 |
| Titel |
Temporal variability of the NPP-GPP ratio at seasonal and interannual time scales in a temperate beech forest |
| VerfasserIn |
M. Campioli, B. Gielen, M. Göckede, D. Papale, O. Bouriaud, A. Granier |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
1726-4170
|
| Digitales Dokument |
URL |
| Erschienen |
In: Biogeosciences ; 8, no. 9 ; Nr. 8, no. 9 (2011-09-06), S.2481-2492 |
| Datensatznummer |
250006114
|
| Publikation (Nr.) |
 copernicus.org/bg-8-2481-2011.pdf |
|
|
|
|
|
| Zusammenfassung |
The allocation of carbon (C) taken up by the tree canopy for respiration and
production of tree organs with different construction and maintenance costs,
life span and decomposition rate, crucially affects the residence time of C
in forests and their C cycling rate. The carbon-use efficiency, or ratio
between net primary production (NPP) and gross primary production (GPP),
represents a convenient way to analyse the C allocation at the stand level.
In this study, we extend the current knowledge on the NPP-GPP ratio in
forests by assessing the temporal variability of the NPP-GPP ratio at
interannual (for 8 years) and seasonal (for 1 year) scales for a young
temperate beech stand, reporting dynamics for both leaves and woody organs,
in particular stems. NPP was determined with biometric methods/litter
traps, whereas the GPP was estimated via the eddy covariance
micrometeorological technique.
The interannual variability of the proportion of C allocated to leaf NPP,
wood NPP and leaf plus wood NPP (on average 11% yr−1, 29% yr−1 and 39% yr−1,
respectively) was significant among years with up to 12% yr−1 variation in
NPP-GPP ratio. Studies focusing on the comparison of NPP-GPP ratio among
forests and models using fixed allocation schemes should take into account
the possibility of such relevant interannual variability. Multiple linear
regressions indicated that the NPP-GPP ratio of leaves and wood
significantly correlated with environmental conditions. Previous year
drought and air temperature explained about half of the NPP-GPP variability
of leaves and wood, respectively, whereas the NPP-GPP ratio was not
decreased by severe drought, with large NPP-GPP ratio on 2003 due mainly to
low GPP. During the period between early May and mid June, the majority of
GPP was allocated to leaf and stem NPP, whereas these sinks were of little
importance later on. Improved estimation of seasonal GPP and of the
contribution of previous-year reserves to stem growth, as well as reduction
of data uncertainty, will be of relevance to increase the accuracy of the
seasonal assessment of the NPP-GPP ratio in forests. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|