scholarly journals Severe drought strongly reduces water use and its recovery ability of mature Mongolian Scots pine (Pinus sylvestris var. mongolica Litv.) in a semi-arid sandy environment of northern China

2019 ◽  
Vol 11 (6) ◽  
pp. 880-891 ◽  
Author(s):  
Hongzhong Dang ◽  
Lizhen Zhang ◽  
Wenbin Yang ◽  
Jinchao Feng ◽  
Hui Han ◽  
...  
Keyword(s):  
Pinus Sylvestris ◽  
Water Use ◽  
Scots Pine ◽  
Northern China ◽  
Severe Drought ◽  
Semi Arid

scholarly journals Differences in instantaneous water use efficiency derived from post-carboxylation fractionation respond to the interaction of CO<sub>2</sub> concentrations and water stress in semi-arid areas

2016 ◽  
Author(s):  
Na Zhao ◽  
Ping Meng ◽  
Yabing He ◽  
Xinxiao Yu
Keyword(s):  
Water Stress ◽  
Water Use Efficiency ◽  
Water Use ◽  
Environmental Changes ◽  
Co2 Concentration ◽  
Water Soluble ◽  
Severe Drought ◽  
Arid Areas ◽  
Use Efficiency ◽  
Semi Arid

Abstract. In the context of global warming attributable to the increasing levels of CO2, severe drought can be anticipated in areas with chronic water shortages (semi-arid areas), which necessitates research on the interaction between elevated atmospheric concentrations of CO2 and drought on plant photosynthetic discrimination. As δ13C of water-soluble compounds in leaves was depleted from extracellular CO2 to primary assimilates, no explanation has been offered for 13C fractionation before leaf-exported transportation of photosynthate. Either its variation according to the CO2 concentration and/or water stress gradients, or their interaction have not yet been identified. Therefore, saplings of species typical to a semi-arid area of Northern China that have similar growth status – Platycladus orientalis and Quercus variabilis – were selected and cultivated in growth chambers with orthogonal treatments (four CO2 concentrations [CO2] × five soil volumetric water contents (SWC)). The δ13C of water-soluble compounds extracted from leaves of potted saplings was measured to determine the instantaneous water use efficiency (WUEcp) after cultivation. Instantaneous water use efficiency derived from gas exchange (WUEge) was integrated to estimate differences in δ13C signal variation before leaf-exported translocation of primary assimilates. The WUEge of the two saplings both decreased with increased soil moisture, and increased with elevated [CO2] at 35 %–80 % of Field Capacity (FC) by strengthening photosynthetic capacity and reducing transpiration. Differences in instantaneous water use efficiency (iWUE) according to distinct environmental changes differed between the species. The WUEge of P. orientalis was significantly greater than that of Q. variabilis, while the opposite results were obtained in a comparison of the WUEcp of the two species. The differences between WUEge and WUEcp were clearly species-specific, as demonstrated in the interaction of [CO2] and SWC. Rising [CO2] coupled with moistened soil generated increasing disparities between WUEge and WUEcp in P. orientalis with an amplitude of 0.0328 ‰–0.0472 ‰. Further, the differences between WUEge and WUEcp of Q. variabilis increased as CO2 concentration increased and water stress alleviated (0.0384 ‰–0.0466 ‰). The 13C fractionation in post-photosynthesis was linearly dependent on gs, and was attributed to environmental variation. Thus, cautious descriptions of the magnitude and environmental dependence of apparent post-carboxylation fractionation are worth our attention in photosynthetic fractionation.

scholarly journals Water Use by Chinese Pine Is Less Conservative but More Closely Regulated Than in Mongolian Scots Pine in a Plantation Forest, on Sandy Soil, in a Semi-Arid Climate

2021 ◽  
Vol 12 ◽  
Author(s):  
Hongzhong Dang ◽  
Xueli Zhang ◽  
Hui Han ◽  
Shuai Chen ◽  
Mingyang Li
Keyword(s):  
Soil Water ◽  
Water Use ◽  
Scots Pine ◽  
Xylem Sap ◽  
Soil Layer ◽  
Northern China ◽  
Plantation Forest ◽  
Sap Flux Density ◽  
Chinese Pine ◽  
Dry Conditions

The diversity of plant water use patterns among species and ecosystems is a matter of widespread debate. In this study, Chinese pine (Pinus tabuliformis, CP) and Mongolian Scots pine (Pinus sylvestris var. mongolica, MP), which is co-exist in the shelterbelt plantations in the Horqin Sandyland in northern China, were chosen for comparison of water use traits by monitoring xylem sap flow alongside recordings of the associated environmental factors over four growing seasons. Continuous sap flux density measurements were converted into crown projected area transpiration intensity (Tr) and canopy stomatal conductance (Gs). The results indicated that MP showed a higher canopy transpiration intensity than in CP, with Tr daily means (±standard deviation) of 0.84 ± 0.36 and 0.79 ± 0.43 mm⋅d–1, respectively (p = 0.07). However, the inter-annual variability of daily Tr in MP was not significant, varying only approximately a 1.1-fold (p = 0.29), while inter-annual variation was significant for CP, with 1.24-fold variation (p &lt; 0.01). In particular, the daily mean Tr value for CP was approximately 1.7-times higher than that of MP under favorable soil moisture conditions, with values for relative extractable soil water within the 0–1.0 m soil layer (REW) being above 0.4. However, as the soil dried out, the value of Tr for CP decreased more sharply, falling to only approximately 0.5-times the value for MP when REW fell to &lt; 0.2. The stronger sensitivity of Tr and/or Gs to REW, together with the more sensitive response of Gs to VPD in CP, confirms that CP exhibits less conservation of soil water utilization but features a stronger ability to regulate water use. Compared with MP, CP can better adapt to the dry conditions associated with climate change.

scholarly journals Reconstructed natural runoff helps to quantify the relationship between upstream water use and downstream water scarcity in China's river basins

2019 ◽  
Vol 23 (5) ◽  
pp. 2491-2505 ◽  
Author(s):  
Xinyao Zhou ◽  
Yonghui Yang ◽  
Zhuping Sheng ◽  
Yongqiang Zhang
Keyword(s):  
Surface Water ◽  
Water Resources ◽  
Water Use ◽  
Water Scarcity ◽  
Water Policy ◽  
Socioeconomic Development ◽  
Northern China ◽  
Contribution Analysis ◽  
Decadal Scale ◽  
Semi Arid

Abstract. The increasing conflicts for water resources between upstream and downstream regions appeal to chronological insight across the world. While the negative consequence of downstream water scarcity has been widely analyzed, the quantification of influence of upstream water use on downstream water scarcity has received little attention. Here non-anthropologically intervened runoff (natural runoff) was first reconstructed in upstream, middle stream and downstream regions in China's 12 large basins in the 1970s to 2000s time period using the Fu–Budyko framework, and then compared to the observed data to obtain the developmental trajectories of water scarcity, including the ratio of water use to availability (WTA) and the per capita water availability (FI; Falkenmark Index) on a decadal scale. Furthermore, a contribution analysis was used to investigate the main drivers of water scarcity trajectories in those basins. The results show that China as a whole has experienced a rapid increase of WTA stress with surface water use rapidly increasing from 161 billion cubic meters (12 % of natural runoff) in the 1970s to 256 billion cubic meters (18 %) in the 2000s, with approximately 65 % increase occurring in northern China. In the 2000s, the increase of upstream WTA stress and the decrease of downstream WTA stress occurred simultaneously for semi-arid and arid basins, which was caused by the increasing upstream water use and the consequent decreasing surface water use in downstream regions. The influence of upstream surface water use on downstream water scarcity was less than 10 % in both WTA and FI for humid and semi-humid basins during the study period, but with an average of 26 % in WTA and 32 % in FI for semi-arid and arid basins. The ratio increased from 10 % in the 1970s to 37 % in the 2000s for WTA and from 22 % in the 1980s to 37 % in the 2000s for FI. The contribution analysis shows that the WTA contribution greatly increases in the 2000s mainly in humid and semi-humid basins, while it decreases mainly in semi-arid and arid basins. The trajectories of China's water scarcity are closely related to socioeconomic development and water policy changes, which provide valuable lessons and experiences for global water resources management.

scholarly journals Transpiration of montane Pinus sylvestris L. and Quercus pubescens Willd. forest stands measured with sap flow sensors in NE Spain

2005 ◽  
Vol 9 (5) ◽  
pp. 493-505 ◽  
Author(s):  
R. Poyatos ◽  
P. Llorens ◽  
F. Gallart
Keyword(s):  
Soil Moisture ◽  
Pinus Sylvestris ◽  
Scots Pine ◽  
Sap Flow ◽  
Severe Drought ◽  
Flow Sensors ◽  
Quercus Pubescens ◽  
Area Index ◽  
Sap Flow Sensors ◽  
Ne Spain

Abstract. Stand transpiration was measured during the 2003 and 2004 growing seasons using heat dissipation sap flow sensors in a Scots pine (Pinus sylvestris L.) and a pubescent oak (Quercus pubescens Willd.) forests located in a montane area of the Eastern Pyrenees (NE Spain). The first aim of the study was to assess the differences in quantitative estimates of transpiration (Ec) and the response to evaporative demand of the two stands. Over the studied period of 2003, characterised by a severe drought episode during the summer, the oak stand (Ec was only 110 mm compared to the 239 mm transpired by the Scots pine stand, although the ratio of transpiration to reference evapotranspiration (Ec/ET0) in the oak stand compares well with the expected values predicted for low leaf area index (LAI) oak forests in southern Europe. Scots pine showed a strong reduction in (Ec/ET0 as the drought developed, whereas pubescent oak was less affected by soil moisture deficits in the upper soil. As a second objective, and given the contrasting meteorological conditions between 2003 and 2004 summer periods, the interannual variability of transpiration was studied in the Scots pine plot. Rainfall during the summer months (June-September) in 2003 was almost 40% less than in the same interval in 2004. Accordingly, transpiration was also reduced about 25% in 2003. Finally, Scots pine data from 2003 and 2004 was used to calibrate a simple transpiration model using ET0 and soil moisture deficit (SMD) as input variables, and implicitly including stomatal responses to high vapour pressure deficits (Dd) and soil water status.

scholarly journals Drought-Induced Reductions and Limited Recovery in the Radial Growth, Transpiration, and Canopy Stomatal Conductance of Mongolian Scots Pine (Pinus sylvestris var. mongolica Litv): A Five-Year Observation

Forests ◽  
2019 ◽  
Vol 10 (12) ◽  
pp. 1143 ◽  
Author(s):  
Hongzhong Dang ◽  
Ping Lu ◽  
Wenbin Yang ◽  
Hui Han ◽  
Jun Zhang
Keyword(s):  
Stomatal Conductance ◽  
Pinus Sylvestris ◽  
Scots Pine ◽  
Radial Growth ◽  
Northern China ◽  
Drought Period ◽  
Before And After ◽  
Pine Trees ◽  
Canopy Stomatal Conductance ◽  
Tree Radial Growth

Determining plant–water relationships in response to drought events can provide important information about the adaptation of trees to climate change. The Mongolian Scots pine (Pinus sylvestris var. mongolica Litv), as one of the major tree species to control soil loss and desertification in northern China, has experienced severe degradation in recent decades. Here, we aimed to examine the impacts of a two-year consecutive drought and another year of drought on the radial growth, transpiration, and canopy stomatal conductance of Mongolian Scots pine over a five-year period, especially in terms of its recovery after drought. The study period during 2013–2017 consisted of a ‘normal’ year, a ‘dry year’, a ‘very dry’ year, a ‘wet’ year, and a ‘dry’ year, according to annual precipitation and soil moisture conditions. Based on measurements of the sap flow and diameters at breast height of 11 sample trees as well as the concurrent environmental factors, we quantified the reductions in tree radial growth, transpiration, and canopy stomatal conductance during the drought development as well as their recovery after the drought. The results showed that the tree radial growth, transpiration, and canopy stomatal conductance of Mongolian Scots pines decreased by 33.8%, 51.9%, and 51.5%, respectively, due to the two consecutive years of drought. Moreover, these reductions did not fully recover after the two-year drought was relieved. The minimum difference of these parameters between before and after the two-year consecutive drought period was 8.5% in tree radial growth, 45.1% in transpiration levels, and 42.4% in canopy stomatal conductance. We concluded that the two consecutive years of drought resulted in not only large reductions in tree radial growth and water use, but also their lagged and limited recoveries after drought. The study also highlighted the limited resilience of Mongolian Scots pine trees to prolonged drought in semi-arid sandy environmental conditions.

scholarly journals Transpiration of montane <I>Pinus sylvestris</I> L. and <I>Quercus pubescens</I> Willd. forest stands measured with sap flow sensors in NE Spain

2005 ◽  
Vol 2 (3) ◽  
pp. 1011-1046 ◽  
Author(s):  
R. Poyatos ◽  
P. Llorens ◽  
F. Gallart
Keyword(s):  
Soil Moisture ◽  
Pinus Sylvestris ◽  
Scots Pine ◽  
Sap Flow ◽  
Severe Drought ◽  
Flow Sensors ◽  
Quercus Pubescens ◽  
Area Index ◽  
Sap Flow Sensors ◽  
Ne Spain

Abstract. Stand transpiration was measured during the 2003 and 2004 growing seasons using heat dissipation sap flow sensors in a Scots pine (Pinus sylvestris L.) and a pubescent oak (Quercus pubescens Willd.) forest located in a montane area of the Eastern Pyrenees (NE Spain). The first aim of the study was to assess the differences in quantitative estimates of transpiration (Ec) and the response to evaporative demand of the two stands. Over the studied period of 2003, characterised by a severe drought episode during the summer, the oak stand Ec was only 110mm compared to the 239 mm transpired by the Scots pine stand, although the ratio of transpiration to reference evapotranspiration (Ec/ET0) in the oak stand compares well with the expected values predicted for low leaf area index (LAI) oak forests in southern Europe. Scots pine showed a strong reduction in Ec/ET0 as the drought developed, whereas pubescent oak was less affected by soil moisture deficits in the upper soil. As a second objective, and given the contrasting meteorological conditions between 2003 and 2004 summer periods, the interanual variability of transpiration was studied in the Scots pine plot. Rainfall during the summer months (June-September) in 2003 was almost 40% less than in the same interval in 2004. Accordingly, transpiration was also reduced about 25% in 2003. Finally, Scots pine data from 2003 and 2004 was used to calibrate a simple transpiration model using ET0 and soil moisture deficit (SMD) as input variables, and implicitly including stomatal responses to high vapour pressure deficits (Dδ) and soil water status.

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