Two independent estimations of stand-level root respiration on clonal Eucalyptus stands in Congo: up scaling of direct measurements on roots versus the trenched-plot technique.
Root respiration at the level of a forest stand, an important component of ecosystem carbon balance, has been estimated in the past using various methods, most of them being indirect and relying on soil respiration measurements. On a 3-yr-old Eucalyptus stand in Congo-Brazzaville, a method involving the upscaling of direct measurements made on roots in situ, was compared with an independent approach using soil respiration measurements conducted on control and trenched plots (i.e. without living roots). The first estimation was based on the knowledge of root-diameter distribution and on a relationship between root diameter and specific respiration rates. The direct technique involving the upscaling of direct measurements on roots resulted in an estimation of 1.53 micromol m(-2) s(-1), c. 50% higher than the mean estimation obtained with the indirect technique (1.05 micromol m(-2) s(-1)). Monte-Carlo simulations showed that the results carried high uncertainty, but this uncertainty was no higher for the direct method than for the trenched-plot method. The reduction of the uncertainties on upscaled results requires more extensive knowledge of temperature sensitivity and more confidence and precision on the respiration rates and biomasses of fine roots.
Marsden
Claire
C
CIRAD, Persyst, UPR-80 CIRAD, Campus de Baillarguet TA 10/C, 34398 Montpellier cedex 5, France.|UR2PI, BP 1291, Pointe Noire, Congo-Brazzaville.|Current address: Departamento de Ciências Atmosféricas/IAG/Universidade de São Paulo, Rua do Matão, 1226, Cidade Universitária, São Paulo, 05508-900 SP, Brasil.
Nouvellon
Yann
Y
CIRAD, Persyst, UPR-80 CIRAD, Campus de Baillarguet TA 10/C, 34398 Montpellier cedex 5, France.|UR2PI, BP 1291, Pointe Noire, Congo-Brazzaville.
M'Bou
Armel Thongo
AT
UR2PI, BP 1291, Pointe Noire, Congo-Brazzaville.
Saint-Andre
Laurent
L
CIRAD, Persyst, UPR-80 CIRAD, Campus de Baillarguet TA 10/C, 34398 Montpellier cedex 5, France.
Jourdan
Christophe
C
CIRAD, Persyst, UPR-80 CIRAD, Campus de Baillarguet TA 10/C, 34398 Montpellier cedex 5, France.
Kinana
Antoine
A
UR2PI, BP 1291, Pointe Noire, Congo-Brazzaville.
Epron
Daniel
D
UMR INRA UHP 1137 Ecologie et Ecophysiologie Forestière, Université Henri Poincaré Nancy 1, Faculté des Sciences, BP 239, 54506 Vandoeuvre les Nancy cedex, France.
D052818:Autotrophic Processes / Q000502:physiology; D002245:Carbon Dioxide / Q000378:metabolism*; D019069:Cell Respiration / Q000502:physiology; D003223:Congo; D005052:Eucalyptus / Q000033:anatomy & histology / Q000378:metabolism* / Q000382:microbiology; D016468:Forestry / Q000379:methods; D052836:Heterotrophic Processes / Q000502:physiology; D018517:Plant Roots / Q000033:anatomy & histology / Q000378:metabolism* / Q000382:microbiology; D012988:Soil Microbiology
D002245:Carbon Dioxide