Managed fire in the NT, 2000–2025

How each year's figures were produced — reproducible from the public NAFI fire-scar archive and the ACCU carbon-project register.

1. Fire data. NAFI monthly fire-scar shapefiles (250 m), one per year 2000–2025, from firenorth.org.au. Each polygon is a burnt patch tagged with the month it burnt.
2. NT land selection. Each year's fire is clipped to a longitude/latitude box (129°E–138°E, south to ~26°S, open to the coast in the north). NAFI's own region attribute is unreliable — absent before 2013, compound strings like “(a) NT (b) WA” in 2015–21, mapping-block codes in 2025 — whereas the NT's borders are meridians and a parallel and there is no fire at sea, so the box selects NT land exactly and identically every year.
3. Projects. ACCU project-area polygons where the method type begins “Savanna” and status is Declared. For each year only projects registered on or before that year are counted (a time-varying footprint), so managed area is never credited before a project existed.
4. Managed fire. The NT fire layer intersected with the union of that year's active project boundaries; everything outside is “unmanaged”.
5. Season. Month ≤ July = early dry season; August onward = late dry season — the damaging wildfire window that early burning is meant to pre-empt.
6. Measurement. All areas are computed in an equal-area projection (GDA94 Australian Albers, EPSG:3577) and reported in km²; geometries are repaired with a zero-width buffer first.
7. The two ratios. Managed share = managed ÷ all NT fire. Late-season managed share = managed-late ÷ all late-season NT fire — different denominators, which is why the two lines in chart 1 aren't slices of one whole.

These are lifted directly from the analysis script's own header. They decide how the figures should and shouldn't be read.

• Denominator is all NT land fire (a lon/lat box: 129°E–138°E, north of ~26°S). That's the "all-NT" figure — a floor. The method-eligible savanna-zone denominator (a rainfall mask) would be smaller, so the true managed fraction of eligible country is higher.
• NAFI 250 m under-detects small, patchy early-season fires — which are exactly the management fires. So managed area, and every managed fraction, is a lower bound. Validate against Sentinel-2 on sample project-years before quoting hard numbers.
• Project footprint is "current" boundaries (STATUS = Declared, registered ≤ that year). The register lacks historical revocation dates, so earlier years are slightly over-counted.
• Early/late boundary is month ≤ July = early. The real EDS/LDS cut-off (~31 Jul) is method- and zone-specific; this is an approximation.
• Pre-2012 zeros are real, not missing data — no ACCU savanna projects were registered before 2012 (earliest registration 2012; 1 project that year, 3 in 2013, 85 by 2025).