Aboveground Biomass and Carbon Stock of Trees and Poles in Tropical Peatland Forest Ecosystems: A Case Study from Riau, Indonesia

¹ Universitas Lancang Kuning, Forestry Department, Faculty of Forestry, 28261 Pekanbaru, Indonesia
² Universitas Riau, Faculty of Fisheries, 28295 Pekanbaru, Indonesia
³ Universitas Lancang Kuning, Architecture Department, Faculty of Engineering, 28261 Pekanbaru, Indonesia
⁴ Institut Pertanian Stiper, Forestry Department, Faculty of Forestry, 55281 Yogyakarta, Indonesia

^* Corresponding author: srirahayupn@unilak.ac.id

Abstract

Tropical peatland forests play a vital role in carbon storage and global climate regulation but are increasinglv threatened bv degradation and land-use change. This study aims to analyze aboveground biomass (AGB), carbon stock, CO₂ sequestration potential, and tree volume across two forest management zones rehabilitation and conservation within PT Diamond Raya Timber, Riau, Indonesia. Data were collected from 30 - 50 plots representing two growth stages (poles and trees) using allometric models. The results showed that the conservation zone presented higher values across all parameters. At the pole stage, AGB, carbon, and CO₂ were 393.59, 184.99, and 678.95 t ha⁻¹, respectively, compared to 185.77, 87.31, and 320.43 t ha⁻¹ in the rehabilitation zone. Similarly, at the tree stage, the conservation zone recorded 5,746.07 t ha⁻¹ AGB, 2,700.65 t ha⁻¹ carbon, and 9,991.40 t ha⁻¹ CO₂, which were significantly higher than 2,900.03, 1,363.02 , and 5,002.27 t ha⁻¹ in the rehabilitation zone. Tree volume estimation followed the same pattern. The total stand volume in the conservation zone reached 2,183.53 m³ ha⁻¹ (poles) and 8,775.36 m³ ha⁻¹ (trees), whereas in the rehabilitation zone it was only 960.12 m³ ha⁻¹ (poles) and 4,049.64 m³ ha⁻¹ (trees). These findings highlight that stand structure and management history strongly influence biomass accumulation and carbon dynamics. Conserving intact peat forests and restoring degraded zones through hydrological recovery and enrichment planting are essential strategies for enhancing carbon sink capacity and achieving Indonesia's FOLU Net Sink 2030 targets.