Jun 2007, Volume 2 Issue 2
    

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  • Simulation of soil water dynamics in a Caragana intermedia woodland in Huangfuchuan watershed
    JIA Haikun, LIU Yinghui, XU Xia, WANG Kun, GAO Qiong
    2007, 2(2): 119-127. https://doi.org/10.1007/s11461-007-0020-5
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    As vegetation coverage increases, soil water content can decrease due to water uptake and evapotranspiration. At a very high level of plant density, poor growth and even mortality can occur due to the decrease of soil water content. Hence, a better understanding of the relationship between soil water content and the density of plants is important to design effective restoration projects. To study these relationships, we developed a soil water dynamic simulation model of a Caragana intermedia woodland under different slope gradient and slope aspect conditions in the Huangfuchuan watershed on the basis of the previous studies and field experiments. The model took into account the major processes that address the relationships of plants and the environment, including soil characteristics, precipitation, infiltration, vegetation transpiration, and soil evaporation. Daily changes in soil water content, transpiration, and evaporation of the Caragana intermedia woodland with different vegetation coverage, slope gradient, and slope aspect were simulated from 1971 to 2000. Based on the model simulations, we determined the functional relationships among soil water content, plant coverage and slope as well as the optimal plant density on flat slopes. We also determined the effects of slope gradient and slope aspect on soil water content. When slope gradient was less than 10°, the optimal plant density was sensitive to slope gradient. In the slope range from 10° to 30°, plant density was not sensitive to slope gradient. Therefore, it is important to consider planting densities on the hillsides with slope gradients less than 10° for reconstructing vegetation.
  • Interspecific relationships in the forest community dominated by Pinus kwangtungensis, an endangered species endemic to China
    ZHANG Lu, SU Zhiyao, CHEN Beiguang
    2007, 2(2): 128-135. https://doi.org/10.1007/s11461-007-0021-4
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    Interspecific relationships in a natural forest dominated by Pinus kwangtungensis, a rare and endangered pine species endemic to China, were studied based on inventory data from 7,200 m2 plots in Nanling National Nature Reserve. With the aim to quantitatively analyze the relationships of P. kwangtungensis to other species in the forest community and to their habitat, the continuous transect sampling method was employed by placing a horizontal transect (10 m?120 m) at a 100 m altitudinal interval from 1,100 m to 1,600 m a.s.l., which represents the altitudinal range of P. kwangtungensis in Nanling National Nature Reserve. Each transect was further divided into 12 contiguous quadrats (10 m?10 m) for plant censuses. Both canonical correspondence analysis (CCA) and cluster analysis were used to detect the interspecific relationships. The results showed the following: 1) occurrence frequency of P. kwangtungensis in Nanling was ranked Class A in terms of Raunkiaer s law of frequency. P. kwangtungensis dominated in the canopy more than in the subcanopy and understory; 2) both Spearman rank correlation (SRC) coefficients and Pearson correlation coefficients indicated that the number of positive covariation couplets was significantly higher than the negative covariation couplets in the forest community, although SRC appeared to be more sensitive than Pearson correlation analysis. Except for the negative covariation with Litsea elongata, P. kwangtungensis exhibited no significant correlation with other dominant species; 3) altitude, slope, slope aspect, slope shape, thickness of humus layer, and thickness of litter all had significant correlations with the three axes in CCA plot, and the environmental factors in the first two axes defined the ecological conditions of the community. The grouping of the 105 canopy tree species was made according to the characteristics of the species along the first axis. Altitude was the most effective factor influencing the distribution of P. kwangtungensis; 4) variability in spatial distribution among the 105 canopy tree species could be attributed to variations to site environmental factors. The results from CCA and cluster analysis indicated that environmental factors influenced the distribution and ecological characteristics of the plant species in the forest community dominated by P. kwangtungensis.
  • Space-time dynamics of fine root biomass of six forests in the Maoershan forest region, northeast China
    ZHOU Biao, ZHU Shengying, MAO Zijun, WANG Xiuwei, SUN Yuanfa, ZHAO Xizhu
    2007, 2(2): 136-142. https://doi.org/10.1007/s11461-007-0022-3
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    The Maoershan forestry centre is situated in the Zhangguangcai Mountain of the Changbai mountain range. The main forest types in the Maoershan region are plantation (Pinus sylvestris var. mongolica, Pinus koraiensis and Larix gmelinii) and natural secondary forests (Fraxinus mandshurica, Quercus mongolica and Populus davidiana). Fine roots have enormous surface areas, growing and turning over quickly, which plays an important role in terms of substance cycling and energy flow in the forest ecosystem. This study deals with the dynamics of live, dead, and total fine roots ("d5 mm) biomass in the 0 30 cm soil layer using the soil core method. Differences between the six stands in the Maoershan region showed the following results: 1) the fine root biomass in the various stands showed obvious differences. The total fine root biomass of six stands from high to low were F. mandshurica (1,030.0 g/m2)>Q. mongolica (973.4 g/m2)>Pinus koraiensis (780.9 g/m2)>L. gmelinii (718.2 g/m2)>Populus davidiana (709.1 g/m2)>Pinus sylvestris var. mongolica (470.4 g/m2); 2) except for L. gmelinii, the development of live fine root biomass agreed with the trend of total fine root biomass. The maximum biomass of live fine roots in Pinus koraiensis or L. gmelinii stand appeared in May, others in June; in the F. mandshurica stand, the minimum biomass of live fine roots occurred in September, others in July or August; 3) the proportions of dead fine root biomass varied in different stands; 4) the vertical distribution of fine roots was affected by temperature, water, and nutrients; the proportion of fine root biomass was concentrated in the 0 10 cm soil layer. The fine root biomass of six stands in the 0 10 cm soil layer was over 40% of the total fine root biomass; this proportion was 60.3% in F. mandshurica. Space-time dynamics of the various stands had different characteristics. When investigating the substance cycling and energy flows of all forest ecosystems, we should consider the characteristics of different stands in order to improve the precision of our estimates.
  • Impact of forest harvesting on river runoff in the Xiaoxing’an Mountains of China
    CAI Tijiu, TAN Xiaojing
    2007, 2(2): 143-147. https://doi.org/10.1007/s11461-007-0023-2
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    Using the runoff experiment method in a large basin combined with the contrast experiment in a small watershed, and based on the runoff and forest resources data for the past 35 years, this paper studied the serial changes of river runoff in the Xiaoxing an Mountains after forest harvesting. The results showed that the river flow increased in the initial ten years after forest harvesting, but decreased gradually with the growth and crown closure of the Larix gmelini plantations. The river flow tended to be the same or even lower than the level before harvesting. The river runoff had a close correlation with annual rainfall, the size of forest harvesting and regeneration. A significant positive correlation was observed between the annual flow and the size of forest harvesting, which resulted in the increase of river runoff after forest harvesting. Forest harvesting could also significantly increase the peak flood and snowmelt runoff. There was a negative correlation between the regenerated forest area and annual flow, and thus, forest regeneration would decrease annual flow.
  • Hydrological effects of forest litter and soil in the Simianshan Mountains in Chongqing, China
    RAO Liangyi, ZHU Jinzhao
    2007, 2(2): 157-162. https://doi.org/10.1007/s11461-007-0025-0
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    A preliminary study of the hydrological effects of forest litter and soils in the Simianshan Mountains was carried out. Results indicate that the annual accumulation of different forest litters is about 6.80 20.21 t/hm2 and the maximum water carrying capacity ranges from 1.8 to 4.6 mm. Among them the water carrying abilities of the litter of Lithocarpus glabra and natural deciduous forests are larger than that of Pinus massoniana. A power function relationship exists between the accumulated water-carrying volume and time. An investigation of the physical properties shows that forest soils, to a depth of 1 m, have a powerful water-carrying ability, varying from 7.84 to 18.87 mm. Non-linear regression analysis shows that the soil infiltration rate is significantly correlated with time.
  • Spatial variability of throughfall in a Chinese Pine (Pinus tabulaeformis) plantation in northern China
    ZHAN Weiqing, ZHANG Zhiqiang, XIAO Jinqiang, WU Jun
    2007, 2(2): 169-173. https://doi.org/10.1007/s11461-007-0027-y
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    The interception of rainfall by vegetation and the subsequent evaporation of intercepted water from the canopy surface play an important role in hydrological processes, and the water and energy balance of forest ecosystems. Spatial variability of interception has different effects on water yield from watersheds located in different climatic and biome regions. In order to explain the spatial patterns of interception, we adopted grid-sampling method to install rain-gauges to measure throughfall. Results show that the coefficient of variation (Cv) of throughfall tends to decline as rain intensity increases. After the canopy is saturated, Cv of throughfall remained at a constant value, which is close to the Cv of the canopy leaf area index (LAI) value 0.18. Thus, the Cv of LAI is regarded as the extremum of that of throughfall. Because of the special characteristic of Chinese pine (Pinus tabulaeformis), and the lower droopy branches, negative values for interception account for only 13% of the total samples. Furthermore, the max is above 70% of gross rainfall.
  • Effect of tree-crop intercropping on a young Populus tomentosa plantation
    JIANG Yuezhong, QIN Guanghua
    2007, 2(2): 174-178. https://doi.org/10.1007/s11461-007-0028-x
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    In order to study the effect of tree crop intercropping on a young plantation of Populus tomentosa in the plains along the Yellow River, field experiments were conducted by observing the growth of the plantation, the nutrient content in leaves, the nutrient and water content in the soil, and the output of crops. The relationship between forest growth and nutrient content in the tree leaves and the soil were analyzed. Results show that tree crop intercropping in young plantations can not only improve soil water content, but also enhance the contents of organic matter and the available nitrogen, phosphorus and potassium in soil resulting in the vigorous growth of the individual trees. Diameter at breast height (DBH) was positively related to the contents of organic matter in the soil, and the contents of N, P and K in the tree leaves had correlation coefficients of 0.967, 0.955, 0.988 and 0.972, respectively. Whole tree leaf area, crown width, number of branches and the mean length of branches in the intercropped plantation (intercropped with watermelon and vegetables, peanut and winter wheat, and soybean) were, respectively, 1.70 3.0 times, 2.22 2.47 times, 1.0 1.41 times and 1.70 2.32 times of those of CK (without intercropping). Diameter at breast height (DBH) and tree height in the intercropped plantation were 50.5% 136.7% and 27% 59.5% higher than those of the CK, respectively. The study also showed that intercropping with watermelon and vegetables proved to have the highest economic return among the treatments adopted. Tree crop intercropping in young plantations is an effective measure to increase forest growth and economic benefit.
  • Evaluation of the level of threat and protective classification of the vegetation of Makehe Forest in Sanjiangyuan Nature Reserve, west China
    ZOU Dalin, HE Youjun, LIN Qinwen, CUI Guofa
    2007, 2(2): 179-184. https://doi.org/10.1007/s11461-007-0029-9
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    After investigating and studying the vegetation, we have established that Makehe Forest, in Sanjiangyuan Nature Reserve, Qinghai Province, is host to a total of 364 different species, representing 173 genera  in 55 different vegetative families. We propose five quantifiable indices for evaluating the level of threat to these plants: 1) the distribution frequency of the line transect ; 2) the distribution frequency of sample plots; 3) the distribution density inside sample plots; 4) the existing abundance in the forest region; and 5) plant fidelity. The results show that there are two endangered species, six vulnerable species, 12 nearly threatened species and 344 safe species. The study tried to evaluate the urgency for conserving these plants, according to coefficients of closeness to disappearance, of genetic loss and of usefulness. Results also showed that the number of species of primary concern is two; of secondary concern, nine; of the third level, 23; and of least concern, 330 species.
  • Morphological variation of Quercus liaotungensis leaves in Lingkong Mountain, Shanxi Province
    LI Mei, HAN Hairong, KANG Fengfeng, MA Qinyan
    2007, 2(2): 185-191. https://doi.org/10.1007/s11461-007-0030-3
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    In order to study variation of morphological traits and the influencing factors of natural populations of Quercus liaotungensis Koidz. in Lingkong Mountain Nature Reserve of Shanxi region, five populations were included, and 24 morphological traits of leaf and apical bud were investigated. The analysis of variance showed that variation of all the morphological traits within population were significant, whereas significant difference existed in five property indices among populations (α = 0.05), which resulted from genetic and environmental factors. The results revealed that direction and degree of slope, average diameter at breast height in populations, and population density were the main influencing factors. Intrapopulation variation mainly contributed to morphological variation, and the phenotypic differentiation coefficient was 13.31%, which indicated low level of differentiation. But several characteristics exhibited high differentiation level, such as width of the tooth of leaf base (25.99%) and the middle apical bud (25.23%). The morphological indices, including the tooth of leaf base, leaf tip, petiole, and leaf area were precarious and changed a lot within population, which arose from the variation of individual s development. However, only two morphological indices, the middle apical bud and the tooth of leaf base, are unstable, which indicates the extensive influence of environmental factors.
  • Effects of light radiation intensity on photosynthetic characteristics and water use efficiency of Platycladus orientalis and Pinus tabulaeformis seedlings
    ZHANG Weiqiang, HE Kangning, WANG Yunqi, WANG Baitian, DENG Juntao, ZHOU Yi, ZHONG Xijun, LI Zhaoqing
    2007, 2(2): 192-197. https://doi.org/10.1007/s11461-007-0031-2
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    In order to offer a scientific basis for cultivation and management of forests, effects of light radiation intensity on photosynthetic characteristics and water use efficiency of Platycladus orientalis and Pinus tabulaeformis were studied under different soil moisture contents. By adopting artificial control methods to soil moisture, and under simulated photosynthetic radiation (SPR), the net photosynthetic rate (PN), transpiration rate (Tr), water use efficiency (WUE) and intercellular CO2 concentration (Ci) of Platycladus orientalis and Pinus tabulaeformis in the semi-arid region of the Loess Plateau, were studied. Results are as follows: within the photon range of 0 2,200 µmol/(m2 °s), PN, Tr and WUE were enhanced with an increase in SPR in both species. PN and WUE of Platycladus orientalis and Pinus tabulaeformis, however, declined with continued increase in SPR. PN, Tr, WUE and light saturation point (LSP) of Platycladus orientalis were higher than those of Pinus tabulaeformis, while light compensation point (LCP) of Platycladus orientalis was lower than that of Pinus tabulaeformis at the same soil moisture content. The efficiency of light energy utilization of Platycladus orientalis was higher than that of Pinus tabulaeformis; PN, Tr and Ci of Platycladus orientalis and Pinus tabulaeformis were enhanced by increasing soil moisture content, whereas WUE declined. At soil moistures of 7.90%, 13.00% and 19.99%, LSP of Platycladus orientalis was 1,275, 1,450 and 1,675 µmol/(m2 °s) respectively, and LCP was 42, 25 and 13 µmol/(m2 °s) respectively, with corresponding maximal net CO2 photosynthetic rates (Pmax) of 3.04, 4.06 and 5.53 µmol/(m2 °s). At soil moistures of 7.83%, 13.04% and 20.15%, the LSP of Pinus tabulaeformis was 1,100, 1,325 and 1,500 µmol/(m2 °s) respectively, and LCP was 60, 30 and 23 µmol/(m2 °s), with Pmax of 1.08, 3.35 and 4.36 µmol/(m2 °s) respectively.
  • Relationships between xylem embolism and eco-physiological indices in eight woody plants in situ (II): The relationship with photosynthetic eco-physiological indices
    AN Feng, CAI Jing, ZHAO Pingjuan, ZHANG Shuoxin, JIANG Zaimin, ZHANG Yuanying
    2007, 2(2): 198-203. https://doi.org/10.1007/s11461-007-0032-1
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    The relationship between xylem embolism and eco-physiology indices (i.e. photosynthetic available radiation, temperature, relative humidity, photosynthetic rate, transpiration rate, stomatal conductance and water use efficiency) in eight tree species was investigated in situ. The species studied, Robinia pseudoacacia L., Acer truncatum Bge., Hippophae rhamnoides L., Ulmus pumila L., Pinus tabulaeformis Carr., Pinus bungeana Zucc.ex Endl., Ligustrum lucidum Ait., and Salix matsudana Koidz. f. pendula Schneid, grow well on the Xilin campus of Northwest A&F University. Results indicated that photosynthetic available radiation, air temperature and relative humidity can affect xylem embolism by daily adjustment of stomatal conductance, transpiration rate and water relations of a tree. Embolism was a common case in the daily growth of the plants, and there was some correlation between xylem embolism and photosynthetic rate, transpiration rate, stomatal conductance, and water use efficiency. Embolism may thus be an adaptive mechanism by some tree species to water stress.
  • AFLP fingerprinting of elite varieties (clones) from the genus Populus
    GAO Jianming, ZHANG Yong, WANG Chunguo, CHEN Ruiyang, SONG Wenqin, ZHANG Shougong, QI Liwang
    2007, 2(2): 204-209. https://doi.org/10.1007/s11461-007-0033-0
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    Accurate identification of varieties (clones) and knowledge of their genetic relationships are essential for poplar breeding and variety management. In this study, 21 elite poplar varieties of Tacamahaca and Aigeiros in China were fingerprinted using amplified fragment length polymorphism (AFLP) markers. Four AFLP primer pairs developed generated totally 181 AFLP polymorphic fragments, and in particular, each primer pair generated fingerprint profiles specific to each of the tested varieties. The genetic relationships among the varieties were evaluated by dendrograms and multidimensional scaling (MDS). The results showed that the tested poplar can be classified into five groups, and indicated the clear separation of varieties of different sections of poplar and the primary distinction between native and exotic poplar varieties. This study indicated that tested poplar varieties could be identified by their fingerprint profiles and that genetic relationships deduced from the study were consistent with their genealogy. In addition, our results demonstrated that AFLP could be used to construct DNA fingerprints of poplar clones at a large-scale level and to determine genetic relationships of poplar varieties.
  • Cloning and sequence analysis of gene encoding plasma aquaporin of Tamarix albiflonum
    DONG Yuzhi, YANG Chuanping, WANG Yucheng, ZHANG Daoyuan
    2007, 2(2): 217-221. https://doi.org/10.1007/s11461-007-0035-y
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    Plant aquaporins are water-selected-channels in plants and are involved in seed germination, cell elongation, stoma movement, fertilization and so on. Some plant aquaporins also play an important role in drought stress response. In this paper, the gene encoding the Tamarix albiflonum Aquaporin (AQP) was amplified by 5´rapid amplification of cDNA end (RACE) on the basis of the sequence information obtained from the expressed sequence tag of the subtractive hybridization library constructed under PEG6000 stress. The cDNA of the T. albiflonum AQP gene is 1,043 bp long, encoding a protein of 287 amino acids with a predicted molecular mass of 30.9 kDa, has 6 transmembrane regions, and possessing the major intrinsic protein (MIP) family signal consensus sequence SGXHXNPAVT and the higher plant plasma membrane intrinsic protein (PIP) highly conservative sequence GGGANXXXXGY and TGI/TNPARSL /FGAA I/VI/VF/YN. A comparative molecular analysis of the nucleotides equence in National Center for Biotechnology Information (NCBI) databases showed that it shared 95% homology with the gene of Arabidopsis thaliana (MIP-C), with a theoretical isoelectric point 8.84.
  • Effect of different drying methods on liquid penetration of Chinese fir plantation wood
    L? Jianxiong, LIN Zhiyuan, JIANG Jiali, ZHAO Youke, JIANG Jinghui, GAO Ruiqing, YIN Yafang
    2007, 2(2): 222-226. https://doi.org/10.1007/s11461-007-0036-x
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    Chinese fir plantation sapwood and heartwood boards were treated by three drying methods: radio frequency-vacuum drying (RFVD), conventional kiln drying (KD) and high temperature drying (HTD). The maximum amount of dyeing solution uptake by the capillary rising method was used to evaluate the liquid penetration of the treated wood. The pit aspiration ratio was determined by a semithin section method. Changes in wood microstructure were investigated using scanning electron microscopy. The results show that liquid penetration of Chinese fir sapwood after RFVD is significantly higher than that after KD and HTD. Liquid penetration of Chinese fir heartwood after RFVD is higher than that after HTD. Liquid penetration of Chinese fir sapwood is significantly higher than that of heartwood after three drying treatments. Low pit aspiration ratio and cracks of some bordered pits are the main reasons for the increase in liquid penetration after RFVD treatment.
  • Applications of wavelet transformation in the nondestructive test of medium density fiberboard
    WANG Fenghu, ZHU Xiaodong, SUN Jianping
    2007, 2(2): 227-230. https://doi.org/10.1007/s11461-007-0037-9
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    Taking medium density fiberboards (MDF) as samples, the feasibility of the applications of wavelet analysis in a nondestructive test is discussed in this paper. The main results are as follows: the modulus of elasticity of longitudinal resonance, measured by wavelet analysis, can replace the conventional static modulus of elasticity. Their correlation coefficient is significant (p<0.01). The defect of samples can be judged by wavelet analysis, which is superior because it is a nondestructive test.
  • Pyrolytic characteristics of burning residue of fire-retardant wood
    ZHAO Guangjie, REN Qiang, MA Erni, LUO Wensheng, Furuno T
    2007, 2(2): 231-236. https://doi.org/10.1007/s11461-007-0038-8
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    In order to investigate the pyrolytic characteristics of the burning residue of fire-retardant wood, a multifunctional fire-resistance test oven aimed at simulating the course of a fire was used to burn fire-retardant wood and untreated wood. Samples at different distances from the combustion surface were obtained and a thermogravimetric analysis (TG) was applied to test the pyrolytic process of the burning residue in an atmosphere of nitrogen. The results showed that: 1) there was little difference between fire-retardant wood and its residue in the initial temperature of thermal degradation. The initial temperature of thermal degradation of the combustion layer in untreated wood was higher than that in the no burning wood sample; 2) the temperature of the flame retardant in fire-retardant wood was 200 °C in the differential thermogravimetry (DTG). The peak belonging to the flame retardant tended to dissipate during the time of burning; 3) for the burning residue of fire-retardant wood, the peak belonging to hemicellulose near 230 °C in the DTG disappeared and there was a gentle shoulder from 210 to 240 °C; 4) the temperature of the main peaks of the fire-retardant wood and its burning residue in DTG was 100 °C lower than that of the untreated wood and its burning residue. The rate of weight loss also decreased sharply; 5) the residual weight of fire-retardant wood at 600 °C clearly increased compared with that of untreated wood. Residual weight of the burning residue increased markedly as the heating temperature increased when burning; 6) there was a considerable difference with respect to the hermal degradation temperature of the no burning sample and the burning residue between fire-retardant wood and untreated wood.
  • Chemical characteristics of straw fiber and properties of straw fiberboard with different pretreatments
    PAN Mingzhu, LIAN Hailan, ZHOU Dingguo
    2007, 2(2): 237-240. https://doi.org/10.1007/s11461-007-0039-7
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    Surface chemical characteristics of straw fiber have a great effect on the properties of interfacial conglutination between straw fiber and adhesives. In our study, straw was treated by four different methods hot water, acetic acid, sodium sulfite and sodium hydrid sulfite. Our results show that the main chemical group of straw fiber, under the four different treatments, has not changed significantly. The acetic acid treatment reduces pH values of straw fibers and has a significant effect on the internal bonding strength of straw fiberboards. The modulus of rupture and modulus of elasticity did not clearly improve with the four different treatments. The thickness swelling of straw fiberboard treated in different ways is higher than that of standard values. It is concluded that acid treatment is optimal for producing good quality straw fiberboard.