{"id":"land-cover","slug":"land-cover","name":"Forest, Cropland and Grassland Cover Dataset","description":"National land cover from FAO: forest area split into naturally regenerating, planted and primary forest, with cropland, arable land, permanent pasture and inland waters. Forest is observed at Global Forest Resources Assessment reference years — 1990, 2000, 2010, 2015, 2020 and 2025 — and the agricultural categories annually from 1961 for the countries that report them without imputation. Land cover is the slow variable underneath the rest of Hydrionis’ hydrology: what grows on a catchment governs how much rain reaches the ground, how much returns to the air, and how fast the rest runs off.","methodology":"Collected from the FAOSTAT land-use bulk domain, through the same fold as the crop and irrigation series. Every value carries a flag saying where it came from: official figures and figures from external organisations are stored as reported, FAO’s own estimates as estimated, and values imputed by a receiving agency are not stored at all. That rule is what produces the shape of the forest series — FAOSTAT publishes a forest figure for every year from 1990, but only the assessment years are observed and the rest are interpolated, so six points survive out of thirty-six and the gaps between them are left as gaps. Published in thousands of hectares and stored in hectares. Countries resolve through the UN M49-to-ISO3 crosswalk rather than by name; FAO’s own regional and world aggregates are excluded, including Sub-Saharan Africa, which carries an area code below the threshold the other aggregates sit above.","domains":["ecosystem","agriculture"],"metricIds":["forest-area","forest-area-naturally-regenerating","forest-area-planted","forest-area-primary","cropland-area","arable-land-area","pasture-area","inland-waters-area"],"subjectScope":"Countries, as held by Hydrionis; FAO aggregates and unresolvable areas excluded","cadence":"annual","version":"1.0.0","released":"2026-08-27","changelog":[{"version":"1.0.0","date":"2026-08-27","summary":"First release.","additions":["Four forest categories at six assessment years from 1990, three agricultural land-cover categories from 1961, and inland waters area."]}],"limitations":["These are land-use classes, not measurements of vegetation. Land felled, burned or temporarily unstocked but expected to regenerate is still counted as forest at its full area, so the forest series does not register a fire or a clear-cut — only a change of use. Readers looking for wildfire in a forest-area series are reading the wrong instrument.","Reported national statistics compiled from forest inventories and agricultural censuses, not remote sensing. Hydrionis holds no satellite vegetation series: the open products are gridded imagery requiring a spatial aggregation Hydrionis cannot validate, and the tabular ones sit behind registration gates.","The forest series has six observations across thirty-five years. No change in it can be dated more precisely than the interval it falls in, and a loss in 2003 is indistinguishable from one in 2009.","The four forest categories are nested, not independent: naturally regenerating and planted sum to forest area, and primary forest sits inside naturally regenerating. Adding them together counts most of the world’s forest twice.","Cropland, arable land and pasture are reported without imputation by roughly 85 of 234 countries, against about 228 for forest. The reporting countries are those with working agricultural statistics, which is a systematic bias rather than a random sample.","Permanent meadows and pastures is the least consistently defined category. Countries with large arid rangelands have revised it by tens of millions of hectares without the land changing.","Primary forest depends on a judgement about visible human disturbance that varies between countries and between assessments by the same country, so a step change may record a reassessment rather than a clearance.","Inland waters is reported without imputation by 77 of 234 countries, so a country missing from it is the usual case. It is not wetland extent — seasonally inundated ground, peat, marsh and floodplain are not counted, and a country can lose most of its wetlands with this figure unmoved — and it is not a volume.","No wetland extent series is held. SDG indicator 6.6.1 covers wetlands, mangroves and lake and river water area nationally and annually for about two hundred countries, and is refused on rights: the UN SDG data portal designates terms granting personal, non-commercial use only, with no right to redistribute or to create derivative works. The JRC Global Surface Water product behind its lake and river extents is licensed cleanly but published only as GeoTIFF tiles. The Ramsar list measures designated area, which is a policy act rather than a measurement of wetland.","FAO revises history. The whole series is republished each release, so figures cited previously may change."],"context":{"hydrionisClass":"water-driver","whyHeld":"Land cover is the boundary condition for a catchment’s water balance, and it is the one that changes slowly enough to be mistaken for a constant. Forest intercepts and transpires; tilled ground sheds; grassland sits between them. Holding it lets a rainfall or flow record be read against what the land was doing, rather than as though every catchment were the same surface.","waterRelevance":["Interception, evapotranspiration and infiltration, which land cover governs","The hydrological difference between primary forest and plantation, which a forest total conceals","Land-cover context for rainfall, drought and river-flow records","Where agricultural land, and so irrigation demand, actually sits"],"suitableUses":["National forest area and its composition at assessment years since 1990","Showing the conversion of primary or naturally regenerating forest to plantation within one country","Providing land-cover context alongside a rainfall, drought or flow series for the same country","Comparing agricultural land cover with the crop and irrigation series held beside it"],"unsuitableUses":["Any statement about a catchment, basin or particular forest — these are national totals","Reading a forest-area series as a record of tree cover, canopy loss, fire or logging","Presenting these as satellite or remotely sensed observations of vegetation","Interpolating between assessment years, or dating a forest change to a year within an interval","Summing the forest categories, which double-counts","Attributing a change in river flow to a change in land cover: nothing here establishes that link, and the catchment evidence for it comes from instrumented studies elsewhere","Comparing agricultural land cover across countries as though coverage were even; it is not","Reading inland waters area as wetland extent, or as a volume of water held"],"joinDimensions":[{"kind":"shared-identifier","on":"UN M49 country codes, mapped to ISO 3166-1 alpha-3 through the published UN crosswalk, then to Hydrionis country geographies","limitation":"Joins a country to a country and nothing finer. It does not place forest or cropland in a basin or a catchment, and Hydrionis holds no sub-national land-cover geography to place it in. A country half forested may have an entirely forested catchment beside an entirely cleared one."},{"kind":"time-only","on":"Shared calendar years with any other Hydrionis annual series","limitation":"The forest series exists at six years only, so an alignment with an annual hydrological record matches at six points and is absent between them. Nothing may be interpolated across the gap to make the join denser."}],"relationshipConfidence":"contextual","eligibility":{"api":true,"download":true,"overlay":true,"publicPage":false}},"observationCount":16336,"seriesCount":1278,"subjectCount":202,"from":1961,"to":2025,"sourceIds":["fao-faostat"],"units":["ha"],"redistributable":true,"commerciallyReusable":false,"rightsNote":"Redistribution is permitted by every contributing source.","citation":"Hydrionis (2026), Forest, Cropland and Grassland Cover Dataset, version 1.0.0. Retrieved from https://hydrionis.com/data/datasets/land-cover/","downloads":[{"file":"/downloads/observations-agriculture-fao-faostat.csv","format":"CSV","label":"agriculture observations from FAO (144,556 rows)"},{"file":"/downloads/observations-ecosystem-fao-faostat.csv","format":"CSV","label":"ecosystem observations from FAO (5,222 rows)"}],"apiPath":"/api/v1/datasets/land-cover.json","lastFetched":"2026-08-27","fields":[{"id":"forest-area","name":"Forest area","definition":"Land spanning more than 0.5 hectares with trees taller than 5 metres and a canopy cover above 10 per cent, or trees able to reach those thresholds in situ, where the predominant land use is not agricultural or urban.","unit":"ha","nativeGeography":["country"],"comparabilityNotes":"This is the whole of which the other three are parts: naturally regenerating and planted forest sum to it, and primary forest sits inside naturally regenerating. The categories are nested, so adding any of them to this total double-counts. A land-use class, not a measure of tree canopy. Land felled, burned or otherwise temporarily unstocked but expected to regenerate is still counted at its full area, so this series does not register a fire or a clear-cut — only a change of land use. Observed at Global Forest Resources Assessment reference years only — 1990, 2000, 2010, 2015, 2020 and 2025. Values FAO interpolates between assessments are not held, so the gaps are real gaps and no change can be dated more finely than the interval it falls in. A national total says nothing about the land cover of any particular basin. A country half forested may have an entirely forested catchment beside an entirely cleared one, and it is the catchment that governs the water. Definitions were harmonised across the assessment cycle, but earlier national inventories differed in how they treated open woodland and trees outside forests, so the longest comparisons are the weakest."},{"id":"forest-area-naturally-regenerating","name":"Naturally regenerating forest area","definition":"Forest predominantly composed of trees established through natural regeneration, including primary forest.","unit":"ha","nativeGeography":["country"],"comparabilityNotes":"Nested, not independent: this and planted forest sum to forest area, and primary forest is contained within this. Adding the categories together double-counts. A land-use class, not a measure of tree canopy. Land felled, burned or otherwise temporarily unstocked but expected to regenerate is still counted at its full area, so this series does not register a fire or a clear-cut — only a change of land use. Observed at Global Forest Resources Assessment reference years only — 1990, 2000, 2010, 2015, 2020 and 2025. Values FAO interpolates between assessments are not held, so the gaps are real gaps and no change can be dated more finely than the interval it falls in. A national total says nothing about the land cover of any particular basin. A country half forested may have an entirely forested catchment beside an entirely cleared one, and it is the catchment that governs the water."},{"id":"forest-area-planted","name":"Planted forest area","definition":"Forest predominantly composed of trees established through planting or deliberate seeding.","unit":"ha","nativeGeography":["country"],"comparabilityNotes":"Nested with naturally regenerating forest, which it sums with to give forest area; the two must not be added to the total. A land-use class, not a measure of tree canopy. Land felled, burned or otherwise temporarily unstocked but expected to regenerate is still counted at its full area, so this series does not register a fire or a clear-cut — only a change of land use. Observed at Global Forest Resources Assessment reference years only — 1990, 2000, 2010, 2015, 2020 and 2025. Values FAO interpolates between assessments are not held, so the gaps are real gaps and no change can be dated more finely than the interval it falls in. A national total says nothing about the land cover of any particular basin. A country half forested may have an entirely forested catchment beside an entirely cleared one, and it is the catchment that governs the water. That plantations can reduce low flows is a finding from instrumented catchments elsewhere, not something this national series demonstrates or could demonstrate."},{"id":"forest-area-primary","name":"Primary forest area","definition":"Naturally regenerated forest of native species where there are no clearly visible indications of human activity and the ecological processes are not significantly disturbed.","unit":"ha","nativeGeography":["country"],"comparabilityNotes":"A subset of naturally regenerating forest, never additional to it. A land-use class, not a measure of tree canopy. Land felled, burned or otherwise temporarily unstocked but expected to regenerate is still counted at its full area, so this series does not register a fire or a clear-cut — only a change of land use. Observed at Global Forest Resources Assessment reference years only — 1990, 2000, 2010, 2015, 2020 and 2025. Values FAO interpolates between assessments are not held, so the gaps are real gaps and no change can be dated more finely than the interval it falls in. A national total says nothing about the land cover of any particular basin. A country half forested may have an entirely forested catchment beside an entirely cleared one, and it is the catchment that governs the water. Assessing \"no clearly visible indications of human activity\" is a judgement that varies between countries and between assessments by the same country, so a step change in this series may record a reassessment rather than a clearance."},{"id":"cropland-area","name":"Cropland area","definition":"Land under temporary and permanent crops, including temporary meadows, market gardens and land temporarily fallow.","unit":"ha","nativeGeography":["country"],"comparabilityNotes":"Not harvested area. A field cropped twice in a year is one hectare of cropland and two hectares harvested, so harvested area can exceed cropland where multiple cropping is common and falls below it where land lies fallow. Reported without imputation by roughly 85 of 234 countries, against about 228 for forest. Those are the countries with working agricultural statistics rather than a random sample, so a cross-country comparison is partly a comparison of statistical capacity. A national total says nothing about the land cover of any particular basin. A country half forested may have an entirely forested catchment beside an entirely cleared one, and it is the catchment that governs the water."},{"id":"arable-land-area","name":"Arable land area","definition":"Land under temporary crops, temporary meadows for mowing or pasture, market and kitchen gardens, and land temporarily fallow.","unit":"ha","nativeGeography":["country"],"comparabilityNotes":"A subset of cropland, not an alternative measure of it: adding the two double-counts. The containment holds across all 3,953 published country-years where both are reported. What cropland has and this does not is permanent crops — orchards, vines, plantations — which Hydrionis does not hold as a separate series. Reported without imputation by roughly 85 of 234 countries, against about 228 for forest. Those are the countries with working agricultural statistics rather than a random sample, so a cross-country comparison is partly a comparison of statistical capacity. A national total says nothing about the land cover of any particular basin. A country half forested may have an entirely forested catchment beside an entirely cleared one, and it is the catchment that governs the water."},{"id":"pasture-area","name":"Permanent meadows and pastures area","definition":"Land used permanently, for five years or more, to grow herbaceous forage crops, whether cultivated or growing wild.","unit":"ha","nativeGeography":["country"],"comparabilityNotes":"The least consistently defined of these categories. Where the boundary falls between extensive rangeland, scrub and unused land is a national judgement, and countries with vast arid grazing land have revised this figure by tens of millions of hectares without the land changing. Reported without imputation by roughly 85 of 234 countries, against about 228 for forest. Those are the countries with working agricultural statistics rather than a random sample, so a cross-country comparison is partly a comparison of statistical capacity. A national total says nothing about the land cover of any particular basin. A country half forested may have an entirely forested catchment beside an entirely cleared one, and it is the catchment that governs the water."},{"id":"inland-waters-area","name":"Inland waters area","definition":"Area of inland water bodies — lakes, reservoirs and rivers — within a country’s boundaries.","unit":"ha","nativeGeography":["country"],"comparabilityNotes":"Not wetland extent. Wetlands include seasonally inundated ground, peat, marsh and floodplain that is not open water for most of the year, and none of that is counted here; a country can lose most of its wetlands with this figure unmoved. Not a volume either — a shallow lake and a deep one of equal surface hold vastly different amounts of water, and this measures neither depth nor flow. Reported by 77 of 234 countries without imputation, so the absence of a country is the usual case rather than the exception. Where a country reports, the figure is almost always official: 1,227 of 1,237 held values."}]}