Sammanfattning

Forests accumulate much less carbon than the amount fixed through photosynthesis because of an almost equally large opposing flux Of CO(2) from the ecosystem. Most of the return flux to the atmosphere is through soil respiration, which has two major sources, one heterotrophic (organisms decomposing organic matter) and one autotrophic (roots, mycorrhizal fungi and other root-associated microbes dependent on recent photosynthate). We used tree-girdling to stop the flow of photosynthate to the belowground system, hence, blocking autotrophic soil activity in a 120-yr-old boreal Picea abies forest. We found that at the end of the summer, two months after girdling, the treatment had reduced soil respiration by up to 53%. This figure adds to a growing body of evidence indicating (t-test, d.f. = 7, p < 0.05) that autotrophic respiration may contribute more to total soil respiration in boreal (mean 53 +/- 2%) as compared to temperate forests (mean 44 +/- 3%). Our data also suggests that there is a seasonal hysteresis in the response of total soil respiration to changes in temperature. We propose that this reflects seasonality in the tree below-ground carbon allocation. (C) 2009 Elsevier B.V. All rights reserved.

Nyckelord

Boreal forest; Carbon balance; Soil respiration; Tree-girdling

Publicerad i

Forest Ecology and Management
2009, Volym: 257, nummer: 8, sidor: 1764-1767
Utgivare: ELSEVIER SCIENCE BV

SLU författare

• Högberg, Peter

  • Institutionen för skogens ekologi och skötsel, Sveriges lantbruksuniversitet
    

• Ottosson Löfvenius, Mikaell

  • Institutionen för skogens ekologi och skötsel, Sveriges lantbruksuniversitet
    

• Nordgren, Anders

  • Institutionen för skogsekologi, Sveriges lantbruksuniversitet
    

UKÄ forskningsämne

Miljö- och naturvårdsvetenskap
Förnyelsebar bioenergi


Publikationens identifierare

DOI: https://doi.org/10.1016/j.foreco.2009.01.036

Permanent länk till denna sida (URI)

https://res.slu.se/id/publ/49997