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Carbon Dynamics in younger Stands of Pedunculate Oak during two Vegetation Periods

Hrvoje Marjenović orcid.org/0000-0001-5701-7581 ; Hrvatski šumarski institut Jastrebarsko
Maša Zorana Ostrogović orcid.org/0000-0001-9369-0685 ; Hrvatski šumarski institut Jastrebarsko
Giorgio Alberti ; Department of Agricultural and Environmental Sciences, University of Udine, Italy
Ivan Balenović orcid.org/0000-0001-7422-753X ; Hrvatski šumarski institut Jastrebarsko
Elvis Paladić orcid.org/0000-0003-4886-4476 ; Hrvatski šumarski institut Jastrebarsko
Krunoslav Indir orcid.org/0000-0002-8824-1487 ; Hrvatski šumarski institut Jastrebarsko
Alessandro Peressotti ; Department of Agricultural and Environmental Sciences, University of Udine, Italy
Dijana Vuletić orcid.org/0000-0003-4631-7604 ; Hrvatski šumarski institut Jastrebarsko

Sažetak

Net Ecosystem Productivity (NEP) and Net Ecosystem Carbon Balance (NECB) of young Pedunculate oak (Quercus roburL.) stand were investigated. Two independent methods for assessing NEP were used: a) micrometeorological method of Eddy covariance (EC) and, b) combination of biometric method for assessing Net Primary Productivity (NPP) and periodic soil respiration (SR) measurements (named for reasons of brevity the combined method). NEP from combined method was obtained as a difference of NPP and heterotrophic respiration (Rh) which was estimated to have 50% share in the measured total SR.
Maximal measured daily NEP from eddy covariance was 10,7 gC m-2 day-1in 2008., and 12,2 gC m-2day-1in 2009. The annual NEP ranged from 384 gC m-2yr-1in 2008 to584 gC m-2yr-1in 2009 indicating that the stands around the EC tower were actively storing carbon during both years.
From biometric measurements of stem increment using dendrometer bands, height increment and litter production we obtained an average NPP of the stands in the footprint of 777 gC m-2yr-1in 2008 and 846 gC m-2yr-1in 2009. Heterotrophic respiration (Rh) , estimated from SR measurements was 438 gC m-2yr-1in 2008 and 441 gC m-2yr-1in 2009. By subtracting Rhfrom NPP, we obtained NEP of 339 and 405 gC m-2yr-1in 2008 and 2009, respectively.
Comparison of results for NEP during vegetation season reveals that agreement between the two methods was very good until July for both years. Later in the summer and autumn, discrepancy occurs when stem growth ceases but trees continue to actively store carbon. This leads to the underestimation of NEP from combined method during that period, leading to the overall lower values of NEP when compared with NEP values from eddy covariance. There could be several reasons for the discrepancies namely, share of Rhin total SR could be less than 50 %, R:S could be higher than 0.257, or various combinations of both. Further research is needed that would provide better estimates of share of Rhin SR, R:S ratio and soil carbon content.

Ključne riječi

Eddy covariance method; soil respiration; carbon fluxes; carbon sequestration

Hrčak ID:

72315

URI

https://hrcak.srce.hr/72315

Datum izdavanja:

14.10.2011.

Podaci na drugim jezicima: hrvatski

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