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25 April 2021, Volume 57 Issue 4
Linkage between Herbaceous Layer and Overstorey Species along the Pyrogenic Successions in Kanas Taiga Communities
Ke Guo,Cunde Pan,Gebi Yu,Guihua Li,Fan Zhang,Zhuoying Zou,Bo Liu
2021, 57(4):  1-13.  doi:10.11707/j.1001-7488.20210401
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Objective: The aim of this study is to test the linkage between herbaceous layer and overstorey species along the pyrogenic successions in Kanas taiga communities and to reveal its the formation mechanism. Method: Community characteristics, i.e., fire time, fire severity, stand factors and environmental factors, of 369 samples of the identifiable unhuman-disturbed pyrogenic succession communities were investigated in Kanas taiga, Xinjiang, China. Then, the canonical correspondence analysis (CCA) and correlation analysis were performed to analyze the linkage between herbaceous layer and overstorey species. Result: The correlation in the first axis score of CCA between herbaceous layer and overstorey reached a significant level after low-severity fire and moderate-severity fires (P=0.017 < 0.05, P=0.043 < 0.05), but it did not reach a significant level after high-severity fire (P=0.093>0.05). After high-severity fire, the correlation in the first axis score of CCA between herbaceous layer and overstorey reached a significant level in early succession stage (P=0.044 < 0.05), whereas reached a highly significant level in the middle and late succession stages (P=0.008 < 0.01, P=0.006 < 0.01). After moderate-severity fire, the correlation of the first axis score of CCA between herbaceous layer and overstorey reached a significant level in early succession stage (P=0.043 < 0.05), whereas reached a highly significant level in the middle and late succession stages (P=0.006 < 0.01, P=0.004 < 0.01). After the interference of low-intensity fire, there was the highly significant correlation in the first axis score of CCA between herbaceous layer and overstorey across all succession stages (P=0.006 < 0.01, P=0.005 < 0.01, P=0.002 < 0.01). The results of CCA showed that the number of same explanatory variables between herbaceous layer and overstorey (i.e., fire time, fire severity, stand factors and environmental factors) with the significant influences on response variables (i.e., species diversity of herbaceous and canopy layers) were 1, 2 and 4 in early, middle and late succession stages after high-severity fire, respectively. However, after moderate- and low-severity fire, the number of same explanatory variables was 3, 4 and 5 in early, middle and late succession stages, respectively. Conclusion: Our results have demonstrated that after fire disturbance there is a linkage between herbaceous layer and overstorey species during community succession in Taijia forest. The reason may be that species diversity patterns in herbaceous layer and canopy layer have consistent response to same environmental gradient across forest succession. The linkage in species diversity between herbaceous layer and overstorey decreases with the intensity of fire severity, whereas increases along forest succession.

Regulation Effects of Burned Areas Vegetation Restoration on Forest Microclimate Characteristics in the Growing Season
Lihong Wang,Hongkun Gao,Yusen Zhao,Qiang Fu,Chuanyuan He,Xin Sun,Jianxin Liang,Xiaopeng Zhang
2021, 57(4):  14-23.  doi:10.11707/j.1001-7488.20210402
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Objective: This study aims to characterize the changes of air temperature and humidity, and soil temperature in Larix gmelinii plantation in different years of restoration in severely burned areas of Great Xing'an Mountains, and to deepen understanding of the regulating effect of vegetation restoration on microclimate in burned areas. Method: In this study, the method of time-space mutual substitution was adopted to select L. gmelinii plantation in different years of (3-24 years) restoration in severely burned areas of Great Xing'an Mountains. Air temperature and humidity and soil temperature were measured in situ in the growing season from June to September in order to compare the diurnal and seasonal variation of air temperature, relative air humidity and soil temperature of L. gmelinii plantation among different years of restoration. Specifically, air temperature and humidity at 1.5 m above ground were automatically monitored hourly using the temperature-humidity recorder of HOBO Prov2, and soil temperature at 5 cm and 10 cm under ground was automatically monitored hourly using the temperature recorder of WatchDog B101. Result: The diurnal variation of air temperature showed an inverted U-shaped trend, with low values in the morning and evening, and high values during the daytime. The diurnal variation of relative air humidity showed a U-shaped trend, and the diurnal variation of soil temperature showed a sinusoidal curve of different phases. Diurnal variation of soil temperature at 5 cm under ground was higher than that of 10 cm under ground. Maximum and minimum soil temperature at 5 cm under ground occurred earlier than that of 10 cm under ground. Diurnal variation of air temperature was higher than that of soil, and the minimum and maximum air temperature appeared earlier than that of soil for L. gmelinii plantation among different years of restoration. With the increase of years of restoration, the occurrence time of maximum and minimum values of air temperature and humidity and soil temperature all showed a delayed effect, and the diurnal range gradually decreased. After twenty-four years of restoration, the occurrence time of maximum and minimum temperature of air and soil appeared 1-2 h later than that of the control plot, and the occurrence time of maximum and minimum relative air humidity occurred 1-3 h later than that of the control plot. Air temperature in the forest decreased with the increase of years of restoration. After twenty-four years of restoration, air temperatures from June to September were significantly lower than that of the control plot, with decrease of 3.5, 2.96, 3.46 and 3.84 ℃, respectively. In the process of vegetation restoration, relative air humidity from June to September ranged from 58.69% to 85.79%. After twenty-four years of restoration, the relative air humidities from June to September were significantly higher than that in the control plot, with increase of 14.19%, 12.89%, 13.16% and 13.67%, respectively. Soil temperatures at 5 and 10 cm under ground both decreased with the increase of years of restoration. After twenty-four years of restoration, soil temperatures at 5 cm under ground from June to September were 9.71, 6.85, 6.17 and 4.76 ℃ lower than that of the control plot, and soil temperatures at 10 cm under ground were 10.96, 7.82, 7.13 and 5.03 ℃ lower than that of the control plot. Microclimate factors (M) and years of restoration (t) can be fitted by the equation of M=kt+p (k is the regression coefficient of the equation; p is the constant term of the equation) and the goodness of fitting was significant (P < 0.05). Conclusion: During vegetation restoration, temperature of soil and air decreased gradually. However, relative air humidity increased gradually. Forest microclimate is likely to be cloudier, cooler, and wetter with the weakened fluctuations and increased stability.

Effects of Different Regenerated Models on Soil Nitrogen Mineralization in Subtropical Evergreen Broad-Leaved Forest
Yanli Gao,Zhijie Yang,Li Zhang,Decheng Xiong
2021, 57(4):  24-31.  doi:10.11707/j.1001-7488.20210403
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Objective: The purpose of this study was to explore the changes of soil N mineralization after the conversion of subtropical evergreen broad-leaved forest of Castanopsis carlesii to plantation or forest naturally regenerated with artificial enhancement in order to conclude the advantages in N cycling of artificial enhancement of regeneration over the traditional plantation management, therefore to provide a basis for evaluation and selection of forest management models. Method: Natural evergreen forest of Castanopsis carlesii(NF), artificially regenerated secondary forest(AR), and Castanopsis carlesii plantation (CC) in Sanming City, Fujian Province were studied. Soil ammonium nitrogen(NH4+-N), nitrate nitrogen (NO3--N) concentrations, and soil N mineralization rate in the surface layer (0-10 and 10-20 cm) among three forest types were compared. Result: The conversions of NF to AR and CC decreased soil NH4+-N, but increased NO3--N concentration. Compared with NF, the NH4+-N concentration decreased by 5%-13% and 16%-25% in the soil of 0-10 and 10-20 cm respectively, and the NO3--N concentration increased by 1.4%-241% and 68%-871% respectively. The NH4+-N concentration of the AR was 3%-27% higher than that of the CC, and the NO3--N was lower by 40%-65%. Soil net N mineralization rate of the AR and the CC was lower by 11%-12% and 27%-50% after the forest conversion, respectively. The soil net nitrogen mineralization rate of AR was significantly higher than that of CC, and the net nitrification rate was significantly lower than that of CC. Conclusion: Compared to the plantation, the artificial regeneration model caused lower human disturbances on soil leading to a higher return of litter nutrients, a higher soil net nitrogen mineralization rate, and a lower net nitrification rate. This results in a high content of inorganic N and improves soil N availability in AR. Therefore, the model of natural regeneration with artificial enhancement is beneficial to soil nitrogen preservation and improvement of nitrogen availability, also advantageous over plantation management in terms of nitrogen cycling.

Relationship between Patterns of Urban Forest Patches and Their Cooling Effects——A Case Study of Beijing Urban Area
Xiaoting Li,Tong Li,Kuanbiao Qiu,Shasha Jiang,Baoquan Jia
2021, 57(4):  32-42.  doi:10.11707/j.1001-7488.20210404
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Objective: Urban green area has significant cooling effects on urban heat island, however, urban land area for ecological uses is constantly squeezed, and land area available for increasing green land cover is usually very limited. How to mitigate urban heat island through appropriate configuration of landscapes and plant community structure has become the top priority. This study explores the influence of the patterns of forest blocks, landscape configuration and community composition on cooling effect at finer resolution scales in order to provide a basis for the urban planners and natural resource managers. Method: This paper takes the urban area within 1 km beyond the sixth Ring Road of Beijing as the research area. Land surface temperature was retrieved using the 10th band of Landsat-8 TIRS remote sensing image in September of 2013, and world-view-2 remote sensing image with 0.5 m resolution from August to September, 2013 was used to obtain vegetation information. Then, the cooling effect of urban forest was quantified by using the land surface temperature difference between forest patches and the overall urban city. Four landscape indices at patch level, including patch area, perimeter, perimeter area ratio and shape index, and four landscape indices at landscape level, including tree canopy coverage, mean patch size, patch density and aggregation index, were selected to explore the effects of individual characteristics and spatial configuration of urban forest patches on their cooling effect. At the same time, 398 forest patches were selected by stratified random sampling method to investigate their urban forest structure and analyze the relationship between urban forest community structure and cooling effect. Result: Results showed that the mean land surface temperature in Beijing urban area was 29.86 ℃, and impervious surface area was 30.64 ℃. The mean land surface temperature of tree patches over 1 000 m2 was 28.68 ℃, which was 1.18 ℃ lower than that in urban area, and 1.98 ℃ lower than that in impervious surface area. Among the four landscape indices at the patch level, the patch area and perimeter were significantly negatively correlated with the minimum land surface temperature inside the forest patches(R2=0.43, 0.33), while the correlation between perimeter area ratio and shape index and the minimum land surface temperature inside the forest patch was weak, and they were positively correlated (R2=0.25) and negatively correlated (R2=0.10) respectively. There was a nonlinear relationship between patch density and their cooling effect, the minimum land surface temperature increases with the increase of patch density, but it is opposite when the logarithm of patch density reaches -4.85. The aggregation index was positively correlated with the cooling effect of forest patches(R2=0.15). The correlation between community structure index and land surface temperature was weak, the tree height and the proportion of trees in urban forest survey was negatively correlated with land surface temperature of the forest patch, and the Shannon-Wiener index was positively correlated with the land surface temperature of the forest patches(P < 0.05). Conclusion: The forest patches with an area of more than 1 000 m2 in Beijing have significant cooling effects on urban heat island, and the urban tree canopy coverage and forest patch area are the key factors affecting the cooling effect of forest patches. In addition to directly planning large-scale urban forest, priority should be given to planting trees in potential areas close to the existing green areas, in order to increase the existing forest patch areas. At the same time, it is suggested that urban forest development should give priority to the selection of plants with large biomass and appropriate deployment of tree species to improve the cooling capacity of urban green space.

Effects of Salt Stress on Growth and Photosynthetic Characteristics of Magnolia wufengensis Grafted Seedlings
Xiuting Zhao,Yanshuang Wang,Jie Duan,Lüyi Ma,Baohua He,Zhongkui Jia,Ziyang Sang,Zhonglong Zhu
2021, 57(4):  43-53.  doi:10.11707/j.1001-7488.20210405
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Objective: This study investigated the effects of salt stress on the growth and photosynthesis of Magnolia wufengensis grafted seedlings, in order to explore the adaptation mechanism and ability of M. wufengensis under salt stress and provide the basis for the protection and introduction of germplasm resources. Method: A pot experiment was carried out with the M. wufengensis 'Jiaohong Ⅱ' grafted seedlings, and five NaCl gradients (0 (CK), 0.1% (T1), 0.2% (T2), 0.3% (T3) and 0.4% (T4)) were set. After 20 days of the treatment, the growth status, leaf characteristics, gas exchange parameters, chlorophyll fluorescence parameters, and photosynthesis response curve were measured. Result: Salt stress had no significant effect on seedling height relative growth, ground diameter relative growth, stem biomass and root-shoot ratio of M. wufengensis grafted seedlings and had a significant effect on leaf, root biomass and plant dry weight. The leaf biomass, root biomass and dry weight of T1 were higher than CK, while the other salt-treatments were lower than CK. With the increase of salt concentration, the leaf thickness of the grafted seedlings of M. wufengensis was increased first and then decreased, and the leaf thickness of T1 treatment was the largest, reaching 0.30 mm; the dry weight of the leaves was decreased. When the salt concentration was ≥ 0.2%, the content of chlorophyll a, chlorophyll b, total chlorophyll, and the net photosynthetic rate decreased significantly; meanwhile, the value of chlorophyll a/b, stomatal conductance, and transpiration rate decreased significantly under salt stress. Compared with the control, the chlorophyll fluorescence parameters of the M. wufengensis grafted seedlings under salt stress decreased to different degrees. Besides, salt stress significantly reduced the dark respiration rate, light compensation point and light saturation point, and there was no significant difference among those salt treatments. Conclusion: Salt stress significantly affects the growth and photosynthesis of Magnolia wufengensis grafted seedlings, by reducing the photosynthesis activity of leaf cells. In terms of the comprehensive indicators, there is no significant difference in growth and photosynthesis of M. wufengensis grafted seedlings between 0.1% salt stress and the control.

Trade-Off between Twig and Leaf of Pinus koraiensis at Different Life History Stages
Fengjuan Yin,Mingqi Wang,Guangze Jin,Zhili Liu
2021, 57(4):  54-62.  doi:10.11707/j.1001-7488.20210406
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Objective: The relationship between leaf size, twig size and leafing intensity reflects the ability of plant to use spatial resources. Our objective was to reveal the variation and trade-off of leaf and twig traits at different ages of leaf and twig at different life history stages for predicting intraspecific variations and plant survival strategies under different resource conditions. Method: In Liangshui National Nature Reserve of Heilongjiang Province, Pinus koraiensis is the main dominant species of mixed broadleaved-P. koraiensis forest, sample trees of the species at four different life history stages (seedlings, saplings, adult trees and old trees) were selected to measure their cross-sectional area of twig, individual leaf area, total leaf area and volume-based leafing intensity at different ages of leaf and twig. One-way ANOVA was conducted to test significance of the variations in leaf and twig traits among different life history stages and different leaf and twig ages. The method of standardized major axis (SMA) was used to examine the influence of current-year twigs and leaves at different life history stages on the relationships between twig cross-sectional area and individual leaf area, total leaf area, volume-based leafing intensity and between individual leaf area and volume-based leafing intensity, and the influence of leaf and twig ages on the relationships between twig cross-sectional area and total leaf area, volume-based leafing intensity. Result: The twig cross-sectional area and leaf area increased with the gradient of life history stages, while the leafing intensity decreased. There were significant differences in twig and leaf traits among leaf and twig ages. Leaf and twig ages accounted for the most of the variations in leaf and twig traits. Life history stages accounted for 17%, 7% and 3% of the total variation of twig cross-sectional area, total leaf area and individual leaf area. The correlation between current year twig and leaf traits at different life history stages showed heterotrophic growth. At sapling, adult tree and old tree stage, there was a significant positive correlation between the one-year-old twig cross-sectional area and the total leaf area; while there was a negative correlation between the current-year, one-year-old and two-year-old twig cross-sectional area and leafing intensity at old tree stage. Conclusion: At different life history stages of P. koraiensis, the trade-off strategies of the twigs and leaves were different. There was a correlation between the current-year twig and leaf traits at the seedling stage. The twig and leaf traits showed allometric growth at different ages of twigs and leaves.

Effects of Tides on Leaf Phenotypic Modeling and Leaf Economics Spectrum of Kandelia obovata
Beijia Huang,Jing Zhu,Chenyang He,Weihuang Li,Zhiwei Chen,Yue Fan,Tao Hong
2021, 57(4):  63-72.  doi:10.11707/j.1001-7488.20210407
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Objective: The aim of this study was to investigate the responses of leaf phenotype and leaf economics spectrum of Kandelia obovata under natural tidal habitat in order to examine the adaptation mechanism of K. obovata under periodic tidal inundation. Method: The leaves above and under high tide line of mature forest of K. obovata in Luoyuan Bay in Fuzhou City of Fujian Province were measured, with those above the high tide line without tidal inundation used as control group, to study phenotype characteristics of the leaves and the relationships among each leaf characteristics and the leaf economics spectrum. Result: Compared with the leaves above the high tide line, dry weight, petiole length and dry matter content of the leaves under the high tide line were significantly smaller (P < 0.01), the leaf shape index was significantly smaller (P < 0.05) and the specific leaf area was significantly larger (P < 0.01). Among the stomatal characteristics, stomatal length, width, area, circumference, aperture, opening length, opening area and opening circumference of the leaves under the high tide line were significantly larger than those of the leaves above the high tide line(P < 0.01), but the stomatal density was significantly smaller (P < 0.01). Net photosynthetic rate, transpiration rate and stomatal conductance of the leaves under the high tide line were significantly lower, while the CO2 concentration was significantly higher (P < 0.01). Carboxylation rate of the leaves under the high tide line was significantly smaller (P < 0.01), and water use efficiency was not significantly different between the leaves above and under the high tide line. The correlation between the stomatal characteristics and the photosynthetic function of the leaves above the high tide line was higher than that of the leaves under the high tide line, while the correlation between the stomatal characteristics and the foliar morphological traits of the leaves under the high tide line was higher than that of the leaves above the high tide line. Conclusion: Our results demonstrated that the phenotypic difference between the leaves above and under the high tide line was obvious, and the stomatal function of the leaves under the high tide line had strong adaptability, but the photosynthetic function was limited. The stomatal characteristics and the photosynthetical function of the leaves above the high tide line showed synergistic evolution, while the stomatal characteristics and the foliar morphological traits of the leaves under the high tide line indicated adaptive convergence. In order to adapt to the natural tidal habitat, there were obvious survival strategies in the leaves above and under the high tide line of Kandelia obovata. The results of the leaf economics spectrum indicated that the leaves under the high tide line generally shifted toward the "slow investment-return" end, with smaller dry matter content and stomatal density, lower net photosynthetic rate and larger specific leaf area, stomatal area and stomatal opening, so as to adapt to the extreme tidal inundation environment of low light and hypoxia. The leaves above the high tide line shifted toward the "fast investment-return" end to cope with special habitats such as strong winds and waves.

Effects of Hormones and Nutrients on the Directional Growth of Lateral Rhizome Bud of Indocalamus decorus
Rui Gu,Sen Xu,Shuanglin Chen,Ziwu Guo,Chao Zhang
2021, 57(4):  73-81.  doi:10.11707/j.1001-7488.20210408
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Objective: Dwarf bamboo is widely used in landscaping. Its propagation in container by rhizome is an important means for dwarf bamboo production for all year round afforestation and fast landscaping. The quality of the bamboo saplings is closely associated with the sprouting of the lateral buds of rhizome. In this study, rhizome segments of Indocalamus decorus were propagated in containers to characterize the sprouting of the lateral buds of rhizome and to reveal the synergistic effect of endogenous hormones and nutrients on the sprouting of the lateral buds. The study is intended to provide a basis for high-quality and efficient cultivation of dwarf bamboo saplings. Method: One-year-old rhizome segments of I. decorus with two diameter grades (smaller rhizomes (D1, 2.90 mm ±0.32 mm) and bigger rhizome (D2, 5.42 mm±0.63 mm)) and three length classes (L1, 3 cm; L2, 6 cm; L3, 9 cm) were used in an experiment with a total of 6 treatments. The number, ground diameter and height of young bamboos which grew from rhizome lateral buds were investigated, and the contents of IAA, GA, ABA, CTK, C, N, P of the rhizomes during the periods of rhizome planting, lateral bud sprouting and new bamboo growing were measured. Result: Lateral buds at both segment ends in each treatment sprouted in a much higher proportion, reaching 85.15%-98.04%, significantly higher than those in the middle part (24.36%-37.58%), it showed that more lateral buds sprouted apically or basally. There was no significant difference in the growth status of young bamboos (number, ground diameter and height) among different rhizome segment positions. Meanwhile, there were also no significant changes in the hormones and nutrients of the rhizome during the periods of rhizome planting and new bamboo growing. However, GA, N, P content and GA/ABA, CTK/ABA, (IAA+GA+CTK)/ABA, N/P contents were significantly higher in the proximal and distal part than in the middle part, while ABA content and C/N, C/P contents were opposite, and IAA, CTK, C contents were not significantly different between different rhizome segment parts during the period of lateral bud sprouting. It showed that hormones play a decisive role in the sprouting position of lateral buds in the rhizome segment, while the nutrient content may control the number of sprouting lateral buds. Conclusion: There was a clear positional bias in the sprouting of lateral rhizome buds of Indocalamus decorus, which was mainly affected by the joint regulation of endogenous hormones and nutrients of the rhizome segment during lateral bud sprouting period. The rhizome segment could regulate the growth of lateral buds through nutrient stoichiometry and hormone balance.

Establishment of A Transient Transformation System for Stem Segments of Poplar 84K
Xiaojun Li,Yi An,Lichao Huang,Wei Zeng,Mengzhu Lu
2021, 57(4):  82-89.  doi:10.11707/j.1001-7488.20210409
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Objective: A large scale of plantation are needed to meet the demand for timber in China and the wood quality of fast-growth plantations needs to be improved. The study of gene regulation of wood formation is the basis for improvement of wood quality. In order to reveal the molecular mechanisms on the wood development, it is particularly important to establish a fast, convenient and efficient transient transformation system. Method: Microsections were used to observe the cambium activity of the 1-year-old poplar (Populus alba×P. glandulosa '84K') dormancy-released stems under hydroponic culture as a transient transformation receptor. The enhanced green fluorescent protein (eYGFP) was used as a reporter gene to be constructed in an expression vector. The Agrobacterium-mediated vacuum infiltration method was used for transient transformations. The L9(34) orthogonal test was used to optimize the Agrobacterium GV3101 infiltration concentration, vacuum infiltration transformation time, vacuum infiltration transformation frequency and culture time after transformation. Result: The dormancy of annual shoots was released under water culture at room temperature. The cambium had been active in water for 15 days, and new vessels had appeared. Abundant xylem cells accumulated in about 30 days. It showed that the stems could go through the whole process of wood formation, such as the differentiation of cambium and the formation of xylem within one month. From the morphological, development processes of cambium, xylem and phloem were not different from those of normal trees. Using Agrobacterium-mediated vacuum infiltration method, green fluorescence observation under excitation light in the stem slice indicated the transformation result of the stem. Through orthogonal test analysis, the influence of the four conditions was ranked as follows: culture time > vacuum infiltration transformation time > Agrobacterium concentration > vacuum infiltration transformation frequency. The optimal combination is that the Agrobacterium concentration (OD600) is 0.9, vacuum infiltration transformation time is 20 min, vacuum infiltration transformation frequency is 2, and culture 15 days after transformation. Conclusion: The Agrobacterium-mediated vacuum infiltration transient transformation system of poplar '84K' stem segments was established. This system can be used to identify the functions of genes involved in vascular tissue differentiation in a short time, which is helpful for the study of the regulation mechanism of xylem development. This method also provides a basis for the study of related genes in other woody plants.

Inversion of Forest Leaf Area Index Based on PROSAIL Model and Multi-Angle Remote Sensing Data
Ying Pan,Mingming Ding,Jie Lin,Qiao Dai,Geng Guo,Linlin Cui
2021, 57(4):  90-106.  doi:10.11707/j.1001-7488.20210410
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Objective: The aim of this study was to improve the inversion accuracy of vegetation LAI (leaf area index) on the regional scale based on multi-angle PROBA/CHRIS remote sensing data and field measured data, and provide a new method and model for regional soil erosion remote sensing quantitative monitoring. Method: In this study, Mount Zijin and Mount Mufu in Nanjing were selected as the study areas. Through the methods of field experiments, remote sensing image, radiation transfer model and mathematical models, this study established the LAI inversion model of random forest model based on PROSPECT+SAIL (scattering by arbitrarily inclined leaves) model—PROSAIL model and multi-angle PROBA/CHRIS (project for on-board autonomy/compact high resolution imaging spectrometer) remote sensing data. The sensitivity analysis and applicability evaluation of PROSAIL model were carried out, and the optimal LAI inversion model was also determined. The accuracies were verified and evaluated by the ground measured LAI values. Result: The sensitivity of input parameters of the PROSAIL model was LAI>Cab (chlorophyll a and b content)>Cm (leaf dry matter content)>SL (hotspot parameters)>N (blade internal structure parameters)>Cw (equivalent water thickness). The accuracy of the canopy reflectance simulated by the PROSAIL model was 0°> 36°>-36°>55°>-55°. In the single angle LAI inversion models, the accuracy of forward observation angle 55° was the highest, and the R2 (coefficient of determination), RMSE(root mean square error) and MAPE(mean absolute percentage error) were 0.915 7, 0.235 7 and 0.042 6, respectively. Compared with the traditional vertical observation, the R2 of the 55° model increased by 0.75%, and the RMSE and MAPE decreased by 3.76% and 5.12%, respectively. Compared with the nonlinear regression model, the R2 of the 55° model increased by 0.7%, and the RMSE and MAPE decreased by 15.40% and 11.98%, respectively. The accuracy of single angle inversion models was 55°>36°>0°>-55°>-36°. In the LAI inversion models based on the multi-angle data, the three angles combination of 0°, 36° and 55° had the highest accuracy with the R2, RMSE and MAPE of 0.918 4, 0.231 9 and 0.041 5, respectively. Compared with single angle 55°, the R2 of the three angles combination model increased by 0.29%, and the RMSE and MAPE decreased by 1.61% and 2.58%, respectively. Compared with the traditional vertical observation, the R2 of the three angles combination model increased by 1.05%, and the RMSE and MAPE decreased by 5.31% and 7.57%, respectively. Compared with the nonlinear regression model, the R2 of the three angle combination model increased by 0.79%, and the RMSE and MAPE increased by 6.72% and 9.19%, respectively. The LAI in the western region of Mount Zijin was between 0.44 and 6.70, and the average LAI of forest was 3.04. The spatial distribution pattern of LAI in the western woodland of Mount Zijin showed "high in the north and south and low in the middle" as a whole. Conclusion: The optimal LAI inversion model was the random forest LAI inversion model based on three angles combination (0°, 36°, 55°). On the one hand, increasing the observation angle can provide more information about vegetation crown structure, and the inversion accuracy of LAI will increase with the increase of observation angle. However, on the other hand, too many observation angles will lead to more uncertainty in pixel space resampling, leaf shadow, soil shadow and so on, and the accuracy of LAI inversion will decrease. No matter single angle and multi-angle data, the accuracy of random forest LAI inversion model was higher than that of nonlinear regression model, which indicated that the random forest model can obviously improve the inversion accuracy of LAI and was suitable for the inversion of LAI on the regional scale. Multi-angle remote sensing data can reflect the three-dimensional structure information of vegetation and the characteristics of multi-dimensional spatial structure of ground objects, and significantly improve the low accuracy of LAI inversion by traditional vertical observation, thus effectively improve the inversion accuracy of vegetation LAI.

Phenotypic and Virulence Gene Expression Difference of Esteya vermicola, A Biocontrol Fungus for Pine Wood Nematode under Carbon and Nitrogen Conditions
Ran He,Ruizhen Wang,Yue Ying,Liangjian Qu,Yong'an Zhang
2021, 57(4):  107-115.  doi:10.11707/j.1001-7488.20210411
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Objective: Pine wilt disease has been intensifying in China in recent years, and its pathogenic factor is pine wood nematode (Bursaphelenchus xylophilus), and it is a globally recognized quarantine pest. Esteya vermicola (EV) is an important biocontrol fungus infesting the pine wood nematode. The lunate spores produced by EV can infect and kill the pine wood nematode, thus EV has a good application prospect in the biological control of the pine wood nematodes. How to increase the growth rate, sporulation ability, and the virulence of EV to the pine wood nematode through cultivation, and then apply it to the field biological control is an important problem that needs to be solved urgently. Method: In this study, EV was cultured in carbon and nitrogen medium respectively, and the growth rate and spore production were determined. The mycelia were harvested and RNA was extracted for library construction and differential analysis. The corrected P-value (Padj) and the absolute value of the logarithm of the base 2 fold change (|log2FoldChange|) were used to judge the significance of the differential expression. Result: EV fungus grew fast under nitrogen culture conditions, and the total number of expressed genes and specifically expressed genes of EV fungi under nitrogen culture conditions were higher than those under carbon culture conditions. A total of 7 138 genes were significantly differently expressed in the nitrogen group compared to the carbon group, of which 3 571 genes were significantly up-regulated, and 3 567 genes were significantly down-regulated. There were 474 genes specifically expressed in the nitrogen group and 295 genes specifically expressed in the carbon group, and the number of genes specifically expressed in the nitrogen group involved nematicidal genes was greater than that in the carbon group. After cluster analysis, the variation trend of differential gene expression levels was divided into 4 clusters, among which there were 165 genes expressed much higher in the nitrogen group than in the carbon group; and 65 genes expressed much higher in the carbon group than in the nitrogen group. The expression of subtilisin and toxin synthesis-related genes involved in the activity of lethal nematodes and in the process of infecting nematodes were significantly up-regulated in the nitrogen group. The expression of subtilisin in the nitrogen group was 2.29-363.52 times higher relative to that in the carbon group. Conclusion: Carbon and nitrogen media have significant effects on the transcription of EV biocontrol fungi. The total number of genes and specifically expressed genes of EV fungi under nitrogen culture conditions are higher than those under carbon culture conditions. Subtilisin and toxin synthesis-related genes with nematicidal effects are significantly up-regulated under nitrogen culture. The research results will provide an important theoretical basis for the cultivation, gene function research and strain improvement of highly virulent EV strains, and then lay a foundation for improving the control efficacy of EV biocontrol fungi.

Risk Zones of Carpenter Bees for Wooden Structure of Ancient Buildings in China
Xingxia Ma,Lin Wang,Haiyan Zhu,Bo Liu,Bin Zhang,Yun Lu,Yanhua Wang,Mingliang Jiang,Liuru Wang
2021, 57(4):  116-123.  doi:10.11707/j.1001-7488.20210412
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Objective: This study was carried out to investigate the species diversity of carpenter bees and primary rating its damage in China with the aim to provide references for the preventive conservation project making on wooden structure ancient buildings based on the risk zones of carpenter bees (Xylocopa). Method: Research was implemented to collect literatures and specimen information of carpenter bee, and summarize the distribution of various carpenter bees, then analyze the nesting characteristics of carpenter bees and the degree of damage to the wooden structure, meanwhile investigate the degree of damage to the wooden structures of ancient buildings in each province and record the carpenter bees regarding to the hazards of the wooden structure of ancient buildings. A comprehensive comparison was also made to divide the risk area of wooden bee hazards of ancient wooden structures nationwide. Result: No carpenter bee was found in Heilongjiang, only Proxylocopa existed in Inner Mongolia, Qinghai, Xinjiang, Ningxia and Gansu beyond Longdong area, and no carpenter bee damage was found in the wooden structure of ancient buildings in these areas. In Tibet, Henan, Shanxi, Shandong, Liaoning, Jilin and Longdong area in Gansu, only one species of carpenter was found as the X.appendiculata. In Hubei, Shaanxi, Sichuan, Hebei, Anhui and Jiangsu provinces, there were two species of carpenter bees. Field survey results showed that mild hazards (hazard level 1) from carpenter bees appeared in Henan, Shanxi, Sichuan, Jiangsu and Anhui, however, hazards were relatively serious (hazard level 2 or above) from more than 3 species of carpenter bees in Yunnan, Guizhou, Hunan, Jiangxi, Guangdong, Guangxi, Fujian, Zhejiang, Hainan etc. Conclusion: The three risk zones (CB1, CB2 and CB3) of carpenter bees (Xylocopa) for wooden structure of ancient buildings in China could be classified based on the species diversity, distribution, nesting character and damage degree. CB1, the low risk zone, might include Heilongjiang (without carpenter bees damages), and Qinghai, Xinjiang, Ningxia, Western Gansu and Inner Mongolia (with only Proxylocopa). CB3, the high risk zone with serious damages by 3 or more species, might include Yunnan, Guizhou, Guangdong, Guangxi, Fujian, Hunan, Jiangxi, Zhejiang and Hainan. CB2, the moderate risk zone with slight damage by 1 or 2 species on wooden structure, might include the rest of China.

Double Layer Wood Hydrophobic System Construction Via Linseed Oil/Mixed Waxes Hybrid Emulsions
Cong Chen,Wang Wang,Jinzhen Cao
2021, 57(4):  124-132.  doi:10.11707/j.1001-7488.20210413
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Objective: The aim of current study is to improve the hydrophobicity and water repellency of wood by constructing double layer hydrophobic system in wood internal and external surfaces comprising a continuous linseed oil film with rough wax structure. Method: Linseed oil, mixed wax and oil/wax hybrid emulsions were prepared and their properties were tested. The two- and one-step impregnation process was used to modify cathay poplar (Populus cathayana), followed by the heat treatment at 70 ℃ (two-step process) or 90-103 ℃ (one-step process) to form double layer hydrophobic barrier. The internal morphology of samples was characterized by field emission scanning electron microscopy (FE-SEM), and the weight percent gain, surface hydrophobicity, water absorption and volume swelling rate of treated samples were measured. Result: 1) The average particle size of linseed oil emulsion was about 195.6 nm, and its change rate under 60 days room-temperature storage was only 2.45%. The wax/oil hybrid emulsions also presented great stabilities after centrifugation test. 2) FE-SEM images showed that both two- and one-step treatment processes could produce oil-wax double layer hydrophobic system with water repellent film and rough structures. 3) The initial contact angle of treated wood on cross sections was nearly 150° and kept a good stability within 80 s detection, the one-step process treated wood presented a better performance than that of the two-step on the tangential section. 4) The hybrid emulsions could further improve water repellency, and the water repellency efficiency(WRE) was above 35% and 45% with two- and one-step treatment, respectively. Clearly, one-step method performed better properties and simpler process. Conclusion: Linseed oil/mixed waxes hybrid emulsions could improve the hydrophobicity and water repellency of poplar at the same time, it may be an eco-friendly, energy-saving and low cost method for wood hydrophobic modification.

Analysis of Odorants in Cinnamomum burmannii Wood with Different Moisture Contents
Bin Zeng,Jun Shen,Qifan Wang,Huajun Dong
2021, 57(4):  133-141.  doi:10.11707/j.1001-7488.20210414
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Objective: The current research on the smell of wood was expected to provide a reference for solving the problem of "odor" emitted from wood used as an interior decoration material. Method: Taking Cinnamomum burmannii as the research object, the gas chromatography-mass spectrometry/olfactometry(GC-MS/O) technique was used to analyze the total volatile organic compounds(TVOC) and the characteristic odor active compounds released from the heartwood and sapwood under different moisture contents, and to explore the effects of moisture content on the TVOC and odor release of C. burmannii. Result: It was found that a total of 25 characteristic odor compounds were released from the C. burmannii, including benzene(aromatic), hexanal(green grass), ethylbenzene(aromatic sweet), benzaldehyde(almond oil), octanal(sweet incense), 2-ethyl-1-hexanol(sweet floral aroma), nonanal(fruit acid) and decanal(citrus smell) 8 key characteristic odor compounds. The concentration of odorant released by heartwood and sapwood at the initial moisture content of about 70% accounted for 64% and 72% of TVOC, respectively, mainly composed of alcohol and aldehyde odor compounds. As the water content decreased, the odorant substance and the total odor intensity released by the heartwood and sapwood showed a downward trend, and the odor intensity of the fruit flavor compound was always greater than the other characteristic odors throughout the changes of the moisture content. Before the moisture content decreased to 30%, the concentration of TVOC and odorant released from the heartwood and sapwood decreased the most significantly with the changes of moisture content. When the moisture content decreased to 30%, the concentration of odor substances released from the heartwood and sapwood decreased by 64% and 68%, respectively, and the overall odor intensity exhibited by the heartwood and sapwood was greatly reduced. Since then, the moisture content had less effects on the heartwood, but the sapwood concentration was also reduced by 26% when the moisture content continued to drop to 10%, and then it was almost unaffected by the moisture content during the entire moisture content declining processes. The amount of TVOC released by the sapwood was much larger than that of the heartwood. Among them, the compounds released from the heartwood were mainly aromatic hydrocarbons and ester compounds, those from the sapwood were mainly composed of alcohols and aromatic hydrocarbons, whereas the release of olefins in heartwood and sapwood remained stable at different moisture contents, and was less affected by moisture contents. Conclusion: Fruit aroma is the main characteristic smell of C. burmannii. The type and concentration of odor substances emitted by C. burmannii decreased with the decrease of moisture content, and the overall odor intensity also decreased accordingly. At any moisture content, the overall odor intensity of the sapwood is always greater than that of the heartwood. After the water content drops to the fiber saturation point, the released odorant material gradually becomes stable, and the odor characteristic compounds and the overall odor intensity released by the sapwood after the water content reaches the equilibrium moisture content might be also tend to stable.

Review
Advances in Research on Prediction Model of Moisture Content of Surface Dead Fuel in Forests
Long Sun,Qi Liu,Tongxin Hu
2021, 57(4):  142-152.  doi:10.11707/j.1001-7488.20210415
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Forest fire is one of the important factors that affect the forest ecosystem. The spread and development of forest fire are deeply affected by the moisture content of forest fuels, especially the occurrence of forest fire is directly affected by the moisture content of dead fuels on the surface. Therefore, accurate prediction of the forest surface dead fuels moisture content is the key to predict forest fire risk and fire behavior, and it is particularly important to strengthen the study of forest dead fuels moisture content prediction model. This article summarizes the research status of forest fuels moisture content in terms of the research methods, research models and model accuracy, and comparatively evaluates the existing models. In view of problems in the current research, five prospects for future research are proposed: 1) Strengthen research on the dynamic of fuel moisture content in key fire risk zone. The existing forest fire danger factor collection stations and forest fire danger monitoring stations are used to obtain the monitoring data of forest fuel moisture content and meteorological factors under different environmental condition. The prediction model of forest fuel moisture content based on meteorological parameters in key fire danger zone is constructed. 2) Strengthen basic data monitoring and collection of forest fuels. In order to build a comprehensive forest fire risk rating system, the basic data monitoring and collection of forest fuels should be strengthened, a solid data foundation should be laid, and an accurate forest fuel type classification system should be established. 3) Strengthen the study on the spatial heterogeneity of the fuel moisture content. In the future research, the dynamic changes of fuel moisture content under different impact factors should be considered, especially the spatial heterogeneity of fuel moisture content of small-scale forests, so that the prediction of forest fire danger can be made more accurately. 4) Improve the accuracy of the models combined with boosted regression tree(BRT). In the study of the influencing factors of the accuracy of the fuel moisture content model, the BRT method should be used to randomly extract a certain amount of data multiple times to analyze the degree of influence of different influencing factors on the accuracy of the model. 5) Conduct research on large-scale fire risk early alarm combined with GIS. Based on RS and GIS technology, the remote sensing inversion model of the fuel moisture content is established. On the basis of accurate simulation of the spatial distribution of forest fuel moisture content, the fuel moisture content prediction models of different fire risk classes is established.

Discussion
Performance Evaluation of Natural Forest Protection Project in State-Owned Forest Region——A Case Study of Key State-Owned Forest Region in Heilongjiang Province
Chaohong Li,Wei Wei,Shuxin Liu
2021, 57(4):  153-162.  doi:10.11707/j.1001-7488.20210416
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Objective: The key state-owned forest region in Heilongjiang Province was taken as an example for a relatively objective tracking evaluation of the performance of natural forest protection project, in order to provide a basis for the performance evaluation of natural forest protection projects in China. Method: A performance evaluation indicators system consisting of three subsystems of resources, industries and society was developed to evaluate the performance of natural forest protection project in the key state-owned forest region of Heilongjiang Province from 2000 to 2018 by using TOPSIS model based on entropy weight. Result: From 2000 to 2018, the performance values of the three subsystems of resources, industries and society, and the whole natural forest project system were respectively in the range of 0.019 0-0.748 0, 0.182 7-0.776 4, 0.010 0-0.782 2 and 0.018 8-0.753 2, showing a upward fluctuating trend on the whole. Conclusion: The entropy weight of the performance evaluation indicators system for the natural forest protection project based on the case study objectively reflects the main objectives of the natural forest protection project which focuses on natural forest protection and ecological environment construction, benefiting people's livelihood, promoting social harmonious development, and helping the industrial economic transformation and development of state-owned forest region. Compared with the "Phase Ⅰ Natural Forest Protection Project", the performance values of the three subsystems and the whole project system of the "Phase Ⅱ Natural Forest Protection Project" had been greatly improved, and their performance levels had all been transformed from "little changed" to "slightly improved" and then to "becoming better". By the end of 2018, all performance levels had reached "becoming better", but there was still one more level to reach the best performance level of "becoming very good".

Scientific notes
Effects of Elevated CO2 Concentration on Soil Microbial Functional Diversity and Carbon Source Utilization Characteristics in the Root Zone of Lycium barbarum
Yun Xie,Fangyun Guo,Lihua Chen,Bing Cao
2021, 57(4):  163-172.  doi:10.11707/j.1001-7488.20210417
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Objective: This paper studied the differences in the functional diversity and carbon source utilization characteristics of soil microorganisms in the root zone of Lycium barbarum, by which determined the effects of doubled CO2 concentration on the functional diversity of soil microorganisms in the root area of L. barbarum, so as to provide theoretical basis for sustainable management of L. barbarum. Method: In this study, the cuttings of L. barbarum(wolfberry) were used as materials. An open-top chamber (OTC) was used to set three CO2 concentration gradients of atmospheric CO2 concentration (CK, 400±20 μmol·mol-1), and 1.5-time atmospheric CO2 concentration (TR1, 600±20 μmol·mol-1), and 2-time atmospheric CO2 concentration(TR2, 800±20 μmol·mol-1). The wolfberry saplings were subjected to the different CO2 concentrations. Soil samples were collected from the root zone at 30, 60, 90, and 120 days after treatment and analyzed by BIO-ECO technology for the functional diversity of soil microbial communities and the characteristics of carbon source utilization. Result: 1) The microbial carbon source metabolic activity (AWCD) in the root zone of L. barbarum significantly increased with the increase of CO2 concentration. Compared with the control, the AWCD of 1.5-time and 2.0-time atmospheric CO2 concentration increased by 22.56% and 36.45%, respectively. 2) With the increase of CO2 concentration, the Shannon index and McIntosh index of soil microorganisms increased significantly. The Simpson index increased in the early stages of treatment, but there was no significant change in the middle and late stage of treatment. 3) The main carbon source of the soil microbial community in Ningxia wolfberry root zone was amino acids, esters and amines. Under the elevated CO2 concentration, the carbon sources with higher soil microbial utilization rate were mainly esters and amines, while the utilization rate of sugars and acids was lower. Under 2.0-time atmospheric CO2 concentration, the utilization and metabolism of L-arginine, L-asparaginic acid, Tween-40, phenethylamine, and 4-hydroxybenzoic acid were significantly higher than that of the control, but the utilization and metabolism of γ-hydroxybutyric acid were significantly lower than that of the control. 4) The increase of atmospheric CO2 concentration significantly affected the utilization of carbon sources in the soil microbial community in the root zone of wolfberry. Sugars and amines were the main carbon sources that differentiated the soil microbial community in different periods. Conclusion: Elevated CO2 concentration can significantly increase the activity of microbial communities and the utilization of carbon sources, and all increase the species richness, species dominance, and community uniformity of soil microbial communities in the root zone of wolfberry. The highest metabolic activity and diversity of soil microbial community treated with one time increase of atmospheric CO2 concentration were found. Among the six major types of carbon sources, amino acid, ester and amine carbon sources are the main carbon sources utilized and transformed by the soil microbial community in the root zone of wolfberry. The carbon source utilization rate of soil microbial community is the strongest at 60 days (July). Therefore, the increase of atmospheric CO2 concentration is the main reason for the differences in the metabolic diversity and carbon source utilization of soil microbial communities in the root zone of Lycium barbarum.

Effects of Different Nitrogen Forms and Supply on Photosynthetic Characteristics and Growth of Phoebe bournei Seedlings under Elevated CO2 Concentration
Xiao Wang,Xiaoli Wei,Gaoyin Wu,Shengqun Chen
2021, 57(4):  173-181.  doi:10.11707/j.1001-7488.20210418
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Objective: In this paper, the photosynthetic characteristics and growth performance of Phoebe bournei seedlings under different CO2 concentrations, different nitrogen forms and supply were studied to explore whether nitrogen fertilization could be used to regulate the photosynthesis of P. bournei seedlings. Method: One-year-old P. bournei seedlings were used as experimental materials. The open-top gas chamber was used for CO2 concentration treatment [ambient concentration: (350±70) μmol·mol-1; elevated concentration: (700±10) μmol·mol-1], and different amounts (medium dosage 0.8 g·plant-1, increased dosage 1.2 g·plant-1) of nitrate and ammonium were used to cultivate P. bournei seedlings. Result: Compared with ambient CO2 concentration treatment, after a long period of elevated concentration CO2 treatment (88 days), the net photosynthetic rate of P. bournei seedlings reduced by 26.93% (P < 0.05), and its Rubisco and RCA activity, soluble sugar, and starch, soluble protein content, seedling height and ground diameter were all significantly lower (P < 0.05) than those treated with ambient CO2. The photosynthetic down-regulation phenomenon of P. bournei seedlings eventually affected growth. Under long-term elevated CO2 concentration, the net photosynthetic rate of P. bournei seedlings subjected to increased nitrate or ammonium had no significant changes (P>0.05), its Rubisco and RCA activity, soluble sugar, starch, soluble protein content, and seedlings height and ground diameter increased or there was no significant change, indicating that increasing nitrate or ammonium nitrogen application can alleviate the adverse effects of long-term elevated CO2 concentration conditions on photosynthesis and growth of P. bournei seedlings. Conclusion: Under the condition of long-term elevated CO2 concentration, the application of increased nitrate or ammonium nitrogen can increase the activities of photosynthetic key enzymes, increase the content of organic matter, and eventually promote the growth of P. bournei seedlings to alleviate the negative impact of elevated CO2 concentration on the growth of P. bournei seedlings.

Establishment and Evaluation of Tree Competition Index Based on Intersection and Crowding
Xuefan Hu,Huiru Zhang,Guangshuang Duan,Jun Lu
2021, 57(4):  182-190.  doi:10.11707/j.1001-7488.20210419
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Objective: In order to provide a basis for better calculating the competition status of secondary forest of Mongolian oak and over-logged spruce and fir forest, a new competition index was constructed by adding the crowding to the competition index based on intersection angle. Method: Three representative plots of Mongolian oak secondary forest and three plots of over-logged spruce and fir forests with an area of 1 hm2 were selected in Tazigou and Jingouling forest farm of Wangqing Forestry Bureau, Jilin, China. The stands were investigated in 2013 and 2018, respectively. The competition index caCI based on intersection and crowding was constructed, dominant tree species were determined by dominance analysis, and the individual tree basal area growth model of dominant tree species was established to evaluate the competition index caCI, Hegyi, aCI and uaCI. Result: The results showed that caCI had a significant positive correlation with Hegyi, aCI and uaCI. The regression model and linear mixed-effects model of basal area growth showed that the basal area growth was positively correlated with the initial basal area, and negatively correlated with the competition index, suggesting that the major factor affecting the increment was the initial size of trees and that the competition among trees also had an effect on tree growth. The fitting accuracy of the linear mixed effect model was better than that of the regression model, which indicated that the growth dynamic of different tree species was significantly different, but the influence of the sample plot was slight. The fitting effect of the model with competition index was better than that of the model without competition index. Compared with Hegyi, aCI and uaCI, caCI showed the best performance in over-logged spruce-fir forests, followed by secondary forest of Mongolian oak, which indicated that caCI was suitable for forest with more complex spatial structure. Conclusion: The competition index caCI could effectively reflect the competition of secondary forest of Mongolian oak and over-logged spruce-fir forest, especially in the natural mixed forest with more complex forest structure.

Extractive Chemical Components of Quercus variabilis and Quercus acutissima
Yuan Chen,Tingting Yan,Sheng Yang,Zongying Fu,Gaiyun Li,Haiqing Ren
2021, 57(4):  191-198.  doi:10.11707/j.1001-7488.20210420
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Objective: This study focused on the extract content and chemical composition of different parts of oak, with the aim to provide scientific guidance for the processing and utilization of oak wood. Method: This study used the oak from Henan Province as the research object, using the Chinese wood chemical analysis standard, combined with Fourier transform infrared(FTIR) and gas chromatography mass spectrometry(GC-MS) method. The content and composition of the cold/hot water extract, 1% sodium hydroxide extract and phenyl alcohol extract from the bark, sapwood and heartwood with different heights in the trunk of Quercus variabilis and Quercus acutissima were analyzed in detail. Result: The results showed that the contents of cold/hot water and 1% NaOH extractives of Q. variabilis bark, sapwood and heartwood at different heights were significantly higher than those of Q. acutissima. Among them, the bark extractive had the highest content, the sapwood was the second, and the heartwood had the lowest content. The extract content had a tendency to be high at both ends and low in the middle with the height of the trunk. For the content of phenyl alcohol extract, the oak bark was much higher than the sapwood and heartwood, but the difference between two oaks was small and did not change with the height for the sap/hearwood. The FTIR spectra showed that the bark and sap/heartwood of Q. variabilis and Q. acutissima were obviously different. According to the absorption peak intensity, the bark might contain more alcohols, fatty acids, aromatics and alkane structural compounds, and there should be more acids, alcohols and unsaturated hydrocarbons in the sap/heartwood. The Result: s of GC-MS analysis showed that both the bark and sap/heartwood contained a small amount of alkane alcohols, esters and unsaturated alkenes. The bark contained abundant friedelin and its isomers. The sap/heartwood included γ-sitosterol et al. Conclusion: The main chemical components of the extracts of Q. variabilis and Q. acutissima in bark and sap/heartwood have a large difference, and there also have a certain difference in component contents. The height of the trunk also has a certain influence on the extract content of these two oaks. The middle trunk accumulated more cold/hot water and 1% NaOH extractives, but no significant compositional differences were found. In the actual processing and production of wood, the differences in the content and bark, sap/heartwood extractives of the two kinds of oak wood should be fully considered to provide a reasonable, comprehensive and high-value utilization processing plan.