Transpiration, canopy conductance and the decoupling coefficient of a lowland mixed dipterocarp forest in Sarawak, Borneo: dry spell effects

Kumagai, Tomo’omi; Saitoh, Taku M.; Sato, Yoshinobu; Morooka, Toshiyuki; Manfroi, Odair J.; Kuraji, Koichiro; Suzuki, Masatoshi

doi:10.1016/j.jhydrol.2003.10.002

Cited by 150 publications

(108 citation statements)

References 47 publications

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“…R s reflects the physiological control on surface energy exchange of an ecosystem (Costa et al, 2010;Launiainen, 2010;Zhou et al, 2010) and generally increases the Bowen ratio. In this study, R s similarly varied seasonally with plant phenology and showed similar seasonal characteristics to other deciduous forests during the course of the growing season (Cabral et al, 2010;Kutsch et al, 2008;Li et al, 2012). As reported by Tchebakova et al (2002), R s in seasonal droughtstressed periods was much higher than in non-stressed periods.…”

Section: Biophysical Control On Bowen Ratiosupporting

confidence: 79%

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Energy partitioning and surface resistance of a poplar plantation in northern China

et al. 2015

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Abstract. 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 (R s ) normalized by leaf area index (LAI; R s :LAI) increased by 50 % under drought conditions and was the dominant factor controlling the Bowen ratio. Furthermore, R s was the main factor controlling LE during the growing season, even in wet years, as indicated by the decoupling coefficient ( = 0.45 and 0.39 in wet and dry years, respectively). R s was also a major regulator of the LE / LE eq 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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Section: Biophysical Control On Bowen Ratiosupporting

confidence: 79%

“…During midday periods (10:00-15:00 LST), the PenmanMonteith approximation was inverted to calculate the surface resistance (R s ) in Eq. (5) (Kumagai et al, 2004):…”

Section: Biophysical Characteristicsmentioning

confidence: 99%

Energy partitioning and surface resistance of a poplar plantation in northern China

et al. 2015

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“…In this study, the Tr and Gs of the 3 vegetated areas did not exhibit seasonal changes similar to SWC, which is consistent with a majority of studies that have found little or no correlation between SWC and Tr (Fisher et al 2008;Wallace and McJannet 2010). However, this finding differs from the dynamics observed in Acacia mangium stands and in a tropical mixed dipterocarp forest, where Gs was higher in wet than in dry conditions (Kumagai et al 2004). This may be due to the high soil water availability in wetlands, or to the substantial rooting depths that are necessary to provide an adequate water supply during drier periods (Fisher et al 2008).…”

Section: Discussionsupporting

confidence: 90%

Physiological mechanism for the reduction in soil water in poplar (Populus deltoides) plantations in Dongting Lake wetlands

Qin

Xie

et al. 2013

Wetlands Ecol Manage

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The use of large-scale tree plantations has provoked increasing concern regarding the negative effects on local environments in different ecosystems. However, the physiological mechanism underlying the reduction in soil water by tree plantations in wetlands is not clear. The aims of this study were to investigate the effects of poplar (Populus deltoides) plantations on soil water content and to elucidate the underlying physiological mechanisms. To this end, we conducted a 1-year fixed-plot investigation of soil water content (SWC), plant photosynthetic rate (Pn), stomatal conductance (Gs), transpiration rate (Tr), and water-use efficiency (WUE) of individual leaves of 11-and 5-year-old poplars and of reed (Triarrherca sacchariflora, a native herbaceous plant) in the Dongting Lake wetlands, China. SWC was highest in reed, intermediate in 11-year-old poplar, and lowest in 5-year-old poplar, suggesting that poplar plantations produce a lower soil water content in wetlands. From May to July, Pn was significantly higher in reed than in the two poplar stands, but did not differ between the different-aged poplars. As a whole, Gs and Tr were higher, but WUE was lower, in the poplar stands than in reed during the growing season, indicating that Gs and Tr are the key physiological mechanisms associated with the lower soil water in poplar stands. Relationships among Pn, Gs, and Tr showed positive correlations (P \ 0.01) for each type of vegetation. These data suggest that poplar plantations may cause the transformation of wetlands into dry land due to a lower WUE leading to a massive water loss from soil. This, in turn, would have an influence on community composition and ecosystem function after establishment of the plantations.

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“…The control of tree transpiration by the stomata is commonly described by the decoupling factor (Ω), which reflects the extent to which the canopy of trees is coupled to the atmosphere (Kumagai et al, 2004). The coefficient Ω of decoupling ranges between 0 and 1 (Wullschleger et al, 2000;Han et al, 2011).…”

Section: Calculation Of Et and Surface Variablesmentioning

confidence: 99%

Evapotranspiration and control mechanisms in managed Amazonian forest in, Par, Brazil

Aguiar¹,

Oliveira²,

Beldini³

et al. 2017

Afr. J. Agric. Res.

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This work examines whether management causes changes in evapotranspiration (ET) surface conductance (g s ), aerodynamic conductance (g a ) and the decoupling factor (Ω) in managed and natural forest sites in a tropical rain forest in the Amazon. The study was conducted in the Tapajós National Forest (FNT) in managed (logged) and natural (unlogged) forests, which have micrometeorological towers for data capture. For ET estimation, the Penman-Monteith (PM) and Eddy Covariance (EC) equations were used. The models were significantly different only for unlogged ( . Each area has different characteristics for the surface variables, g a , g s and Ω, and therefore the sites were different from each other for the study variables. However, logged ET did not differ for the PM, while EC decreased in the year after the management intervention, and was then followed by an increase.

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Transpiration, canopy conductance and the decoupling coefficient of a lowland mixed dipterocarp forest in Sarawak, Borneo: dry spell effects

Cited by 150 publications

References 47 publications

Energy partitioning and surface resistance of a poplar plantation in northern China

Energy partitioning and surface resistance of a poplar plantation in northern China

Physiological mechanism for the reduction in soil water in poplar (Populus deltoides) plantations in Dongting Lake wetlands

Evapotranspiration and control mechanisms in managed Amazonian forest in, Par, Brazil

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