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PubMed | Research Institute of Forestry and China Agricultural University
Type: | Journal: Scientific reports | Year: 2017

The thermal conductivity of dry soils is related closely to air pressure and the contact areas between solid particles. In this study, the thermal conductivity of two-phase soil systems was determined under reduced and increased air pressures. The thermal separation of soil particles, i.e., the characteristic dimension of the pore space (d), was then estimated based on the relationship between soil thermal conductivity and air pressure. Results showed that under both reduced and increased air pressures, d estimations were significantly larger than the geometrical mean separation of solid particles (D), which suggested that conductive heat transfer through solid particles dominated heat transfer in dry soils. The increased air pressure approach gave d values lower than that of the reduced air pressure method. With increasing air pressure, more collisions between gas molecules and solid surface occurred in micro-pores and intra-aggregate pores due to the reduction of mean free path of air molecules. Compared to the reduced air pressure approach, the increased air pressure approach expressed more micro-pore structure attributes in heat transfer. We concluded that measuring thermal conductivity under increased air pressure procedures gave better-quality d values, and improved soil micro-pore structure estimation.


Yue D.,Beijing Forestry University | Wang J.,Chinese Academy of Forestry | Zhou J.,Research Institute of Forestry | Chen X.,Beijing CNNC Institute of Surveying and Mapping Co. | Ren H.,Beijing Forestry University
Mining Science and Technology | Year: 2010

An ILRIS-36D 3-D laser image scanning system was used to monitor the Anjialing strip mine slope on Pingshuo in Shanxi province. The basic working principles, performance indexes, features and data collection and processing methods are illustrated. The point cloud results are analyzed in detail. The rescale range analysis method was used to analyze the deformation characteristics of the slope. The results show that the trend of slope displacement is stable and that the degree of landslide danger is low. This work indicates that 3-D laser image scanning can supply multi-parameter, high precision real time data over long distances. These data can be used to study the distortion of the slope quickly and accurately. © 2010 China University of Mining and Technology.


Tong X.J.,Beijing Forestry University | Zhang J.S.,Research Institute of Forestry | Meng P.,Research Institute of Forestry | Li J.,CAS Beijing Institute of Geographic Sciences and Nature Resources Research
Shengtai Xuebao/ Acta Ecologica Sinica | Year: 2015

Forest plays an important role in carbon cycle and global climate change. To estimate accurately net ecosystem carbon exchange (NEE) between forest ecosystem and the atmosphere and understand the ecophysical factors influencing NEE, it is necessary to study the variation characteristics of CO2 storage flux. In this study, the eddy covariance method and the profile method were used to measure CO2 flux and CO2 concentration over a warm-temperate mixed plantation in the Xiaolangdi area in 2008, respectively. The temporal and spatial variations of CO2 concentration under sunny and cloudy sky conditions above the forest canopy were analyzed. CO2 storage flux obtained by the eddy covariance was compared with those derived from the profile method and the diurnal and seasonal variations of CO2 storage flux were investigated. The results showed that the diurnal and seasonal variations in CO2 concentration were obvious. In the sunny days of the growing season, CO2 concentrations above the plantation canopy decreased continuously and the minimal CO2 concentration appeared at 12:00. After 12:30, CO2 concentration increased slowly. However, in the cloudy days, the maximal and minimal CO2concentrations occurred in the early morning and at about 14:30, respectively. At the annual scale, CO2 concentration peaked in March, with a value of 370 μmol/mol. The minimal CO2 concentration occurred in August, with a value of 347 μmol/mol. CO2 storage flux estimated by the eddy covariance method was 9% lower than that obtained by the profile method. During the growing season of 2008, monthly mean CO2 storage flux was −0.0004 mg CO2 m−2 s−1 and NEE was −0.091 mg CO2 m−2 s−1. At the daily scale, the proportion of CO2 storage flux to NEE was only 0.4%. In 2008, CO2 storage flux and NEE were −46.1 and −1133 g CO2 m−2 a−1, respectively. On an annual scale, CO2 storage flux only accounted for 4.1% of NEE. Therefore, at the longer time (daily or annual) scale, CO2 storage flux could be neglected when NEE is estimated in the mixed plantation of the Xiaolangdi area. © 2015, Ecological Society of China. All rights reserved.


Qirui W.,Henan Academy of Forestry | Jun G.,Research Institute of Forestry
Applied Mechanics and Materials | Year: 2012

Measured the cover soil water content in soil layer 0~30cm of different agroforestry landscape types in Jinghe river with TDR, the landscape types including sloping cropland, apple orchard, apple-clover system, land under forest and grass changed from grain crop and black locust forest. Analyze the distribution characteristic and spatiotemporal variability of the cover soil water. The result showed that the soil water has renewed in a certain extent after a rain period in 1.5 m soil profile; the soil water content is gradually increased from the top of to the bottom of the slope under the affection of the slope location and plant category. The theory model of semivariogram for cover soil water content before rain season and after season, the value of nugget is changed no obviously, and they are 0.25 and 0.30; ranges is 99.7 m and 87.6 m. And the results indicated that soil moisture exhibited high fractal dimensions and clear spatial autocorrelation. The fractal dimensions are 1.71 and 1.74, variogram is main autocorrelation. During rain season the theory semivariogram model is linear, the spatiotemporal variability of soil water content becomes higher with the increase in distance, and its fractal dimension is 1.40. © (2012) Trans Tech Publications, Switzerland.


Huang S.,Chinese Academy of Forestry | Wang B.J.,FPInnovations Wood Products | Lu J.,Chinese Academy of Forestry | Dai C.,FPInnovations Wood Products | And 2 more authors.
BioResources | Year: 2012

Changbai larch (Larix olgensis Henry) is one of the main plantation species in the northern part of China, but so far its utilization has been limited to solid wood, pulping, and paper products. As part of a national initiative, the objective of this work was to develop a good understanding concerning how stand management practices affect larch wood and veneer properties. To cope with the variation of initial and final stand density, the term "relative thinning intensity (RTI)" was introduced to describe the effect of stand thinning on the resulting wood and veneer properties. Nine representative sample trees each from four stands were harvested, then trimmed and bucked. Six 1.25 m long bolts along the entire tree stem were systematically cut to peel 2.6 mm thick veneers. Clear wood specimens were also sawn from matched bolts for mechanical testing for the purpose of comparison and validation. The correlation between the main tree variables and properties of clear wood and veneer was analyzed, and the influence of RTI on key wood and veneer properties was examined and compared. A good correlation was found in density and modulus of elasticity (MOE) between larch clear wood and veneer, giving an R2 of 0.75 and 0.71, respectively. This indicates that veneering can be potentially used to characterize this larch species. The stand with the lowest RTI had the shortest rotation but yielded the best properties of both clear wood and veneer, which highlights the importance of stand management in terms of thinning.


Huang S.,Chinese Academy of Forestry | Wang B.J.,FPInnovations Wood Products | Lu J.,Chinese Academy of Forestry | Lei Y.,Research Institute of Forest Resource Information Techniques | And 2 more authors.
BioResources | Year: 2012

This is the second part of a large research initiative aimed at characterizing Changbai larch (Larix olgensis Henry) for veneer and high-valued product potential. The objective of this work was to investigate the effect of the tree growth characteristics, particularly diameter at breast height (DBH) and radial growth from pith (or peeler core) to bark on clear wood and veneer properties. A population of 36 trees was chosen and classified into three DBH classes, namely 20, 25, and 30 cm, and crosscut into six segments each along the vertical stem. With the entire veneer ribbon peeled from the pith to bark for each segment, the effect of sapwood and heartwood on wood properties was revealed. The tree DBH and height were moderately and positively correlated. The tree DBH significantly affected properties of both clear wood and veneer in a similar pattern. For the larch veneer population, veneer mean ultrasonic propagation time (UPT) and density decreased but veneer mean dynamic modulus of elasticity (MOE) increased from the heartwood to sapwood or from the pith to bark. Among the three DBH classes, the 25 cm DBH yielded the highest mean veneer density and MOE, followed by the 20 cm DBH and 30 cm DBH. This was found to be caused by the radial evolution of veneer properties from the pith to bark in combination with the variation of veneer yield and stem position.


Han L.,Research Institute of Forestry | Gao Y.,North Dakota State University | Li D.,North Dakota State University
PLoS ONE | Year: 2014

Turfgrass nutrient uptake may be differentially affected by different salts. The objective of this study was to compare nutrient uptake in tall fescue (Festuca arundinacea Schreb.) as affected by carbonate, chloride, and sulfate under isoosmotic, iso-Na+ strength conditions. 'Tar Heel II' and 'Wolfpack' cultivars were subjected to NaCl, Na2CO3, Na 2SO4, CaCl2, NaCl+ CaCl2, Na 2CO3+ CaCl2, and Na2 SO4+ CaCl2, in the range of 0 to 225 mM. There was no cultivar difference regarding K, Na, Mg, and Mn content in shoots. 'Tar Heel II' had higher shoot Ca content than 'Wolfpack', which were 6.9 and 5.7 g kg-1, respectively. In general, K+/Na+ ratio decreased with increasing salt concentrations, which reached <1 at about 87.5 mM in Na 2CO3 treatment. All salt treatments decreased Mg content in shoot tissues, especially in Na2CO3 and treatments containing CaCl2. Both Ca and Mg content in shoot were higher in the NaCl treatment than the Na2SO4 and Na2CO 3 treatments. All salt treatments except Na2CO3 had higher Mn content in shoots compared to the control. In conclusion, nutrient uptake was differently affected by carbonate, chloride, and sulfate which are different in pH, electrical conductivity (EC), and osmotic potential at the same concentration. Adding Ca to the sodium salts increased Ca content and balanced K+/Na+ in shoots, but did not increase Mg content, which was below sufficient level. Maintaining Mg content in shoots under salinity stress was recommended. The physiological impact of elevated Mn content in shoot under salinity stress requires further study. © 2014 Han et al.


Rao G.,Research Institute of Forestry | Sui J.,Research Institute of Forestry | Zeng Y.,Chinese Academy of Forestry | Zeng Y.,Research Institute of Forestry | And 6 more authors.
PLoS ONE | Year: 2014

Salix matsudana Koidz. is a deciduous, rapidly growing, and drought resistant tree and is one of the most widely distributed and commonly cultivated willow species in China. Currently little transcriptomic and small RNAomic data are available to reveal the genes involve in the stress resistant in S. matsudana. Here, we report the RNA-seq analysis results of both transcriptome and small RNAome data using Illumina deep sequencing of shoot tips from two willow variants(Salix. matsudana and Salix matsudana Koidz. cultivar 'Tortuosa'). De novo gene assembly was used to generate the consensus transcriptome and small RNAome, which contained 106,403 unique transcripts with an average length of 944 bp and a total length of 100.45 MB, and 166 known miRNAs representing 35 miRNA families. Comparison of transcriptomes and small RNAomes combined with quantitative real-time PCR from the two Salix libraries revealed a total of 292 different expressed genes(DEGs) and 36 different expressed miRNAs (DEMs). Among the DEGs and DEMs, 196 genes and 24 miRNAs were up regulated, 96 genes and 12 miRNA were down regulated in S. matsudana. Functional analysis of DEGs and miRNA targets showed that many genes were involved in stress resistance in S. matsudana. Our global gene expression profiling presents a comprehensive view of the transcriptome and small RNAome which provide valuable information and sequence resources for uncovering the stress response genes in S. matsudana. Moreover the transcriptome and small RNAome data provide a basis for future study of genetic resistance in Salix. © 2014 Rao et al.


Wang L.,Research Institute of Forestry
JAOCS, Journal of the American Oil Chemists' Society | Year: 2012

The potential for using Siberian apricot (Prunus sibirica L.) seed kernel oil as a source of biodiesel raw material is often overlooked when considering Siberian apricots as a greening tree in China. The aim of this research was to study and compare the oil content and fatty acid composition of 17 germplasm accessions in northern regions of China. Oil content ranged from 44.73 to 57.83 % with a mean of 50.18 % for the 17 accessions. In AS-080, AS-013, AS-017 and AS-027, oil contents were higher than 55 %. Percentages of fatty acids varied greatly among different accessions, but all the accessions contained high amounts of important oleic acid. The biodiesel properties of the Siberian apricot seed kernels oil methyl ester were determined and compared to the relevant specifications from the ASTM D6751-2003, EN 14214-2005 and GB/T 20828-2007. In general, germplasm accession PS-80 has been identified as the ideal feedstock for biodiesel production while germplasm accessions PS-17 and PS-27 were found to be the promising feedstock for biodiesel production. © 2012 AOCS.


Li Y.,Research Institute of Forestry | Hui G.,Research Institute of Forestry | Zhao Z.,Research Institute of Forestry | Hu Y.,Research Institute of Forestry
Journal of Vegetation Science | Year: 2012

Aims: Spatial structure is important in describing forest stand structure and change. We present a new method for the quantitative analysis of forest spatial structure based on the relationship of nearest neighbour tree groups. Location: Six hundred m a.s.l., Dongdapo Natural Reserve, Jiaohe, Jilin Province, China Methods: Six plots in three common stand types of natural Korean pine broad-leaved forest in northeast China were used to validate the method. Each plot measured 100 × 100 m, and all trees with DBH ≥5 cm were marked and located using a Total Station. We calculated bivariate distribution of the structural parameters, uniform angle index, mingling and dominance using Winkelmass and Excel software. Results: Most trees in the forest were highly mixed by species and randomly distributed. Individuals with high DBH values were typically surrounded by other species; trees within stochastic distribution patterns were usually surrounded by different species; and medium-sized trees were randomly distributed. Conclusions: The bivariate distribution of structural parameters can provide more direct and useful information about the heterogeneity of spatial structure than can univariate distributions or other conventional stand descriptors. This could be helpful for selective thinning in continuous cover forest management and in modelling and restoring forests. The bivariate distribution of the structural parameters quantifies the two-pair relationships among dominance, uniform angle index and mingling. The quantitative relationships let us further understanding the microenvironments that trees live in and is helpful to precise selection of feller lumber in continue cover forest, and may also aid in modelling and reconstructing forests. © 2012 International Association for Vegetation Science.

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