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| Titel |
Energy partitioning and surface resistance of a poplar plantation in northern China |
| VerfasserIn |
M. Kang, Z. Zhang, A. Noormets, X. Fang, T. Zha, J. Zhou, G. Sun, S. G. McNulty, J. Chen |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1726-4170
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| Digitales Dokument |
URL |
| Erschienen |
In: Biogeosciences ; 12, no. 14 ; Nr. 12, no. 14 (2015-07-21), S.4245-4259 |
| Datensatznummer |
250118027
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| Publikation (Nr.) |
 copernicus.org/bg-12-4245-2015.pdf |
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| Zusammenfassung |
| Poplar (Populus sp.) plantations have been, on the one hand, broadly used in northern China
for urban greening, combating desertification, as well as for paper and wood
production. On the other hand, such plantations have been questioned
occasionally for their possible negative impacts on water availability
due to the higher water-use nature of poplar trees compared with other tree
species in water-limited dryland regions. To further understand the
acclimation of poplar species to semiarid environments and to evaluate the
potential impacts of these plantations on the broader context of the
region's water supply, we examine the variability of bulk resistance
parameters and energy partitioning in a poplar (Populus euramericana cv. "74/76") plantation
located in northern China over a 4-year period, encompassing both dry and
wet conditions. The partitioning of available energy to latent heat flux
(LE) decreased from 0.62 to 0.53 under mediated meteorological drought by
irrigation applications. A concomitant increase in sensible heat flux (H)
resulted in the increase of a Bowen ratio from 0.83 to 1.57. Partial
correlation analysis indicated that surface resistance (Rs) normalized
by leaf area index (LAI; Rs:LAI) increased by 50 % under drought
conditions and was the dominant factor controlling the Bowen ratio.
Furthermore, Rs was the main factor controlling LE during the growing
season, even in wet years, as indicated by the decoupling coefficient
(Ω = 0.45 and 0.39 in wet and dry years, respectively). Rs was
also a major regulator of the LE / LEeq ratio, which decreased from 0.81
in wet years to 0.68 in dry years. All physiological and bioclimatological
metrics indicated that the water demands of the poplar plantation were
greater than the amount available through precipitation, highlighting the
poor match of a water-intensive species like poplar for this water-limited
region. |
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