Foliar Methane and Nitrous Oxide Fluxes: A Comprehensive Study in Tropical Forest Ecosystems

• DOI: 10.5194/egusphere-egu24-11673
• Publication Date: 2024-03-08T22:29:45Z
• Authors: Khandaker Mohamme...; Md Abdul Halim; Sean Thomas
• Keywords: Nitrous oxide; Tropical forest; Atmospheric methane; Methane Emissions

Comprising 45% of global forest cover, tropical forests are pivotal in the GHG budgets. Emerging research highlights significance trees as CH4 sources, yet tree-foliage emissions have been minimally investigated. Moreover, N2O fluxes from tree foliage remain almost completely unexamined. Objectives: This study presents a comprehensive survey foliar and across species using integrated output spectroscopy purpose-built cuvette system for accurate in-situ flux rate measurements. It tests two key hypotheses: (1) broadleaf well-drained soils exhibit oxidation; (2) patterns vary systematically among ecological phylogenetic groups. Methods: We measured 120 40 within Lawachara National Park, Bangladesh, an upland mixed-tropical-evergreen forest, prioritizing diverse shade-tolerant canopy trees. utilized dynamic leaf chamber (CS-LC7000) with continuous gas flow portable (LGR 915-001) (LI-7820) analyzers, alongside concurrent measurements CO2 H2O flux. In addition to data, our incorporated trait (of mass per area N content). Results: Across all samples, mean 0.016 nmol m-2 s-1 did not display significant deviation zero (t = 19.44, df 827, p > 0.05). contrast, 0.54 s-1, exhibited elevation above 19.42, < 0.001), indicating notable on average. Methane varied various successional groups, namely pioneer, mid-successional, late (F 5.99, 2, 0.01). Pioneer species, which were sources CH­4, demonstrated significantly higher compared both mid (p 0.01) 0.05) acted weak sinks. All groups N2O, variations 12.97, identified highest emitters followed by late-successional species. A comparative analysis 28 families revealed variability 47.7, 27, 0.01), certain acting others sinks CH4. Notably, 11 classified while remainder functioned Meliaceae emerged having average emissions, Thymeliaceae greatest consumption. Similarly, distinct variation was observed 6.57, Sapindaceae showing highest, Rubiaceae Euphorbiaceae lowest emissions. Conclusions: reveals trees' crucial role greenhouse emerge major suggesting that these GHGs may be pronounced secondary forests, hence importance conserving intact dominated later-successional