Premium
Methane Production Explained Largely by Water Content in the Heartwood of Living Trees in Upland Forests
Author(s) -
Wang ZhiPing,
Han ShiJie,
Li HuanLong,
Deng FengDan,
Zheng YanHai,
Liu HaiFeng,
Han XingGuo
Publication year - 2017
Publication title -
journal of geophysical research: biogeosciences
Language(s) - English
Resource type - Journals
eISSN - 2169-8961
pISSN - 2169-8953
DOI - 10.1002/2017jg003991
Subject(s) - temperate climate , temperate forest , limiting , subtropics , environmental science , water content , methane , flux (metallurgy) , chemistry , botany , ecology , biology , geotechnical engineering , organic chemistry , mechanical engineering , engineering
Most forests worldwide are located in upland landscapes. Previous studies have mainly focused on ground methane (CH 4 ) flux in upland forests, and living tree stem‐based CH 4 processes and fluxes are thus relatively poorly understood. This study investigated the relationship between CH 4 concentration and water content in the heartwood of living trees in midtemperate, warm temperate, and subtropical upland forests and also measured seasonal changes of in situ stem CH 4 flux and the CH 4 concentration and water content in the heartwood of Populus davidiana Dode in a warm temperate upland forest. We found that approximately 4–13% of tree stems or approximately 8–31% of tree species had a substantial CH 4 concentration of ≥10,000 μL L −1 in their heartwood across the three types of upland forests. The heartwood CH 4 concentration was related to water content by a power function. A threshold of water content occurred beyond which CH 4 was produced at high levels in the heartwood. The CH 4 emissions from the breast height stems of P. davidiana ranged from 202.1 to 331.6 μg m −2 h −1 on a stem surface area basis during July–October 2016 and were significantly linearly correlated with the CH 4 concentration or water content in the heartwood throughout the experimental period, but the linear correlation was not significant at daily and monthly scales. Temperature was not a limiting factor for CH 4 production during July–October 2016, and thus, most of the CH 4 production may be explained by water content in the heartwood of living trees in upland forests.