Abstract
The forest vegetation takes up atmospheric carbon dioxide (CO{sub 2}) in photosynthesis. Part of the fixed carbon is released back into the atmosphere during plant respiration but a substantial part is stored as plant biomass, especially in the stems of trees. Carbon also accumulates in the soil as litter and via the roots. CO{sub 2} is released into the atmosphere from these carbon stocks in the decomposition of dead biomass. Carbon balance of a forest stand is the difference between the CO{sub 2} uptake and CO{sub 2} efflux.This study quantifies and analyses the dynamics of carbon balance and component CO{sub 2} fluxes in four Southern Finnish Scots pine stands that covered the typical economic rotation time of 80 years. The study was based on direct flux measurements with chambers and eddy covariance (EC), and modelling of component CO{sub 2} fluxes. The net CO{sub 2} exchange of the stand was partitioned into component fluxes: photosynthesis of trees and ground vegetation, respiration of tree foliage and stems, and CO{sub 2} efflux from the soil. The relationships between the component fluxes and the environmental factors (light, temperature, atmospheric CO{sub 2}, air humidity and soil moisture) were studied with mathematical modelling.The annual CO{sub 2}
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Citation Formats
Kolari, P.
Carbon balance and component CO{sub 2} fluxes in boreal Scots pine stands.
Finland: N. p.,
2010.
Web.
Kolari, P.
Carbon balance and component CO{sub 2} fluxes in boreal Scots pine stands.
Finland.
Kolari, P.
2010.
"Carbon balance and component CO{sub 2} fluxes in boreal Scots pine stands."
Finland.
@misc{etde_1008048,
title = {Carbon balance and component CO{sub 2} fluxes in boreal Scots pine stands}
author = {Kolari, P}
abstractNote = {The forest vegetation takes up atmospheric carbon dioxide (CO{sub 2}) in photosynthesis. Part of the fixed carbon is released back into the atmosphere during plant respiration but a substantial part is stored as plant biomass, especially in the stems of trees. Carbon also accumulates in the soil as litter and via the roots. CO{sub 2} is released into the atmosphere from these carbon stocks in the decomposition of dead biomass. Carbon balance of a forest stand is the difference between the CO{sub 2} uptake and CO{sub 2} efflux.This study quantifies and analyses the dynamics of carbon balance and component CO{sub 2} fluxes in four Southern Finnish Scots pine stands that covered the typical economic rotation time of 80 years. The study was based on direct flux measurements with chambers and eddy covariance (EC), and modelling of component CO{sub 2} fluxes. The net CO{sub 2} exchange of the stand was partitioned into component fluxes: photosynthesis of trees and ground vegetation, respiration of tree foliage and stems, and CO{sub 2} efflux from the soil. The relationships between the component fluxes and the environmental factors (light, temperature, atmospheric CO{sub 2}, air humidity and soil moisture) were studied with mathematical modelling.The annual CO{sub 2} balance varied from a source of about 400 g C/m2 at a recently clearcut site to net CO{sub 2} uptake of 200?300 g C/m2 in a middle-aged (40-year-old) and a mature (75-year-old) stand. A 12-year-old sapling site was at the turning point from source to a sink of CO{sub 2}. In the middle-aged stand, photosynthetic production was dominated by trees. Under closed pine canopies, ground vegetation accounted for 10-20% of stand photosynthesis whereas at the open sites the proportion and also the absolute photosynthesis of ground vegetation was much higher. The aboveground respiration was dominated by tree foliage which accounted for one third of the ecosystem respiration. Rate of wood respiration was in the order of 10% of total ecosystem respiration. CO{sub 2} efflux from the soil dominated the ecosystem respiratory fluxes in all phases of stand development.Instantaneous and delayed responses to the environmental driving factors could predict well within-year variability in photosynthetic production: In the short term and during the growing season photosynthesis follows primarily light while the seasonal variation is more strongly connected to temperature. The temperature relationship of the annual cycle of photosynthesis was found to be almost equal in the southern boreal zone and at the timberline in the northern boreal zone. The respiratory fluxes showed instantaneous and seasonal temperature relationships but they could also be connected to photosynthesis at an annual timescale. (orig.)}
place = {Finland}
year = {2010}
month = {Jul}
}
title = {Carbon balance and component CO{sub 2} fluxes in boreal Scots pine stands}
author = {Kolari, P}
abstractNote = {The forest vegetation takes up atmospheric carbon dioxide (CO{sub 2}) in photosynthesis. Part of the fixed carbon is released back into the atmosphere during plant respiration but a substantial part is stored as plant biomass, especially in the stems of trees. Carbon also accumulates in the soil as litter and via the roots. CO{sub 2} is released into the atmosphere from these carbon stocks in the decomposition of dead biomass. Carbon balance of a forest stand is the difference between the CO{sub 2} uptake and CO{sub 2} efflux.This study quantifies and analyses the dynamics of carbon balance and component CO{sub 2} fluxes in four Southern Finnish Scots pine stands that covered the typical economic rotation time of 80 years. The study was based on direct flux measurements with chambers and eddy covariance (EC), and modelling of component CO{sub 2} fluxes. The net CO{sub 2} exchange of the stand was partitioned into component fluxes: photosynthesis of trees and ground vegetation, respiration of tree foliage and stems, and CO{sub 2} efflux from the soil. The relationships between the component fluxes and the environmental factors (light, temperature, atmospheric CO{sub 2}, air humidity and soil moisture) were studied with mathematical modelling.The annual CO{sub 2} balance varied from a source of about 400 g C/m2 at a recently clearcut site to net CO{sub 2} uptake of 200?300 g C/m2 in a middle-aged (40-year-old) and a mature (75-year-old) stand. A 12-year-old sapling site was at the turning point from source to a sink of CO{sub 2}. In the middle-aged stand, photosynthetic production was dominated by trees. Under closed pine canopies, ground vegetation accounted for 10-20% of stand photosynthesis whereas at the open sites the proportion and also the absolute photosynthesis of ground vegetation was much higher. The aboveground respiration was dominated by tree foliage which accounted for one third of the ecosystem respiration. Rate of wood respiration was in the order of 10% of total ecosystem respiration. CO{sub 2} efflux from the soil dominated the ecosystem respiratory fluxes in all phases of stand development.Instantaneous and delayed responses to the environmental driving factors could predict well within-year variability in photosynthetic production: In the short term and during the growing season photosynthesis follows primarily light while the seasonal variation is more strongly connected to temperature. The temperature relationship of the annual cycle of photosynthesis was found to be almost equal in the southern boreal zone and at the timberline in the northern boreal zone. The respiratory fluxes showed instantaneous and seasonal temperature relationships but they could also be connected to photosynthesis at an annual timescale. (orig.)}
place = {Finland}
year = {2010}
month = {Jul}
}