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Chen S.,Northwest University, China | Chen S.,Qinling National Forest Ecosystem Research Station | Chen C.,Northwest University, China | Zou B.,Oklahoma State University | And 5 more authors.
Shengtai Xuebao/ Acta Ecologica Sinica | Year: 2012

The interception of precipitation by vegetation and subsequent evaporation during and after rain events is an important component of the hydrological budget of forest ecosystems, particularly for forests in ecologically and hydrologically sensitive regions such as Qinling National Forest. This forest was incorporated into the State Natural Forest Protection Project and is managed solely for soil and water conservation. The Qinling Mountains are a major mountain range in China and are the major headwater source for one of the three routes of the South-to-North Water Transfer Project. The evergreen Pinus tabulaeformis is the dominant canopy species at elevations from 1400 to 1700 m. Extensive studies have been conducted to examine the canopy interception, throughfall and stemflow in P. tabulaeformis forest ecosystems across China, mostly in juvenile (≤30 years) or middle-aged (31-50 years) plantations. However, information on rainfall partitioning in natural forests, especially near-mature stands (51-60 years), is lacking, which impedes our understanding of the hydrological ecosystem services in this region. The objective of this study was to understand rainfall partitioning characteristics and lag effects in the Qinling natural secondary P. tabulaeformis forest. Fifty-five-year-old stands of P. tabulaeformis in Ningshan, Shaanxi, were chosen and the precipitation, canopy interception, throughfall and stemflow were measured from 2006 to 2008 (recorded in 5-10 months of each year). One-hundred times complete measurement data were analyzed. Total precipitation was 1576. 4 mm. Rainfall was partitioned as follows: 62. 4% throughfall, 4. 4% stemflow and 33.2% interception by the tree canopy. The redistribution of precipitation by the canopy was more closely related to the rainfall classes. In a single rainfall event, the higher the rainfall class, the greater the stemflow and throughfall rate and the lower the interception rate. The relationships between throughfall (TF), stemflow (SF), crown interception (I) and total rainfall (P) were described significantly by linear, quadratic and power functions, respectively (TF = 0. 6548P -0.4937, R 2 = 0. 9596; SF = -0. 2796 + 0. 0452P + 0. 0005P 2, R 2 = 0. 8179; I = 0. 5958P 08175, R 2 = 0.8064). Under similar rainfall conditions, the higher the rainfall intensity, the shorter the time to saturate the canopy. The timing of throughfall, stemflow and rainfall events after precipitation were not synchronous, and lag periods ranged from (78.5±8.8) min to (16.0±0.0) min and from (111.0 ± 33.0) min to (41.2 ± 0.0) min following precipitation for throughfall and stemflow, respectively. The time lag shortened gradually as rainfall class increased. After precipitation had ceased, especially, when the rainfall is greater than 10.0 mm, the termination of throughfall also lagged from (3.2±2.6) min to (12.0±0.0) min. However, with regard to stemflow prior to termination of rainfall, the smaller the rainfall class, the earlier termination occurred from (-58.3±21.5) min to (-9.8±0.0) min.


Ding X.,Northwest University, China | Zhang S.,Northwest University, China | Zhang S.,Qinling National Forest Ecosystem Research Station | Zhang Y.,Northwest University, China | Zhong W.,Xi'an Jiaotong University
Advanced Materials Research | Year: 2011

Since it lacks theoretical and technological solutions for guiding the eco-transformation of 1st and 2nd generation of development estates (industrial parks) and construction of eco-industrial parks (EIP), the principles for construction and optimization of EIP were put forward through the analyzing of the function and structure of industrial eco-system in EIPs. The 3rd Party Reverse Logistic System (3PRLS) was then introduced to improve the efficiency of materials recycling rate in the operation of EIP. The operation and profit model of 3PRLS were provided, and its information platform was designed for accomplishing the former functions by applying the knowledge of expert system, network topology, and data base. This research introduced the "decomposer" - the 3PRLS to traditional linear industrial system, which is satisfied with market condition as well as technologically feasibility. The technical solution for 3PRLS was also provided. © (2011) Trans Tech Publications Switzerland.


Cui C.,Northwest University, China | Cui C.,Institute of Garden and Flowers | Cai J.,Northwest University, China | Cai J.,Qinling National Forest Ecosystem Research Station | And 2 more authors.
Allelopathy Journal | Year: 2013

The allelopathic effects of walnut rhizosphere soil were investigated by extracting the rhizosphere and adjacent soil beneath walnut trees using 20% methanol, methanol, ethyl acetate and hexane. The effects of extracts were investigated to determine their effects on turnip (Brassica rapa L.) seed germination and seedling growth, the activity levels of superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT), and the malondialdehyde (MDA) content. All extracts inhibited the seed germination, seedling length and root length of turnip than control (soil adjacent to walnut trees). Of the enzymes assayed (SOD, POD, CAT and MDA), The ethyl acetate extract had most inhibitory effects on the activity of POD and MDA, while the methanol extracts were most inhibitory to MDA than control. This indicated that the three enzymes had cooperative effects in elimination of reactive oxygen radicals. We concluded that some compounds present in the rhizosphere soil of walnut trees (from the root exudates) had allelopathic effects on turnip.


Cui C.,Northwest University, China | Cai J.,Northwest University, China | Jiang Z.,Qinling National Forest Ecosystem Research Station | Jiang Z.,Northwest University, China | Zhang S.,Northwest University, China
Allelopathy Journal | Year: 2011

To determine the allelopathic effects of root exudates of walnut trees, the root exudates of 2, 3, and 4-years-old walnut (Juglans regia L.) trees were extracted with the neutral, acidic (pH 3.0), and alkaline (pH 8.0) components of ethyl acetate extract. The bioactivity of these 3-components (neutral, acidic and alkaline) were separately investigated on the seed germination, seedling growth, the activity of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), and the content of malondialdehyde (MDA) of turnip (Brassica rapa L.). The 3-components of ethyl acetate extract of root exudates of walnut trees inhibited the seed germination and seedling growth of turnip as compared to control. Of all the enzymes assayed (SOD, POD, CAT and MDA), the SOD and the POD activity played a cooperative effect in clearing the reactive oxygen radicals. In 3-treatments (neutral, acidic and alkaline) of root exudates of 4-years-old walnut trees, the activities of SOD, POD and CAT enzymes in turnip were higher than the 3-treatments of root exudates of 2 and 3-years-old walnut trees, whereas the acitivity of MDA was lower. Thus in-vitro allelopathic effects of walnut root exudates were more pronounced with the increasing age of walnut trees. The in-vitro inhibitory/stimulatory effects of root exudates of walnut trees varied with the pH of ethyl acetate extract and with the age of walnut trees.


Zhang S.,Northwest University, China | Zhang S.,Qinling National Forest Ecosystem Research Station | Zhang S.,Key Laboratory For Agri Res And Envi Remediation In Loess Plateau Of Agriculture Ministry Of China | Liang C.,Northwest University, China
Environmental Earth Sciences | Year: 2012

This study investigated the effect of a pine/oak forest canopy on rainfall chemistry in the Qinling Mountains. The area is an important water source for China's North-to-South Water Transfer Project. Rainfall and throughfall samples were collected at the Huoditang Natural Forest in 1999, 2004, and 2009. Analyses of the samples indicated that the forest canopy had several important effects on rainfall chemistry. Rainfall pH generally increased as water passed through the canopy. On average, the rainfall pH increased by 0. 54 pH units. The canopy's effect declined after deciduous trees lost their leaves late in the sampling season. Rainfall NO 3 - concentrations generally declined as water passed through the forest canopy, but PO 4 3- concentrations generally increased. On average, rainfall NO 3 - concentration declined by 0. 135 mg/L as it passed though the forest canopy and PO 4 3- increased by 0. 85 mg/L. The forest canopy had a mitigating effect on the base cation content of throughfall. Specifically, K +, Na +, Ca 2+ and Mg 2+ were leached from the canopy when the concentration of these cations in rainfall was low. In contrast, K +, Na +, Ca 2+ and Mg 2+ were absorbed by the canopy when the concentration of these cations in rainfall was high. The pH of rainfall, as well as its K +, Ca 2+ and Mg + concentration, influenced the effect of the forest canopy on the base cation content of throughfall. The concentration of Cd, Pb, and Zn in rainfall generally decreased as water passed through the forest canopy, but the concentration of Fe in rainfall generally increased. The Cd concentration decreased by an average of 3. 938 μg/L, the Pb concentration decreased by an average of 8. 457 μg/L, and the Zn concentration decreased by an average of 0. 986 mg/L. The Fe concentration increased by an average of 0. 009 mg/L. The canopy's ability to absorb Cd declined after several rainfall events in which rainfall Cd concentrations were relatively high. © 2012 Springer-Verlag.


Chen S.,Northwest University, China | Chen S.,Qinling National Forest Ecosystem Research Station | Chen C.,Northwest University, China | Cao T.,Northwest University, China | And 5 more authors.
Shuikexue Jinzhan/Advances in Water Science | Year: 2013

The objective of this study was to understand the effects of rainfall characteristics and micrometeorology on rainfall redistribution within Chinese red pine (or Pinus tabulaeformis) forest. During growing seasons of 2006-2008, gross rainfall, throughfall, stemflow, and micrometeorology were directly observed from a naturally generated secondary coniferous forest in Qinling Mountains, China. Correlation and multiple regression methods were used to examine the relationships among those measured parameters. Results show that the rainfall class is the most important factor in rainfall partitioning. A positive correlation exists between the dependent variable throughfall and each of the following independent variables including rainfall, the interaction terms of rainfall and rainfall duration, and relative humidity. A negative correlation exists between throughfall and the rainfall duration, also between throughfall and temperature. The stemflow was positively correlated with rainfall, interaction terms of rainfall and temperature, negatively correlated with air temperature. There were positive correlations between interception loss and rainfall, rainfall duration, and temperature. There were negative correlations between canopy interception loss and the interaction terms of rainfall with rainfall duration, air temperature. Non-significant correlations were found between throughfall, stemflow, and interception loss with antecedent dry time, wind direction, wind speed, photosynthetic available radiation, and net radiation, respectively.


Li Q.,Northwest University, China | Li Q.,Ningxia University | Cai J.,Northwest University, China | Cai J.,Qinling National Forest Ecosystem Research Station | And 2 more authors.
Allelopathy Journal | Year: 2010

To identify the tolerant understory species of medicinal plants for intercropping with walnut, the allelopathic effects of walnut (Juglans regia L.) leaves leachate (0, 0.25%, 0.5%, 2.5%, 5%) were investigated on the seed germination, seedling growth and physiology of 4 medicinal plants [Isatis tinctoria L., Atractylodes macrocephal Koidz., Polygala tenuifolia Willd. and Salvia miltiorrhiza Bge.]. The aqueous leachate of walnut leaves exerted different allelopathic effects on the test medicinal plants. All aqueous leachate significantly inhibited the seed germination and seedling growth of S. miltiorrhiza., however, lower concentration (0.25%) improved the seed germination and seedlings growth of I. tinctoria., A. macrocephala and P. tenuifolia.. All aqueous leachate had less effects on the fresh weight of P. tenuifolia Willd.. The higher leachate concentration (5%) was inhibitory to all studied parameters. Root length was more sensitive to leachate than shoot length. Among the physiological variables measured, net photosynthesis rate was most sensitive to leachate. The inhibitory/stimulatory effects of walnut leaves leachate differed with receptor plants.


Zhao X.J.,Northwest University, China | Zhang S.L.,Northwest University, China | Zhang S.L.,Qinling National Forest Ecosystem Research Station | Ma G.D.,Northwest University, China
Shengtai Xuebao/ Acta Ecologica Sinica | Year: 2015

hinning intensity is an important factor affecting water quality within a forest ecosystem. However, there has been little research on the effects of forest thinning on water quality. This study investigated the relationship between forest thinning and rainwater chemistry to quantify the effects of thinning intensity on forest water quality. Five experimental field plots with different thinning intensities (0%, 5%, 10%, 15%, and 20%) were established in a natural prunus armandii forest of the Huoditang in Qinling Mountains. Rainwater samples were collected twice a month from June to September in 2012 and 2013. Water chemistry was measured to analyze the chemical effects of tending and thinning intensity on throughfall and litterthrough. Our results showed that thinning intensity had strong relationships with forest water chemistry. Rainwater was slightly acidic, and both the forest canopy and litter layer could reduce the pH value of rainwater, which decreased with increasing thinning intensity. The pH value was 0.48 in throughfall and 0.65 in litterthrough, which was highest in the plot with a thinning intensity of 5%. The concentrations of SO4 2-, NO3 -, and PO4 3- increased as they passed through the forest ecosystem. Both the canopy and litter layers showed strong SO4 2- purification in the plot with 20% thinning intensity. The increases of SO4 2- concentration were statistically significant when compared with NO3 - and PO4 3- concentrations in the control plots, with fewer significant relationships in the plots with higher thinning intensities. The increase of SO4 2- concentration was 4.422 mg/L in throughfall and 1.5 mg/L in litterthrough, compared to the concentration in the thinning plots. A sharp decline in NO3 -, NH+ 4, and PO4 3- concentrations was observed in the 5% thinning plots, compared to concentrations within the control plot, with decreases of 56.3%, 46%, and 9.2% in throughfall and 64.6%, 45%, and 60.8% in litterthrough, respectively. The capability for K+, Ca2+, and Mg2+ leaching in the plots with a thinning intensity of 10% was significantly greater than the leaching capability in the other plots. The increasing fractions of Ca2+and Mg2+ were as high as 89.9% and 120%, respectively, in throughfall, whereas the rising fractions were only 72.4% and 40%, respectively in litterthrough. The increase of K+ was not significant. The rainwater in throughfall and litterthrough contained little Pb2+, Zn2+, and Cd2+ because of the interceptions of different forest layers. The thinning intensity was also strongly related to the changing tendency of heavy metal ions. Compared with the control field plot, the concentrations of Pb2+, Zn2+, and Cd2+were lower than those in the thinning plots. The plots with 20% thinning intensity showed the highest capability for intercepting and aborting heavy metals. The concentrations of Pb2+, Zn2+, and Cd2+ reduced by 10.6%, 22.4%, and 33.5%, respectively. Therefore, the canopy and litter layer in the plot with 20% thinning intensity had the strongest ability to intercept Pb2+, Zn2+, and Cd2+ from rainwater. © 2015, Ecological Society of China. All rights reserved.


Zhao P.,Northwest University, China | Zhao P.,Purdue University | Zhang S.,Northwest University, China | Zhang S.,Qinling National Forest Ecosystem Research Station | Woeste K.,Purdue University
New Forests | Year: 2013

We evaluated eight-year-old seedlings in a black walnut (Juglans nigra L.) progeny test for two quantitative and two qualitative traits. We also used 12 microsatellite markers to genotype the 328 progeny and their maternal parents. Seedling family growth and quality was evaluated based on the progeny test map. These values were compared to family growth and quality after seedlings were genotyped and reassigned to families by parentage assignment software. After genotyping and parentage analysis, about 80 % of the offspring were assigned to the same half-sib family indicated on the planting map. Considerable differences were observed between the ranks of half-sib families based on the planting-map versus the ranks of the families based on the exclusion/assignment of progeny to their family based on genotypes. Analysis of the data without genotypic assignment of progeny to their correct family revealed that the family effect for height was significant, as was family effect for diameter. After seedlings were reassigned to half-sib families based on genotypic information, neither the family effect for height nor the family effect for diameter was significant. The efficiency of the mixed model ANOVA, as measured by Akaike Information Criterion improved by about 30 % after genotyping and exclusion/reassignment of progeny. These results show that genotyping progeny can have a significant effect on the rank of families and potential selection of individuals from a progeny trial, the quality of data analysis, and the efficiency and efficacy of breeding operations. © 2012 Springer Science+Business Media B.V.(outside the USA).


Cai J.,Northwest University, China | Cai J.,Qinling National Forest Ecosystem Research Station | Li S.,Northwest University, China | Zhang H.,Northwest University, China | And 3 more authors.
Plant, Cell and Environment | Year: 2014

Vulnerability curves (VCs) generally can be fitted to the Weibull equation; however, a growing number of VCs appear to be recalcitrant, that is, deviate from a Weibull but seem to fit dual Weibull curves. We hypothesize that dual Weibull curves in Hippophae rhamnoidesL. are due to different vessel diameter classes, inter-vessel hydraulic connections or vessels versus fibre tracheids. We used dye staining techniques, hydraulic measurements and quantitative anatomy measurements to test these hypotheses. The fibres contribute 1.3% of the total stem conductivity, which eliminates the hypothesis that fibre tracheids account for the second Weibull curve. Nevertheless, the staining pattern of vessels and fibre tracheids suggested that fibres might function as a hydraulic bridge between adjacent vessels. We also argue that fibre bridges are safer than vessel-to-vessel pits and put forward the concept as a new paradigm. Hence, we tentatively propose that the first Weibull curve may be accounted by vessels connected to each other directly by pit fields, while the second Weibull curve is associated with vessels that are connected almost exclusively by fibre bridges. Further research is needed to test the concept of fibre bridge safety in species that have recalcitrant or normal Weibull curves. © 2013 John Wiley & Sons Ltd.

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