Elemental Stoichiometry of Tropical Peatland Trees: Implications for Adaptation and Carbon Sequestration †

Abstract

Indonesia has 13.43 million hectares of tropical peatlands, the largest in Southeast Asia, which are crucial for carbon sequestration. This function is influenced by vegetation nutrient content, particularly carbon (C), nitrogen (N), phosphorus (P), and potassium (K), which regulate biogeochemical cycles and peat formation. This study analyzed stoichiometric profiles of tree species in South Sumatra peatlands based on (1) C:N ratios across roots, stems, twigs, and leaves, and identified species with traits associated with high carbon sequestration potential, and (2) leaf N:P:K stoichiometry to infer nutrient limitations. Research was conducted in a 1-hectare primary peatland plot within the PT. Tri Pupa Jaya conservation area. C, N, P, and K contents were measured using Kjeldahl distillation, spectrophotometry, flame photometry, and the Walkley–Black method following acid digestion. Stoichiometric distribution was visualized with violin-box plots and species grouped through hierarchical clustering. Among 153 identified species, stems showed the highest mean C:N ratio (314.9 ± 210.8), while leaves had the lowest (29.7 ± 13.0). Species were grouped into three clusters by C:N ratios across four organs, with six in clusters 1 and 2 showing high carbon sequestration potential. Leaf N:P:K stoichiometry suggested nitrogen, phosphorus, or combined N + P limitations.