Comparison of ground biomass for carbon measurement and management in persimmon plantation at Mae Hae Royal Project

Abstract

Persimmon (Diospyros kaki) plantations within the Mae Hae Royal Project contribute to global climate mitigation goals. The study aims to assess and compare the total carbon stock and CO<inf>2</inf> sequestration potential to inform carbon credit certification and support sustainable management practices. The study followed national carbon accounting guidelines under the Thailand Voluntary Emission Reduction Program (T-VER). Fifty-three sample plots, representing 1.03% of the 999 rai plantation area, were randomly selected and stratified by age class and ground cover type. Biomass was calculated using allometric equations, based on measured girth at breast height (GBH) and tree height. Carbon stocks and CO<inf>2</inf> sequestration were assessed using the IPCC standard carbon ratio (0.47). Across the sampled plots, total CO<inf>2</inf> sequestration amounted to 154.46 tCO<inf>2</inf>e with the entire project area estimated to sequester 15,005 tCO<inf>2</inf>e. Above-ground biomass was the dominant contributor (82.47%) to total carbon stock. Orchards with organic management and those with natural grasses recorded the highest carbon stocks (21.31 and 20.75 tCO<inf>2</inf>e /rai). Furthermore, mature trees (≥ 20 years) showed higher carbon accumulation (up to 19.50 tCO<inf>2</inf>e /rai) compared to younger or mixed-age plots. Persimmon plantations at the Mae Hae Royal Project function as important regional carbon sinks, especially under organic and natural grass cover. These findings provide essential quantitative data to support the project's participation in carbon credit certification and trading schemes, demonstrating a viable pathway for balancing community livelihoods with national CO<inf>2</inf> mitigation and net-zero emission goals.