DendroGeo Methods
How tree biomass, carbon stock, geodesic area and 10 m land-cover analysis are computed, with sources, uncertainty and limitations.
Open the DendroGeo appBiomass and carbon
Above-ground biomass follows the pantropical allometric equation of Chave et al. (2014): AGB = 0.0673路(蟻路D虏路H)^0.976, where field circumference C is measured with a tape at 1.30 m, D = C / 蟺 is the derived DBH (cm), H = height (m), and 蟻 is wood density (g/cm鲁) by species or group default. Raw circumference is retained; allometry uses the unrounded derived D, while DBH is displayed to one decimal place. Root biomass = AGB 脳 0.26; carbon = 0.47 脳 total biomass.
Location and area
Distances use the haversine formula on WGS84. Park areas use geodesic polygon mathematics; land-cover cells are intersected with the park polygon in the native UTM zone and only the true intersection area is counted (no pixel counting).
Land cover
The raw annual raster result uses ESA WorldCover 2021 v200 (10 m) and true raster-cell/park-polygon intersection areas. IO LULC 2020 is used as an independent cross-check only when a source comparison is run. Current analyses may also use Sentinel-2 L2A imagery (10 m or 20 m bands); the scene dates are recorded in the accepted analysis and report. Raw raster classes remain separate from the final user-accepted surface result. When enabled and accepted, OSM building, water and hard-surface geometries and user-drawn features contribute to that final result without rewriting the raw raster. Reports identify the source, period, resolution and accepted corrections.
Uncertainty
Field sigmas (circumference 卤0.5 cm, height 卤0.25 m) and a conservative 22% CV for the allometric model are propagated by Monte Carlo (n=1000, fixed seed); totals treat model error as correlated across records. Totals are reported with 95% confidence intervals where enabled.
Geofence and approval
Measurements require an approved park identity; the device position must fall inside the park polygon (40 m edge margin) or the server rejects the row (trigger trg_geo_fence). Every record enters the public dataset only after moderator approval.
Limitations
- WorldCover is 10 m; Sentinel-2 bands are 10 m or 20 m. Mixed or smaller features may not be separable at these resolutions.
- OSM completeness varies by place; manually accepted geometry depends on visual review.
- Chave (2014) is pantropical; regional bias for Turkish species is possible.
- Group-level wood density is used when species density is unavailable.