scholarly journals Estimation of water use of Pinus tabulaeformis Carr. in Loess Plateau of Northwest China

2019 ◽  
Vol 67 (3) ◽  
pp. 271-279
Author(s):  
Shengqi Jian ◽  
Zening Wu ◽  
Caihong Hu
Keyword(s):  
Water Use ◽  
Loess Plateau ◽  
Sap Flow ◽  
Northwest China ◽  
Climatic Conditions ◽  
Pinus Tabulaeformis ◽  
Forest Stands ◽  
Sapwood Area ◽  
Stand Transpiration ◽  
The Mean

Abstract Tree transpiration plays a determining role in the water balance of forest stands and in seepage water yields from forested catchments, especially in arid and semiarid regions where climatic conditions are dry with severe water shortage, forestry development is limited by water availability. To clarify the response of water use to climatic conditions, sap flow was monitored by heat pulse velocity method from May to September, 2014, in a 40–year–old Pinus tabulaeformis Carr. plantation forest stands in the semiarid Loess Plateau region of Northwest China. We extrapolated the measurements of water use by individual plants to determine the area–averaged transpiration of the woodlands. The method used for the extrapolation assumes that the transpiration of a tree was proportional to its sapwood area. Stand transpiration was mainly controlled by photosynthetically active radiation and vapor pressure deficit, whereas soil moisture had more influence on monthly change in stand transpiration. The mean sap flow rates for individual P. tabulaeformis trees ranged from 9 to 54 L d−1. During the study period, the mean daily stand transpiration was 1.9 mm day−1 (maximum 2.9 and minimum 0.8 mm day−1) and total stand transpiration from May to September was 294.1 mm, representing 76% of the incoming precipitation over this period. Similar results were found when comparing transpiration estimated with sap flow measurements to the Penman–Monteith method (relative error: 16%), indicating that the scaling procedure can be used to provide reliable estimates of stand transpiration. These results suggested that P. tabulaeformis is highly effective at utilizing scarce water resources in semiarid environments.

scholarly journals Water use pattern of Pinus tabulaeformis in the semiarid region of Loess Plateau, China

2016 ◽  
Vol 25 (3) ◽  
pp. e077 ◽  
Author(s):  
Shengqi Jian ◽  
Xueli Zhang ◽  
Zening Wu ◽  
Caihong Hu
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Water Use ◽  
Loess Plateau ◽  
Sap Flow ◽  
Pinus Tabulaeformis ◽  
Flow Measurements ◽  
Stand Transpiration ◽  
The Mean

Aim of the study: We analyzed the water-use strategy of P. tabulaeformis and determine the relationships between environmental factors and transpiration rates in the P. tabulaeformis woodlands.Area of study: Loess Plateau region of Northwest China.Material and Methods: Sap flow density of the P. tabulaeformis trees was measured with Granier-type sensors. Stand transpiration was extrapolated from the sap flow measurements of individual trees using the following Granier equation.Main results: The mean sap flow rates of individual P. tabulaeformis trees ranged from 9 L day−1 to 54 L day−1. Photosynthetically active radiation and vapor pressure deficit were the dominant driving factors of transpiration when soil water content was sufficient (soil water content>16%), considering that soil water content is the primary factor of influencing transpiration at the driest month of the year. During the entire growing season, the maximum and minimum daily stand transpiration rates were 2.93 and 0.78 mm day−1, respectively. The mean stand transpiration rate was 1.9 mm day−1, and the total stand transpiration from May to September was 294.1 mm.Research highlights: This study can serve as a basis for detailed analyses of the water physiology and growth of P. tabulaeformis plantation trees for the later application of a climate-driven process model.Keywords: Sap flow; stand transpiration; environmental factor; Pinus tabulaeformis; Loess Plateau.

Spatial variability of xylem sap flow in mature beech (Fagus sylvatica) and its diurnal dynamics in relation to microclimate

Botany ◽  
2008 ◽  
Vol 86 (12) ◽  
pp. 1440-1448 ◽  
Author(s):  
An Saveyn ◽  
Kathy Steppe ◽  
Raoul Lemeur
Keyword(s):  
Fagus Sylvatica ◽  
Sap Flow ◽  
Xylem Sap ◽  
Radial Profile ◽  
Vapour Pressure Deficit ◽  
Climatic Conditions ◽  
General Function ◽  
Sap Flux Density ◽  
Sapwood Area ◽  
Diurnal Variability

The spatial and diurnal variability of sap flow in a mature beech tree ( Fagus sylvatica L.) was investigated on days with different climatic conditions (sunny, cloudy, rainy), during the summer. Sap flux density (v) was measured with six heat field deformation probes placed around the stem circumference. Each probe measured v at six sapwood depths. Daily v exhibited clear radial variation, and the shape of the radial profile of v differed substantially among circumferential positions. At some positions, daily v decreased monotonically towards the stem centre, whereas at others it showed an almost monotonic increase. Hence, the conducting sapwood area of the beech was highly asymmetrical. At all positions, conducting sapwood reached beyond the deepest sampled sapwood depth, precluding correct estimations of total sap flow. The radial profile of v also differed among measuring days. A general trend was that the inner sapwood contributed relatively more to total sap flow under better weather conditions. Besides variations among days, the shape of the radial profile of v also showed within-day variations. The contribution of the inner sapwood to total sap flow increased in the afternoon, with increasing vapour pressure deficit and photosynthetic active radiation. Because of large circumferential and temporal variability, no general function for the radial profile of v could be developed.

Stochastic modelling of soil water dynamics and sustainability for three vegetation types on the Chinese Loess Plateau

Soil Research ◽  
2019 ◽  
Vol 57 (5) ◽  
pp. 500 ◽  
Author(s):  
Lizhu Suo ◽  
Mingbin Huang
Keyword(s):  
Stochastic Model ◽  
Soil Water ◽  
Loess Plateau ◽  
Water Dynamics ◽  
Pinus Tabulaeformis ◽  
Soil Conditions ◽  
Vegetation Types ◽  
The Loess Plateau ◽  
Soil Water Dynamics ◽  
The Mean

Soil water dynamics play an active role in ecological and hydrologic processes. Soil water exhibits a stochastic nature because of the large temporal variations in precipitation and evapotranspiration. Objectives of this study were to analyse the probabilistic nature of soil water under three vegetation types, to simulate their probability density functions (PDFs) using a stochastic model, and to determine the most sustainable vegetation types. Soil water data were collected over a 3-year period with a bi-weekly frequency at plots in the Loess Plateau, China, under grass (Bothriochloa ischaemum L., BOI), shrub, sea-buckthorn (Hippophae rhamnoides L., SEB) and tree, Chinese pine (Pinus tabulaeformis Carr, CHP). The data were compared with values simulated using the Laio stochastic model. The results showed that the mean relative soil water contents differed in the order: BOI > CHP > SEB. Soil water was related to the daily rainfall and evapotranspiration. Under the same climate, topography and soil conditions, the soil water PDF was sensitive to a critical water content at which plants begin closing stomata and the mean maximum daily evapotranspiration rate. Based on the shape of the PDFs and their statistical moments, the Laio stochastic model accurately simulated the soil water PDFs under all three vegetation types in the semi-humid area of the Loess Plateau. The soil water PDFs for three vegetation types were simulated with four leaf area index scenarios; BOI and CHP were the most sustainable vegetation types compared with SEB in terms of maintaining soil water availability and soil erosion control.

scholarly journals Radial variations in xylem sap flux in a temperate red pine plantation forest

2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Alanna V. Bodo ◽  
M. Altaf Arain
Keyword(s):  
Flux Density ◽  
Water Use ◽  
Sap Flow ◽  
Xylem Sap ◽  
Red Pine ◽  
Sap Flux ◽  
Plantation Forest ◽  
Sap Flux Density ◽  
Flow Measurements ◽  
Sapwood Area

Abstract Background Scaling sap flux measurements to whole-tree water use or stand-level transpiration is often done using measurements conducted at a single point in the sapwood of the tree and has the potential to cause significant errors. Previous studies have shown that much of this uncertainty is related to (i) measurement of sapwood area and (ii) variations in sap flow at different depths within the tree sapwood. Results This study measured sap flux density at three depth intervals in the sapwood of 88-year-old red pine (Pinus resinosa) trees to more accurately estimate water-use at the tree- and stand-level in a plantation forest near Lake Erie in Southern Ontario, Canada. Results showed that most of the water transport (65%) occurred in the outermost sapwood, while only 26% and 9% of water was transported in the middle and innermost depths of sapwood, respectively. Conclusions These results suggest that failing to consider radial variations in sap flux density within trees can lead to an overestimation of transpiration by as much as 81%, which may cause large uncertainties in water budgets at the ecosystem and catchment scale. This study will help to improve our understanding of water use dynamics and reduce uncertainties in sap flow measurements in the temperate pine forest ecosystems in the Great Lakes region and help in protecting these forests in the face of climate change.

Interannual variation in stand transpiration estimated by sap flow measurement in a semi-arid black locust plantation, Loess Plateau, China

Ecohydrology ◽  
2014 ◽  
Vol 8 (1) ◽  
pp. 137-147 ◽  
Author(s):  
Jian-Guo Zhang ◽  
Jin-Hong Guan ◽  
Wei-Yu Shi ◽  
Norikazu Yamanaka ◽  
Sheng Du
Keyword(s):  
Loess Plateau ◽  
Sap Flow ◽  
Flow Measurement ◽  
Interannual Variation ◽  
Black Locust ◽  
Stand Transpiration ◽  
Semi Arid

Sap flow and water use sources of shelter-belt trees in an arid inland river basin of Northwest China

Ecohydrology ◽  
2015 ◽  
Vol 8 (8) ◽  
pp. 1446-1458 ◽  
Author(s):  
Qin Shen ◽  
Guangyao Gao ◽  
Bojie Fu ◽  
Yihe Lü
Keyword(s):  
River Basin ◽  
Water Use ◽  
Sap Flow ◽  
Northwest China ◽  
Inland River ◽  
Inland River Basin ◽  
Shelter Belt

scholarly journals Dominant controls of transpiration along a hillslope transect inferred from ecohydrological measurements and thermodynamic limits

2016 ◽  
Vol 20 (5) ◽  
pp. 2063-2083 ◽  
Author(s):  
Maik Renner ◽  
Sibylle K. Hassler ◽  
Theresa Blume ◽  
Markus Weiler ◽  
Anke Hildebrandt ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Solar Radiation ◽  
Land Surface ◽  
Sap Flow ◽  
Stand Structure ◽  
Surface Energy Budget ◽  
Turbulent Heat ◽  
Evaporative Demand ◽  
Sapwood Area ◽  
Stand Transpiration

Abstract. We combine ecohydrological observations of sap flow and soil moisture with thermodynamically constrained estimates of atmospheric evaporative demand to infer the dominant controls of forest transpiration in complex terrain. We hypothesize that daily variations in transpiration are dominated by variations in atmospheric demand, while site-specific controls, including limiting soil moisture, act on longer timescales. We test these hypotheses with data of a measurement setup consisting of five sites along a valley cross section in Luxembourg. Both hillslopes are covered by forest dominated by European beech (Fagus sylvatica L.). Two independent measurements are used to estimate stand transpiration: (i) sap flow and (ii) diurnal variations in soil moisture, which were used to estimate the daily root water uptake. Atmospheric evaporative demand is estimated through thermodynamically constrained evaporation, which only requires absorbed solar radiation and temperature as input data without any empirical parameters. Both transpiration estimates are strongly correlated to atmospheric demand at the daily timescale. We find that neither vapor pressure deficit nor wind speed add to the explained variance, supporting the idea that they are dependent variables on land–atmosphere exchange and the surface energy budget. Estimated stand transpiration was in a similar range at the north-facing and the south-facing hillslopes despite the different aspect and the largely different stand composition. We identified an inverse relationship between sap flux density and the site-average sapwood area per tree as estimated by the site forest inventories. This suggests that tree hydraulic adaptation can compensate for heterogeneous conditions. However, during dry summer periods differences in topographic factors and stand structure can cause spatially variable transpiration rates. We conclude that absorption of solar radiation at the surface forms a dominant control for turbulent heat and mass exchange and that vegetation across the hillslope adjusts to this constraint at the tree and stand level. These findings should help to improve the description of land-surface–atmosphere exchange at regional scales.

scholarly journals Radial Growth Response of Picea crassifolia to Climatic Conditions in a Dryland Forest Ecosystem in Northwest China

Forests ◽  
2021 ◽  
Vol 12 (10) ◽  
pp. 1382
Author(s):  
Hanxue Liang ◽  
Shaowei Jiang ◽  
Ali Muhammad ◽  
Jian Kang ◽  
Huoxing Zhu ◽  
...  
Keyword(s):  
Climate Change ◽  
Tree Ring ◽  
Air Temperature ◽  
Radial Growth ◽  
Northwest China ◽  
Climatic Conditions ◽  
Pinus Tabulaeformis ◽  
Future Climate Change ◽  
Picea Crassifolia ◽  
Maximum Air Temperature

As an important barrier against desert invasion in Northwest China, Helan Mountains (HL), Luoshan Mountains (LS) and their natural forests have an extremely important ecological status. It is of great significance to study the relationship between forest growth and climate in this region under the background of global change. At present, relevant research mostly focuses on the Chinese pine (Pinus tabulaeformis Carr.), and little is known about how Qinghai spruce (Picea crassifolia Kom.) responds to climate change. To investigate the potential relationships between radial growth of P. crassifolia and climatic conditions in Ningxia, China, we collected tree-ring samples from P. crassifolia growing in the HL and LS and then established the standard tree-ring width chronologies for the two sites. Correlation analysis together with multivariate linear regression and relative contribution analyses were used, and results showed that radial growth in the HL was determined by the precipitation in the previous September, by the standardized evapotranspiration index (SPEI) in the current March and June, and by the maximum air temperature in the current September. The maximum air temperature in the current September contributed the most (0.348) to the radial growth in the HL. In the LS, radial growth was determined by the precipitation in the previous September and in the current March and by the minimum air temperature in the current July. The factor that made the most contribution was the precipitation in the current March (0.489). Our results suggested that in the wetting and warming future, growth of P. crassifolia in the HL will increase while that in the LS needs further investigation. Our results also provide a basis for predicting how P. crassifolia in northwest China will grow under the background of future climate change and provide a reference for formulating relevant management measures to achieve ecological protection and sustainable development policies.

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