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Jia J.,Beijing Forestry University | Yu X.,Beijing Forestry University | Li Y.,Shanxi Institute of Forest Inventory and Planning
Journal of Forestry Research | Year: 2015

Continuous recording of precipitation and soil water content (SWC), especially during long periods of torrential rainfall, has proven challenging. Over a 16 h period spanning 21–22 July, 2012, Beijing experienced historic rainfall that totaled 164.4 mm. We used large lysimeter technology in four forested plots to record precipitation and variation in SWC at 10-min intervals to quantify the response of forestland SWC to heavy rainfall in a semi-arid area. Mean, maximum and minimum rainfall intensities were 23.4, 46.8 and 12.0 mm/h, respectively. Rainfall was concentrated in 2–6 mm bursts that accounted for 67.32 % of the total rainfall event. Soil moisture conditions in this region are strongly dependent on patterns of precipitation. Water infiltration into 20, 40, 60, 80, 100, 120 and 160 cm soil layers required 1, 5, 20, 37, 46, 52 and 61 mm of precipitation, respectively, and to fully saturate these soil layers required 80, 120, 140, 150, 180, 200 and 220 mm of precipitation, respectively. © 2015 Northeast Forestry University and Springer-Verlag Berlin Heidelberg Source


Wang Y.,Shanxi University | Wang M.-B.,Shanxi University | Zhu S.-Z.,Shanxi Institute of Forest Inventory and Planning | Zhao T.-L.,Shanxi Institute of Forest Inventory and Planning
Chinese Journal of Ecology | Year: 2015

Forest plays an important role in regional and global carbon cycle. Accurate estimation of biomass and carbon densities of various forest types is important to assess their contributions to total carbon storage in a region. In this study, based on the national forest inventory data in 2005 and 2010, the biomass of main tree species of the forests in the southern Luliang Mountains was estimated by using both the weighted biomass regression model (WBRM) and the continuous function for biomass expansion factor (CFBEF). The results showed that the estimates from the WBRM were significantly higher than those from the CFBEF (P<0.01), and the WBRM was better for biomass estimation at the medium to small scales compared with the CFBEF. On the basis of 28 X 112 (species X plots) carbon density matrix obtained by WBRM, the classification and ordination of forest communities were carried out using the methods of TWINSPAN, DCA and CCA, respectively. Meanwhile, one-way ANOVA was used to test the significance of difference in carbon density among different forest formations, and Pearson correlation analysis was used to assess the correlation of carbon density with the environmental factors (elevation, slope, aspect and position). The results showed that the forest communities in the southern Luliang Mountains were classified into 8 forest formations, and a significant difference in carbon density was found among these formations (P<0.01). Form. Quercus wutaishanica + Acer mono and Form. Q. wutaishanica + Pinus tabuliformis had significantly higher carbon densities than others, and the carbon density of Form. Pinus bungeana + Platycladus orientalis was the lowest among the eight formations. The carbon density in 2010 was significantly higher than that in 2005. The total carbon density increased with an average value of 1.54 t • hm-2 •a-1. The impacts of the environmental factors on the formations were in order of elevation > slope > aspect > position. There were significant correlations between the carbon density and elevation, and slope. The carbon density was first increased with the increase of elevation/slope, and then decreased. The forest carbon density was higher on shady and half-shady slopes (north and east) than on sunny and half-sunny slopes (south and east-south), and was lowest on steep slopes. In addition to tending management, tree species with stronger adaptability to environmental conditions should be selected for reforestation in order to enhance forest carbon density. © 2015, editorial Board of Chinese Journal of Ecology. All rights reserved. Source


Wang Q.-X.,Shanxi University | Wang M.-B.,Shanxi University | Fan X.-H.,Shanxi University | Zhang F.,Shanxi University | And 2 more authors.
Theoretical and Applied Climatology | Year: 2016

The spatial and temporal trends of 11 (7) temperature (precipitation) extreme indices are examined for the Loess Plateau Region (LPR) and its southeast and northwest sub-regions based on daily observations at 214 meteorological stations. Results show widespread significant warming trends for all the temperature extremes except for the diurnal temperature range (DTR) and the lowest daily maximum temperature in each year (TXn) during 1961–2010. When regionally averaged, a significant warming trend is detected for all the indices except for DTR and TXn in the past 50 years. Compared with the entire LPR, a significant warming trend is detected for all the indices except for DTR and TXn over the southeast sub-region of LPR; while it is observed for all the indices over the northwest. The trends for these indices are generally stronger in the northwest than in the southeast in the past 50 years. In contrast, for precipitation indices, only a small percentage of areas show significant drying or wetting trends and, when regionally averaged, none of them displays significant trends during the past 50 years. On the sub-regional scale, however, a larger percentage of areas show significant drying trends for precipitation indices generally over the southeast relative to the entire LPR, and noticeably, the sub-regional average heavy precipitation (R10mm) and wet day precipitation (PRCPTOT) display significant decreasing trends during the past 50 years; whereas only a slightly larger percentage of areas show significant wetting trends for these indices over the northwest compared with the entire LPR, and when sub-regionally averaged, none of the indices have significant trends during the past 50 years. © 2016 Springer-Verlag Wien Source


Meng X.X.,Shanxi University | Di X.Y.,Shanxi University | Wang M.B.,Shanxi University | Zhu S.Z.,Shanxi Institute of Forest Inventory and Planning | Zhao T.L.,Shanxi Institute of Forest Inventory and Planning
Shengtai Xuebao/ Acta Ecologica Sinica | Year: 2013

Chinese pine (Pinus tabulaeformis), an endemic to China, is the most widely distributed conifer in North China. The Qin Mountains are a major east-west mountain range in central China. This range spans about 1500 km from southern Gansu Province in the west to west Henan Province in the east. The highest peak rises to an elevation of 3,767 m above sea level. This range demarcates subtropical and warm temperate zones in China. The Helan Mountains are a mountain range forming the border of Inner Mongolia's Alxa League and Ningxia. It runs in the north-south direction with a length of about 200 km. The highest peak rises to an elevation of 3556 m above sea level. This range demarcates the arid and semi-arid regions in northwest China. To examine whether the mountain barriers have substantial effects on the genetic structure of Chinese pine, the mitochondrial DNA (nad1 and matR introns) sequence characteristics of 10 natural populations of this species from the Qin Mountains, Helan Mountains, and Shanxi and Shaanxi Provinces were studied. The results showed that a total of 27 haplotypes, 172 polymorphic sites, including 35 parsimony informative sites and 137 singleton variable sites were identified from 100 individuals of all 10 Chinese pine populations based on the sequences of two mitotypes. Of all the haplotypes (from h1 to h27), h1 was shared by all the populations; h3, h6, h9 and h27 were shared by 2-5 populations; and 22 other haplotypes were all unique ones. Eight of the 10 populations had one to four unique haplotypes. Although the populations in the north and south sides of the Qin Mountains (i.e. populations ZZ and NS) had one and two unique haplotypes, respectively; and both the populations in east and west sides of Helan Mountains (i.e. populations HLn and HLi) had three unique haplotypes; the average number of the unique haplotypes for them was smaller than that for the populations GD, LY, TY and HL (i.e. the populations in the central distribution area of Chinese pine). A mixed picture of the evolution relationship of the 27 mtDNA haplotypes was found. A close evolution relationship was detected between the unique haplotypes for the populations in the north and south sides of the Qin Mountains or for the populations in east and west sides of the Helan Mountains. There was a close evolution relationship between the unique haplotypes of the populations in the south side of the Qin Mountains or the east side of the Helan Mountains. Some of the unique haplotypes of the Shanxi- shaanxi populations were also detected. In addition, the results revealed that the genetic diversity in the species level was high, and the haplotype diversity and nucleotide diversity were 0.7120 and 0.0050 respectively. The analysis of molecular variance (AMOVA) showed that the percentage of variation within populations (90.16%) was higher than that among populations (9.84%). The genetic differentiation was significant (Fst = 0.0984, P< 0.01) among populations. Despite the mountainous barriers, the populations in the north and south sides of the Qin Mountains and in the east and west sides of the Helan Mountains showed a complicated classification relationship with the Shanxi-shaanxi populations. Therefore it was concluded that the genetic structure of Chinese pine was hardly associated with the mountainous barriers. Source

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