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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
Front. For. China. 2007, 2 (2): 119-127.
https://doi.org/10.1007/s11461-007-0020-5
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.
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Interspecific relationships in the forest community dominated by Pinus kwangtungensis, an endangered species endemic to China
ZHANG Lu, SU Zhiyao, CHEN Beiguang
Front. For. China. 2007, 2 (2): 128-135.
https://doi.org/10.1007/s11461-007-0021-4
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.
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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
Front. For. China. 2007, 2 (2): 136-142.
https://doi.org/10.1007/s11461-007-0022-3
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.
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Effects of reforestation on the hydrological function of a small watershed in the Three Gorges Reservoir Area
QI Shi, WANG Yunqi, WANG Yujie
Front. For. China. 2007, 2 (2): 148-156.
https://doi.org/10.1007/s11461-007-0024-1
For vegetation communities with hydrological function in the Three Gorges Reservoir Area, the storm event distributed hydrological model Precipitation-Runoff Modeling System (PRMS)-Storm was built based on modular modeling system developed by the US Geological Survey, and was employed to study the effects of forests on peak flows in the Xiangshuixi forest watershed in the Three Gorges Reservoir Area. The results showed that: 1) this simulation study suggested that PRMS-Storm can meet the second level national flood prediction standards of China for simulating storm events of small forest watersheds, and can issue flood forecasting; 2) hydrological functions of different vegetation communities were evaluated, and three simulation scenarios were arranged: mixed conifer-broadleaf forests (scenario 1), broad-leaved forests (scenario 2), and general forests arrangement (scenario 3); 3) the well-arranged forest scenarios can reduce over 20% of surface runoff, result in an increase of over 16% in subsurface flow, and decrease peak flow by 20.8%, 9.6%, and 18.9%, respectively. The reduction of peak flow rates was significant when rainfall peak was higher than 0.8 mm/min, especially for short-term rainfall events. In general, we found that scenarios 1 and 3 were preferable for reducing peak flow rates and volumes in the reforestation practices in the study region, and scenario 1 was better than scenario 3, so the mixed conifer-broadleaf forests had the best hydrological function.
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Effects of forest vegetation on runoff and sediment transport of watershed in Loess area, west China
ZHANG Xiaoming, YU Xinxiao, WU Sihong, LIU Huifang
Front. For. China. 2007, 2 (2): 163-168.
https://doi.org/10.1007/s11461-007-0026-z
This paper aims to study the effects of vegetation on runoff and sediment transport at the watershed scale, and to provide a theoretical basis for afforestation in the Loess area, in the nested Caijiachuan watershed, Jixian County, Shanxi Province of west China. Forest watersheds and farmland watersheds with similar terrain features were selected through cluster analysis to study their runoff and sediment transport characteristics. Results showed that compared with farmland watersheds, runoff generation time in forest watersheds was delayed remarkably, and peak flow was reduced greatly, which indicates that vegetation played an important role in holding and absorbing rainfall. Besides, with the increase of forest coverage, the runoff amount, runoff depth and runoff coefficient decreased during the rainy seasons. The runoff depth and runoff coefficient of farmland watersheds in the rainy season were 5 20-fold as much as that of forest watersheds, and runoff and sediment yield of watersheds with low forest coverage were 2.7 2.9-fold and 3 6-fold as great as those with high coverage during rainstorms, and low forest coverage had larger variation in sediment hydrograph. For the complexity and scale dependence of the influence of forest vegetation on runoff, forest hydrological functions based on regional scale or watershed scale were worthy of further studies.
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Spatial variability of throughfall in a Chinese Pine (Pinus tabulaeformis) plantation in northern China
ZHAN Weiqing, ZHANG Zhiqiang, XIAO Jinqiang, WU Jun
Front. For. China. 2007, 2 (2): 169-173.
https://doi.org/10.1007/s11461-007-0027-y
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.
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Effect of tree-crop intercropping on a young Populus tomentosa plantation
JIANG Yuezhong, QIN Guanghua
Front. For. China. 2007, 2 (2): 174-178.
https://doi.org/10.1007/s11461-007-0028-x
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.
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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
Front. For. China. 2007, 2 (2): 179-184.
https://doi.org/10.1007/s11461-007-0029-9
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.
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Morphological variation of Quercus liaotungensis leaves in Lingkong Mountain, Shanxi Province
LI Mei, HAN Hairong, KANG Fengfeng, MA Qinyan
Front. For. China. 2007, 2 (2): 185-191.
https://doi.org/10.1007/s11461-007-0030-3
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.
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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
Front. For. China. 2007, 2 (2): 192-197.
https://doi.org/10.1007/s11461-007-0031-2
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.
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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
Front. For. China. 2007, 2 (2): 198-203.
https://doi.org/10.1007/s11461-007-0032-1
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.
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AFLP fingerprinting of elite varieties (clones) from the genus Populus
GAO Jianming, ZHANG Yong, WANG Chunguo, CHEN Ruiyang, SONG Wenqin, ZHANG Shougong, QI Liwang
Front. For. China. 2007, 2 (2): 204-209.
https://doi.org/10.1007/s11461-007-0033-0
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.
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Cloning and sequence analysis of gene encoding plasma aquaporin of Tamarix albiflonum
DONG Yuzhi, YANG Chuanping, WANG Yucheng, ZHANG Daoyuan
Front. For. China. 2007, 2 (2): 217-221.
https://doi.org/10.1007/s11461-007-0035-y
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.
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