable for inclusion in project validation documentation |
| Registry-grade evidence package | Compilation of change rasters, vector event layers, uncertainty tables and narrative methodology statement per Verra VCS or Gold Standard documentation requirements | Structured submission folder with all required metadata, processing-chain documentation and auditor re-run instructions |
Who does the work
We can get this done for you. Satellize runs its own analyst desk and a strong science team. You do not buy a data feed and work out what it means; our people source the imagery, run the analysis described on this page, and hand you the answer with its confidence limits stated. Discuss this requirement.