• Trees are known to emit methane (CH₄) and nitrous oxide (N₂O), with tropical wetland trees being considerable CH₄ sources. Little is known about CH₄ and especially N₂O exchange of trees growing in tropical rain forests under nonflooded conditions.
• We determined CH₄ and N₂O exchange of stems of six dominant tree species, cryptogamic stem covers, soils and volcanic surfaces at the start of the rainy season in a 400‐yr‐old tropical lowland rain forest situated on a basaltic lava flow (Réunion Island). We aimed to understand the unknown role in greenhouse gas fluxes of these atypical tropical rain forests on basaltic lava flows.
• The stems studied were net sinks for atmospheric CH₄ and N₂O, as were cryptogams, which seemed to be co‐responsible for the stem uptake. In contrast with more commonly studied rain forests, the soil and previously unexplored volcanic surfaces consumed CH₄. Their N₂O fluxes were negligible.
• Greenhouse gas uptake potential by trees and cryptogams constitutes a novel and unique finding, thus showing that plants can serve not only as emitters, but also as consumers of CH₄ and N₂O. The volcanic tropical lowland rain forest appears to be an important CH₄ sink, as well as a possible N₂O sink.

中文翻译：

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在火山留尼汪岛的低地热带雨林中，树木作为甲烷（CH4）和一氧化二氮（N2O）的净汇

• 已知树木会排放甲烷（CH ₄）和一氧化二氮（N ₂ O），而热带湿地树木是大量CH _4的来源。对于非淹没条件下热带雨林中生长的树木的CH ₄交换，尤其是N ₂ O交换，人们知之甚少。
• 我们确定了雨季开始时，在玄武岩熔岩流上的一个400年历史的热带低地雨林中，六种优势树种，隐花茎被覆，土壤和火山表面的茎的CH ₄和N ₂ O交换（留尼旺岛）。我们旨在了解玄武岩熔岩流对这些非典型热带雨林温室气体通量的未知作用。
• 所研究的茎是大气中CH ₄和N ₂ O的净汇，隐孢子虫也似乎是茎吸收的共同负责者。与更常研究的雨林相反，土壤和以前未开发的火山表面消耗CH ₄。它们的N ₂ O通量可以忽略不计。
• 树木和隐藻的温室气体吸收潜力构成了一个新颖而独特的发现，从而表明植物不仅可以充当排放者，而且可以充当CH ₄和N ₂ O的消费者。火山热带低地雨林似乎是重要的CH _4个水槽，以及一个可能的N ₂ O水槽。