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Mangrove Carbon Calculator
Enter stem circumference to calculate DBH and estimate mangrove biomass, carbon and CO₂ storage. A free field tool with optional soil, dead-wood and litter carbon, quadrat-linked GPS and offline access.
Developed byFaculty of Marine Sciences
Lasbela University of Agriculture, Water and Marine Sciences
Uthal · Balochistan · PakistanSESSION
Sampling sessions
Start with a blank dataset, or reopen your private survey file to continue fieldwork.
Private by default: every new calculator opens blank. Nothing is uploaded or automatically shown to another visitor. Save a project file to keep your working measurements, GPS and saved sessions; reopen that file on this or another device to continue. Keep the file private and save it again after making changes.
0 trees · 0 quadratsThe current dataset and GPS records stay in this tab until you save a survey file.
Current-tab session archive0 kept privately in this tab
No completed sessions are stored in this tab.
For offline fieldwork, keep this tab or installed app open while sampling. Download each CSV before closing; the calculator will deliberately open with a blank dataset next time.
01
Survey design
Define the sampled ground area and the forest area it represents.
Select a country to narrow the species choices for new tree records.
Based on Kew native ranges for species in this calculator, not a complete country checklist. Local occurrences and introduced stands may differ.Field presets
Total sampled0 m² · 0 ha
Forest coverage0%
Plots for 1% coverage0
Offline quadrat GPS registerCreate a quadrat to record its GPS location
Turn on phone Location and allow precise location for Chrome or this app. Offline GPS needs a satellite fix; try outdoors. You can always enter coordinates manually.QuadratTreesLatitudeLongitudeGPSStatusSampling
No quadrats or GPS coordinates yet. Create the first quadrat when field sampling begins.
Ready to begin sampling?
No single quadrat size is universal. Use consistent, randomly or systematically located plots across representative strata. The 10 × 10 m preset is convenient for DBH surveys; increase area where stems are sparse. “Plots for 1%” is a planning aid, not a statistical precision guarantee.
02
Tree measurements
Enter field-measured circumference. DBH is calculated automatically for every stem.
Active sampling locationNo quadrat selected 0 treesGPS coordinates not recorded
Create a quadrat to record its GPS location
Tree IDSpeciesStem circumference (cm)ρ (g/cm³)
No trees entered. Create a quadrat first.
Species presets use IPCC Annex 4A.3 mean wood densities. Select “Custom / other” and enter a locally verified density for species not listed or when stronger regional data are available.
Multi-stem measurement
If trunks separate below breast height, tap “+ stem” and enter the measured circumference of every stem separately at 1.3 m, or above its own highest root flare. The calculator converts each circumference to DBH, applies the allometric equation to each stem, and sums their biomass.
Dᵢ = Cᵢ ÷ πEach entered circumference is converted to DBH before biomass is calculated. Do not add stem circumferences or diameters together.Deq = √(D₁² + D₂² + … + Dₙ²)Equivalent DBH preserves combined stem basal area and is reported for inventory purposes. It is not substituted into the carbon equation.Btree = Σᵢ [0.251ρDᵢ2.46 + 0.199ρ0.899Dᵢ2.22]Then: Ctree = Btree × 0.47 · CO₂etree = Ctree × 44/1202A
Mangrove species field guide
Photographs are stored with the app for reference when the device is offline.
Aegiceras corniculatumρ preset: 0.6 g/cm³Photo: Vengolis · Wikimedia Commons · CC BY-SA 3.0ρ preset rounded from 0.597 g/cm³; source. Replace with a local measurement when available.Native range: Kew POWO
Photo reference only: confirm species using regional taxonomic keys, leaves, bark, flowers, fruits and root characters. Do not make a final identification from one photograph alone.
02B
Species carbon ratio
Biomass carbon is grouped by species; SOC is excluded because it cannot be assigned to individual trees.
SpeciesTreesMg C/hatCO₂e/haRatio
“Ratio” is the species’ percentage of measured living-biomass carbon in the sample. It reflects both stem abundance and DBH—not an inherent annual growth rate for the species.
Species-wise CO₂ storageCurrent stock + 0-year removal scenario
Current Modeled addition
0tCO₂e/ha
Storage durationHow long will each species continue?
Living biomass retains its carbon while the tree remains alive and after death only while its wood or transferred carbon pools remain unoxidized. Continued atmospheric removal cannot be dated from one DBH survey.
The displayed years are the selected planning horizon—not a predicted species lifespan. Confirm continued uptake using repeat DBH measurements; mangrove soil carbon can persist for centuries to millennia when undisturbed.
03
Soil organic carbon
SOC is excluded. Turn it on only when laboratory organic-carbon concentration, bulk density and sampled depth are available.
03A
Dead wood & litter carbon
Optional field/lab measurements, linked to each quadrat. DBH alone cannot estimate these pools.
Enter dry mass, not wet weight. Dead wood is the estimated dry biomass of standing and downed dead wood across the whole quadrat, determined with a documented inventory method (for example, measured volume × decay-adjusted density). Litter is oven-dry mass collected from a known total subplot area inside that quadrat. Enter 0 when a pool was surveyed and none was found; leave it blank when it was not sampled. Do not also enter dead trees as living trees.
How the calculation worksThe examples below use the default carbon fractions and a single sampled quadrat.
Weigh or estimate dry wood across the whole quadrat.
For large pieces, first estimate dry mass as wood volume (m³) × decay-adjusted dry density (kg/m³).
(total dry wood kg ÷ total measured quadrat m²) × carbon fraction × 10Worked example: 10 kg from one 10 × 10 m quadrat (100 m²) gives 10 ÷ 100 × 0.50 × 10 = 0.5 Mg C/ha.
Dry the collected litter and record its subplot area.
Add the area of all litter subplots within each quadrat. Use oven-dry mass, not wet field weight.
(total dry litter kg ÷ total collected subplot m²) × carbon fraction × 10Worked example: 0.2 kg from 1 m² gives 0.2 ÷ 1 × 0.45 × 10 = 0.9 Mg C/ha.
Why × 10? It converts kg/m² to Mg of carbon per hectare. For CO₂-equivalent, the app then multiplies carbon by 44/12. Across several quadrats, it adds measured masses and areas before dividing; blanks are not counted as zero.
Reference fractions: 50% for dead wood and 45% for mangrove litter, from the IUCN/Blue Carbon Initiative field manual. The inputs start at 0 so no coefficient appears to be a previous user's measurement. Select the reference fractions or enter measured local values before adding dry mass.
Dead woodNot sampled0 / 0 quadrats
LitterNot sampled0 / 0 quadrats · 0 m² collected
04
Whole-forest projection
A scenario based on your sampled forest stock, entered forest area and annual assumptions—not a measured future stock.
The year-0 stock comes from your quadrat measurements × entered whole-forest area. Enter a locally justified annual removal rate from repeat surveys, an inventory or an approved method; one-time DBH data cannot determine that rate. Each year, stock on lost area is subtracted proportionally; gained area starts with zero carbon and can accumulate removals in later years. The model assumes the same average stock and annual rate across the forest.
Method ledger
Every conversion is visible.
This is a screening and inventory tool. Formal REDD+ reporting still requires an approved forest definition, stratified sampling design, uncertainty analysis, quality control, reference level, safeguards and independent MRV.
Read the measurement and carbon-storage guide →- 01
Above-ground biomass
AGB = 0.251 × ρ × DBH^2.46Komiyama et al. mangrove allometry; result is kg dry biomass per tree.
- 02
Below-ground biomass
BGB = 0.199 × ρ^0.899 × DBH^2.22Mangrove root allometry; result is kg dry biomass per tree.
- 03
Equivalent multi-stem DBH
Deq = √(D₁² + D₂² + … + Dₙ²)A basal-area-equivalent structural diameter reported for inventory purposes.
- 04
Multi-stem tree biomass
Btree = Σᵢ [AGB(Dᵢ) + BGB(Dᵢ)]For n stems with diameters D₁…Dₙ, calculate each stem independently and sum the results. Equivalent DBH is not inserted into this equation.
- 04A
Circumference-to-DBH conversion
Dᵢ = Cᵢ ÷ πField staff enter each stem circumference. The calculator converts it to DBH before applying the allometric equations.
- 05
Carbon and CO₂
C = biomass × 0.47 · CO₂e = C × 44/12IPCC default carbon fraction and molecular conversion.
- 06
Soil organic carbon
SOC = bulk density × depth × C% × 100Returns Mg C/ha; coarse fragments are assumed absent unless corrected in source inputs.
- 07
Dead-wood carbon
Cdw = Σ dry mass (kg) ÷ Σ quadrat area (m²) × C fraction × 10Only quadrats with recorded dry dead-wood biomass are included. A recorded zero counts as sampled.
- 08
Litter carbon
Clitter = Σ dry mass (kg) ÷ Σ sampled subplot area (m²) × C fraction × 10Requires both dry litter mass and its actual collection area; blank entries are not treated as zero.
Primary guidance
About
Faculty of Marine Sciences
Lasbela University of Agriculture, Water and Marine Sciences
Uthal · Balochistan · PakistanMangrove Carbon Field Calculator
Developed to support transparent mangrove field inventories using circumference-derived DBH, species wood density, optional soil, dead-wood and litter carbon, quadrat GPS records and future CO₂-storage scenarios.
DBH & multi-stem measurementsSpecies field photographsOffline GPS quadrat registerOffline applicationCSV field-data exportIPCC · IUCN · REDD+ aligned workflow
This is a field-estimation and research-support tool. Results should be reviewed by qualified specialists before use in formal inventories, reporting or carbon-credit decisions.