Stem CO2 efflux, growth respiration and stem increment of beech and spruce trees

0562080 - ÚVGZ 2023 SI eng A - Abstrakt
Dařenová, Eva - Krejza, Jan
Stem CO2 efflux, growth respiration and stem increment of beech and spruce trees.
Plants in Changing Environment. Ljubljana: Slovenian Society of Plant Biology, 2022 - (Baebler, Š.; Dermastia, M.; Grebenc, T.; Praprotnik, E.; Razinger, J.; Urbanek Krajnc, A.). s. 62. ISBN 978-961-91014-5-2.
[Plants in Changing Environment. 15.09.2022-16.09.2022, Ljubljana]
Grant CEP: GA MŠMT(CZ) EF16_019/0000797; GA MŠMT(CZ) LM2015061
Institucionální podpora: RVO:86652079
Klíčová slova: stem respiration * cell wall thickening * carbon
Obor OECD: Forestry

Stem respiration is an important component of an ecosystem’s carbon budget. It provides energy for living tissue maintenance and growth processes, and it returns a part of carbon allocated to the stem back to the atmosphere as CO2. Besides environmental factors (such as temperature or water availability), stem respiration depends highly on tree energy demands for stem growth. Determining the relationship between stem growth and stem respiration would help to reveal the response of stem respiration to changing climate, which is expected to substantially affect tree growth. In this study, we measured stem CO2 efflux and irreversible tree stem increment of beech and spruce trees during four growing seasons (May – October) at two different sites. Stem CO2 efflux was measured using automated chamber systems and stem increment using automated dendrometers, both installed at the breast height. Then the respiration needed for stem growth was estimated using the mature tissue method. Seasonal stem CO2 efflux amounted to between 690 and 1100 g CO2 per m-2 of the stem surface. The seasonal stem CO2 efflux of spruce was higher compared to the beech as well as seasonal irreversible stem increment. The proportion of seasonal growth respiration to total stem CO2 efflux ranged between 38-70% and, despite bigger increment, it tended to be slightly lower in spruce compared to beech. The highest growth respiration was observed in June and July in beech and in July and August in spruce, with maximum contribution to monthly stem CO2 efflux of 92 and 73%, respectively. The growth respiration showed a time lag behind stem increment. The regression between growth respiration in the irreversible increment, therefore, differed during the period before and after the maximum stem increment rate. We consider this to be a result of the later onset of stem wall thickening which, we assume, is more energetically demanding than is cell elongation.
Trvalý link: https://hdl.handle.net/11104/0334500