Mapping Carbon in Kakamega

Acre Insights conducted a drone-based assessment of selected sample plots within the project site to estimate tree density, above-ground biomass (AGB), and indicative carbon stock.

Summary Metrics

Total Project Area 6.49 acres (≈ 2.63 ha)

Estimated Total Tree Count 5,348 trees

Average Tree Density ≈ 2,036 trees/ha

Total Above-Ground Biomass (AGB) 748.64 kg (0.75 tonnes)

Estimated Carbon Stock 374.32 kg C (0.37 tC)

Estimated CO₂e 1,373 kg CO₂e (1.37 t CO₂e)

Species Type Mixed species

Accuracy (indicative) ±15%

Spatial Insights

Acre Insights identified clear sample zones where young trees were visible in drone imagery in plot 1 and plot 2, as shown in Fig 1. Trees were counted within boundary boxes in the sample area, as shown in Figs. 2 and 3, and extrapolated to the entire project area.

The above-ground biomass (AGB) of trees was estimated using the pan-tropical allometric model developed by Chave et al. (2014), which incorporates diameter at breast height (DBH), total tree height, and wood density. The equation applied is:

AGB=0.0673⋅(ρ⋅D2⋅H)0.976

where D is DBH (cm), H is tree height (m), and ρ is wood density (g/cm³). For indigenous species, an average density of 0.60 g/cm³ was adopted. Ground data collected on sample trees had; D=2.5 cm, H=0.55 m, and ρ=0.60 g/cm3, the calculation proceeds as follows:

ρ⋅D2⋅H=0.60⋅(2.52)⋅0.55=2.06

AGB=0.0673⋅(2.06)0.976≈0.14 kg

Thus, each tree of this size contributes approximately 0.14 kg of above-ground biomass, with stand-level biomass obtained by summing across all individuals. This methodology ensures consistency with globally recognized standards for tropical forest carbon accounting (Chave et al., Global Change Biology, 2014).

Carbon & CO₂e Estimation

Aboveground biomass is converted to aboveground carbon stock using the IPCC-recommended carbon fraction:

CAGB=AGB×CF

where:

● CF is the carbon fraction of dry biomass

● A default value of 0.5 is commonly applied for the indigenous forest unless species-specific values are available

Carbon Stock = Biomass × 0.5

Carbon Stock = 784.64kg x 0.5= 392.32 kg

Carbon stock changes were converted to CO₂ sequestration by multiplying the net change in carbon stocks (kg C) by the IPCC molecular weight ratio of CO₂ to carbon (44/12 = 3.67), with positive values indicating net CO₂ removals.

CO₂e = Carbon × 3.67= 1,373 kg CO₂e (1.37 t CO₂e) since planting.

Interpretation

The project shows strong early-stage tree establishment density. Digital monitoring enables consistent tracking of growth and biomass accumulation.

Recommendations

- Capture planting records to enable survival-rate calculations

- Repeat monitoring every 6 months

Disclaimer

This report provides an indicative monitoring assessment and is not a certified carbon verification report.