School of Biosciences, The University of Nottingham, Sutton Bonington, Loughborough, LE12 5RD, UK.
Department of Environment, Earth & Ecosystem Sciences, STEM Faculty, The Open University, Milton Keynes, MK7 6AA, UK.
New Phytol. 2020 Jan;225(2):769-781. doi: 10.1111/nph.16178. Epub 2019 Oct 25.
Neotropical peatlands emit large amounts of methane (CH ) from the soil surface, but fluxes from tree stems in these ecosystems are unknown. In this study we investigated CH emissions from five tree species in two forest types common to neotropical lowland peatlands in Panama. Methane from tree stems accounted for up to 30% of net ecosystem CH emissions. Peak CH fluxes were greater during the wet season when the water table was high and temperatures were lower. Emissions were greatest from the hardwood tree Campnosperma panamensis, but most species acted as emitters, with emissions declining exponentially with height along the stem for all species. Overall, species identity, stem diameter, water level, soil temperature and soil CH fluxes explained 54% of the variance in stem CH emissions from individual trees. On the landscape level, On the landscape level, the high emissions from C. panamensis forests resulted in that they emitted at 340 kg CH d during flooded periods despite their substantially lower areal cover. We conclude that emission from tree stems is an important emission pathway for CH flux from Neotropical peatlands, and that these emissions vary strongly with season and forest type.
新热带泥炭地从土壤表面排放大量甲烷（CH ），但这些生态系统中树干的通量尚不清楚。在这项研究中，我们调查了巴拿马两种新热带低地泥炭地常见森林类型中 5 种树木的 CH 排放。树干中的 CH 占净生态系统 CH 排放的 30%。当水位高且温度较低时，雨季的 CH 通量峰值更大。硬木树种 Campnosperma panamensis 的排放量最大，但大多数树种都是排放源，所有树种的排放量随树干高度呈指数下降。总的来说，物种特性、茎直径、水位、土壤温度和土壤 CH 通量解释了单个树木树干 CH 排放变化的 54%。在景观水平上，尽管 Campnosperma panamensis 林的面积覆盖率低，但由于其高排放量，导致在洪水期排放了 340kg CH d 。我们的结论是，树干排放是新热带泥炭地 CH 通量的一个重要排放途径，这些排放强烈地随季节和森林类型而变化。
