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Long‐term stem CO 2 concentration measurements in N orway spruce in relation to biotic and abiotic factors
Author(s) -
Etzold Sophia,
Zweifel Roman,
Ruehr Nadine K.,
Eugster Werner,
Buchmann Nina
Publication year - 2013
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/nph.12115
Subject(s) - abiotic component , picea abies , respiration , environmental science , soil respiration , biogeochemical cycle , botany , atmospheric sciences , ecology , biology , chemistry , physics
Summary Stem CO 2 concentrations (stem [ CO 2 ]) undergo large temporal variations that need to be understood to better link tree physiological processes to biosphere–atmosphere CO 2 exchange. During 19 months, stem [ CO 2 ] was continuously measured in mature subalpine N orway spruce trees ( P icea abies ) and jointly analysed with stem, soil and air temperatures, sap flow rates, stem radius changes and CO 2 efflux rates from stem and soil on different time scales. Stem [ CO 2 ] exhibited a strong seasonality, of which over 80% could be explained with stem and soil temperatures. Both physical equilibrium processes of CO 2 between water and air according to H enry's law as well as physiological effects, including sap flow and local respiration, concurrently contributed to these temporal variations. Moreover, the explanatory power of potential biological drivers (stem radius changes, sap flow and soil respiration) varied strongly with season and temporal resolution. We conclude that seasonal and daily courses of stem [ CO 2 ] in spruce trees are a combined effect of physical equilibrium and tree physiological processes. Furthermore, we emphasize the relevance of axial diffusion of CO 2 along air‐filled spaces in the wood, and potential wound response processes owing to sensor installation.