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(Objective) The present paper aimed to clarify the diversity, distribution, and occurrence dynamics of the main pest communities in pure plantations of Melaleuca leucadendron and its mixed plantations with Eucalyptus plantations and Podocarpus macrophyllus in Guangxi, providing a basis for the cultivation of M. leucadendron and green non-pollution pest control. (Method In 2023, the planting areas of M. leucadendron in Qinzhou, Guangxi were investigated, mainly through route surveys and standard plot surveys, supplemented by fixed-point monitoring, regular surveys and indoor rearing observations. The study focused on the composition, diversity and occurrence dynamics of the main pest communities in M. leucadendron and its mixed plantations. (Result) There were 28 species of main pests belonging to 22 families in M. leucadendron plantations, including Hemiptera, Lepidoptera, Coleoptera, Orthoptera, Dermaptera and Thysanoptera, with the highest numbers of pests in the Lepidoptera and Hemiptera. Higher numbers were found in M. leucadendron Eucalyptus mixed plantations, with significant damage to leaves by Euricania ocellus, Bombotelia sp., Strepsicrates coriariae, Jankowskia fuscaria and Hyalopterus arundimis. Among the three types of stands, B. jocosatrix caused the most severe damage in the mixed plantations, the highest number of pest species was found in the mixed forests of M. leucadendron P. macrophyllus and the pest diversity was the lowest in the pure stands. The pest occurrence dynamics were more stable and the damage was less severe in the M. leucadendron x P. macrophyllus mixed plantations. There were differences in the abundance of pests and Chaol index among different stand types, with the M. leucadendron Eucalyptus mixed plantations having a higher pest abundance and Chaol index. The occurrence dynamics of B. jocosatrix and M. phaseoli varied among different stands, with the earliest outbreaks of B. jocosatrix in the M. leucadendron Eucalyptus mixed plantations and M. phaseoli in the pure M. leucadendron stands. (Conclusion】 Mixed plantations of M. leucadendron with different species can help improve pest occurrence and diversity, with the M. leucadendron x P. macrophyllus mixed plantations reducing the occurrence of major pests among the three stand types. [ABSTRACT FROM AUTHOR]

In this paper, data obtained by scanning 10 artificial Korean pine forests based on Terrestrial Laser Scanning (TLS), were combined with field survey data to construct tree height curve model, height to crown base prediction model and crown contact height prediction model, and a simultaneous equation system was established. First, from the five kinds of tree height curve models selected, two models with better fitting effects were selected as the candidate models of the simultaneous equations. Then one model with good fitting effect and high applicability from the five height to crown base models was selected as base model, and the stand factors (mean DBH of stand, stand basal area, ratio of height to diameter, mean DBH of dominant trees and mean height of dominant trees) were introduced into the basic model by means of re-parameterization and optimal subset regression, the model with better fitting effect was selected as the alternative model of height to crown base model. The same method was used to select alternative crown contact height model with good fitting effect. Finally, the tree height curve model, alternative height to crown base model and alternative crown contact height model were combined in pairs to establish simultaneous equations. Through seemingly unrelated regression estimation, the best equations were selected by the goodness of fit and the test results, and the simultaneous equations were evaluated. When the optimal simultaneous equation was used to estimate the tree height, the decision coefficient R² = 0. 896, and the root mean square error RMSE= 0. 612 m; when the equations was used to estimate the height to crown, R² = 0. 575, RMSE = 0. 850 m; when the equations was used to estimate the crown contact height, R² = 0. 719, RMSE= 0. 791 m, and all kinds of inspection indexes were good. On the whole, the equation system had better fitting accuracy and test effect for tree height, height to crown and crown contact height, and can solve the internal correlation problem of tree height, height to crown and crown contact height, which provided the basis for further study of crown structure and dynamic changes of Korean pine. [ABSTRACT FROM AUTHOR]

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Copyright of Forest Research is the property of Forest Research Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Remote Sensing is the property of Editorial Office of Journal of Remote Sensing & Science Publishing Co. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Forest Research is the property of Forest Research Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Forest Research is the property of Forest Research Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In order to reveal the effects of fertilization on the growth of Acacia saplings, experiments were carried out with combinations of Acacia varieties, application methods and fertilizer formulae, recording sapling changes in diameter at breast height (DBH), tree height and volume growth. The result showed that formulae of basal fertilizer significantly influenced DBH and volume growth except height growth; and formulae of surface dressing had no obvious effect on the sapling growth, while there were significant differences in sapling growth among varieties. Factors’ effects on the growth were in such a descending order: varieties > basal fertilizing > surface dressing. Among 9 treatments of orthogonal design, there were significant differences in tree height, DBH and volume (P < 0.05), and treatment A 1 B 2 C 3 and A 2 B 3 C 3 had highest tree height, A 3 B 2 C 2 had highest DBH and volume. This finding may provide insight for the management of Acacia plantations. [ABSTRACT FROM AUTHOR]

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To understand the soil′s physical and chemical properties as well as soil readily oxidizable organic carbon (ROC) content under different stand types, the physico-chemical properties, cation exchange capacity (CEC), ROC content, and other top soil indicators were studied in Schima superba and Eucalyptus urophylla plantations of 30 years old in Changgangshan Natural Reserve of Guangzhou, Guangdong Province. The results revealed that the contents of total soil organic carbon (TOC) and total nitrogen (TN) in Eucalyptus urophylla were significantly higher than those in S. superba. The C/N ratio in S.superba was significantly higher than that in Eucalyptus urophylla, whereas the C/P and N/P ratios in Eucalyptus urophylla were higher than those in S. superba. The soil CECs were not significantly different between the two stands. The total exchangeable base cations and base saturation percentage in Eucalyptus urophylla plantations were significantly higher than those in S. superba plantations. The contents of exchangeable base ions showed a trend of Ca2+＞Mg2+＞K+＞Na+. The ROC contents and ROC/TOC ratio in Eucalyptus urophylla were higher than those in S. superba, with significant differences in ROC between the two stands. The correlation analysis showed that the ROC content in Eucalyptus urophylla plantation had a significant positive correlation with AP (P＜0.05), where as the ROC/TOC was significantly positively correlated with TP (P＜0.05). ROC had a significant positive correlation with CEC in S. superba plantation (P＜0.05), and ROC had an extremely significant positive correlation with ROC/TOC (P＜0.01). We found that the ROC contents were significantly different between the two stand types, and ROC/TOC in S. superba was lower than that in Eucalyptus urophylla plantation, indicating that the soil carbon stability in S. superba plantation is stronger than that in Eucalyptus urophylla plantation thus resulting in higher carbon sequestration. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Tea Science is the property of Journal of Tea Science Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Geo-economic cooperation has driven or is driving land use/cover changes in national border areas globally. However, quantitative examination of bilateral impact-response and their relationship remains insufficient, or in an initial stage. Using the SERVIR-Mekong landcover products provided by the United States Agency for International Development, the loss of natural forest and its transformation processes towards cropland and plantations (including orchards) as well as their border-proneness in the border area (a buffer of 60 km) of Thailand and Laos from 1987 to 2015 were analyzed with GIS-based methods. The results showed: (1) Over 3. 18×104 km² of natural forest (including forest and mixed forest) loss was seen in the border areas in the past 30 years. The forest loss driven by farmland expansion in the Thai side was dominant, with a reduction of 72%; while the plantations (including orchards) caused over 2/3 of forest loss in the Laotian side. (2) Deforestation due to the expansion of cropland and plantations was significantly notable circa 2000, or between 1999 and 2003 in both sides, accounting for over 40%, which was concentrated in the surrounding area of major border cities (e. g.,Vientiane) or crossing ports (e. g., Chiang Khong and Nongkhai, Thailand). (3) The loss amount of forest and mixed forest on both sides increased as it gets closer to the borderline. The deforestation of forest and mixed forest due to farmland conversion and the conversion of forest into plantations (including orchards) in the Laotian side displayed a more obvious border-proneness; while the deforestation of mixed forest because of the conversion into plantations (including or‐ chards) in both sides displayed strong convergence. (4) The forest/mixed forest reduction caused by the expansion of farmland was primarily seen within 45 km on both sides, while the forest loss (within 13 km) caused by the expansion of plantations (including orchards) was more significant than that of mixed forests. [ABSTRACT FROM AUTHOR]

To explore whether there were substances that inhibit seedling growth in the litter of Pinus sylvestris var. mongolica, understand the barriers to seedling survival in P. sylvestris var. mongolica plantations, clarify the effects of litter and its extract liquid on seedling physiological properties and growth of P. sylvestris var. mongolica. In this study, P. sylvestris var. mongolica seedlings were cultured in pots with different concentrations of leaf litter extract liquid, set to 12.0, 6.0, 3.0, and 1.5 g·L-1, and leaf litter cover, set to 4.30, 2.15, 1.08, and 0.54 kg·m-2. The results showed that: 3.0 g·L-1 of leaf litter extract liquid treatment and 2.15 kg·m-2 of leaf litter cover treatment promoted seedling growth, with the synthetical allelopathic index（Mr) 0.10 and 0.17, respectively; the malondialdehyde content in seedling leaves was significantly（P＜0.05) increased by the 12.0 g·L-1 leaf litter extract liquid and 0.54 kg·m-2 leaf litter cover treatments, which were 37.48% and 88.15% higher than that in the control, respectively; compared with CK, all treatments inhibited photosynthetic pigment content in seedling leaves by 17.6%-49.6%. The soluble protein content of the seedling leaves increased by 0-23.14%. Peroxidase activity of seedling roots increased by 149.76%-1 887.13%; 6.0 g·L-1 of leaf litter extract liquid and 2.15 kg·m-2 of leaf litter cover treatment had the strongest promoting effects on seedling physiological indexes, with Mr values of 0.39 and 0.12, respectively. In conclusion, the extract liquid of the leaf litter of P. sylvestris var. mongolica showed a mass concentration effect of "low concentration promotion and high concentration inhibition" on the seedling growth of P. sylvestris var. mongolica. Leaf litter cover of P. sylvestris var. mongolica in sandy land maintained at 2.15 kg·m-2 was conducive to seedling growth, but not at concentrations below 0.54 kg·m-2. [ABSTRACT FROM AUTHOR]

Forty-year-old Chinese fir (Cunninghamia lanceolata) plantations from 16 different provenances in China were selected as the study object to identify the differences in the phenotypes of the anatomical traits of their fine roots, and the characteristics of the responses of the functional traits of fine roots to different geographical environments were analyzed. The fine root diameter (FRD), stele diameter (SD), cortical thickness (CT), ratio of stele to root diameter (SDR), and ratio of cortex to cross-section (CCS) of the fine roots were measured. The differences in the anatomical traits of the fine roots of Chinese fir were compared at the distribution area level, and the correlation between these anatomical traits and environmental factors were examined. The findings revealed significant differences in the anatomical traits of the fine roots among the different provenances (P＜0.05). The FRD and SD of the fine roots of Chinese fir in different locations were ranked in the following descending order: northern belt＞east of middle belt＞center of middle belt＞west of middle belt＞southern belt. The FRD and SD of the fine roots of the trees in Shanghang (Fujian) and Xinyang (Henan) were larger than those in the other provenances, whereas those of the fine roots of the trees in Shangrao (Jiangxi) were the smallest. The CT of the fine roots of Chinese fir in the different areas decreased in the following order: northern belt＞west of middle belt＞east of middle belt＞center of middle belt＞southern belt. The CT of the fine roots of trees in Xinyang (Henan) was thinner than that in other provenances, whereas the fine roots of the trees in Shangrao (Jiangxi) and Luotian (Hubei) showed thicker cortical tissue. The results of redundancy analysis showed that the CT and CCS of the fine roots positively correlated with the soil phosphorus content and significantly negatively correlated with the soil nitrogen content (P＜0.05). The SDR of the fine roots showed a significant positive correlation with latitude (P＜0.05) and a significant negative correlation with soil phosphorus content (P＜0.05). The response characteristics of the anatomical traits of the fine roots of Chinese fir in different habitat conditions differed, indicating that the fine roots of Chinese fir produce variations in functional traits and implement various ecological strategies to adapt to the environmental conditions in different provenances. [ABSTRACT FROM AUTHOR]

In order to solve the problem of compatibility between tree factors and their growth models, the integrated stand growth model of Larix kaempferi plantation in the mountainous area of western Hubei was established by using nonlinear measurement error simultaneous equations method. The results showed that the nonlinear measurement error simultaneous equations method can ensure the compatibility and unbiasedness of the model. The mean relative error and relative mean square error of each stand factor were below 6. 5%, and the model parameter stability and prediction accuracy were high. The established integrated stand growth model can be used for stand growth and harvest prediction, quantitative thinning operation design and stand density control diagram drawing of Larix kaempferi plantations with different initial conditions. It can provide scientific reference for efficient and sustainable management of Larix kaempferi plantation in the study area. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Guangxi Normal University - Natural Science Edition is the property of Gai Kan Bian Wei Hui and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Forest Research is the property of Forest Research Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The Flux Variance Similarity (FVS) method can directly decompose the ecosystem evapotranspiration components based on the observation data of the eddy covariance method. This method needs to calculate the key parameter Ci/Ca (ratio of intercellular CO2 concentration to atmospheric CO2 concentration), so the research and construction of the Ci/Ca model plays an important supporting role in the application research of FVS method. In this study, the poplar plantation was taken as the research object, and the transpiration was calculated by the concurrent eddy covariance (CEC) method. Four existing Ci models were inverted, evaluated and optimized: Constant Ci model, Constant Ci/Ca model, Linear model and Katul model. The results showed that the diurnal changes of ecosystem transpiration and soil evaporation based on CEC split showed obvious unimodal curves, and the peak of evaporation appeared before the peak of transpiration. The partitioning results for 83 consecutive days also showed obvious diurnal variation characteristics. TR/ET(transpiration/evaportranspiration), daily transpiration and daily evaporation are 0.78, 2.46 and 0.63mm, respectively; linear regression deviation was calculated between TR measured by CEC and simulated of FVS method based on Const&lowbar;Ci model, Const&lowbar;k model, Linear model and Katul model. The deviation rates were 59%, -16%, -70%, and -31%, MAE were 0.18, 0.069, 0.21 and 0.085mm·h-1, and RMSE were 0.25, 0.089, 0.27 and 0.10mm·h-1,respectively. Compared with the original Katul model, the optimized Katul model and VPD0.26 model after parameter optimization have significantly improved accuracy in estimating canopy transpiration. MAE were 0.048 and 0.047mm·h-1, and RMSE were 0.058 and 0.057mm·h-1, and Pearson correlation coefficients were 0.83 and 0.73, respectively. It is feasible to apply the optimized Katul model for FVS to directly separate evapotranspiration components of poplar plantation ecosystem. [ABSTRACT FROM AUTHOR]

Copyright of Forest Research is the property of Forest Research Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Forest Research is the property of Forest Research Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The aim of this study was to understand the effect of soil nitrogen concentration on the total carbon, nitrogen, and phosphorus (TC, TN, and TP) contents and nutrient reabsorption efficiency of Pinus tabuliformis needles and its change with age. Taking four age classes (II,III,IV and V) of Pinus tabuliformis in Jintan Forest Farm in Shanxi Province as the research object, five nitrogen application levels were set up in a short-term nitrogen addition experiment: CK(0 g·m-2·a-1), N1 (5 g·m-2·a-1), N2 (10 g·m-2·a-1), N3 (15 g·m-2·a-1), and N4(20 g·m-2·a-1). Subsequently, we measured the nitrogen content of the surface soil (0-30 cm) corresponding to five nitrogen application levels of four age classes and the TC, TN, and TP contents of mature needles and fallen leaves under the corresponding nitrogen content of surface soil. Additionally, the TC, TN, and TP contents of mature needles and their stoichiometric ratios and the corresponding nitrogen and phosphorus nutrient reabsorption efficiency were calculated and analyzed. The TC, TN, and TP contents in the needles of Pinus tabuliformis plantations at all ages showed a single peak trend of first increasing and then decreasing with increasing soil nitrogen content, ranging from 509.7-540.5, 7.78-12.81, and 1.97-3.36 g·kg-1, respectively. The C: N and C: P ratios showed a single peak change, and the N: P ratio showed a straight upward trend. The C: N, C: P, and N: P ratios ranged from 40.99-65.67, 157.06-266.28, and 2.95-5.12, respectively. When the soil nitrogen content was fixed, the needle TC content increased with the age class, and the TN content reached the maximum in the third age class, whereas TP content decreased with age. Except for the C: N ratio, the metering ratio increased with age. The nitrogen reabsorption efficiency of needles in the fifth age class was relatively stable with the increase in the soil nitrogen content, and the remaining age classes showed a continuous decreasing trend. The phosphorus reabsorption efficiency of the needles at the third age showed a trend of increasing first and then decreasing, and the rest showed a trend of increasing continuously. The nitrogen reabsorption efficiency increased with the increase in age class, and the phosphorus reabsorption efficiency first decreased and then increased with the increase in age class. The growth of Pinus tabuliformis plantation in this area was severely affected by N, and the N limitation was relieved with the increase in soil nitrogen content and age class. [ABSTRACT FROM AUTHOR]

Here, we aimed to understand the effects of nitrogen (N) -fixing and non-N-fixing tree species on the stoichiometric characteristics of soil carbon (C), N, phosphorus (P), and soil readily oxidized carbon (ROC) in south China. We determined the levels of soil total organic C (TOC), total N (TN), total P (TP), and ROC in 13-year-old Acacia crassicaipa and Eucalyptus urophylla plantations in Heshan, Guangdong Province, to analyze their characteristics and correlation of N-fixing and non-N-fixing tree species after afforestation. The results showed that soil ROC and TOC contents in N-fixing tree stands were significantly higher than those in non-N-fixing tree stands (P＜0.05), and ROC/TOC values were lower in the N-fixing than the non-N-fixing tree stand soils, indicating that soil C stability was improved in the N-fixing tree stand soils compared to the non-N-fixing tree stand soils. The soil TN content and C: N value were significantly higher in the N-fixing stands than in the non-N-fixing stands (P＜0.05). Soil C: P, N: P, and C: N: P were higher in the N-fixing stands, but the differences were not statistically significant. Soil TOC and TN were positively correlated in both stands (P＜0.01). In N-fixing stands, soil TOC and TN were negatively correlated with ROC/TOC (P＜0.05), and soil water content (SWC), C: P, and N: P were significantly positively correlated with TOC (P＜0.05). In south China, where SWC is high, afforestation with N-fixing trees increased soil TN and TOC contents and soil stoichiometric ratio, which helped improve soil C stability. [ABSTRACT FROM AUTHOR]

The aim of this study was to investigate the efficiency of plantation riparian buffer strips of different widths and densities in removing phosphorus in runoff water to reduce pollutants in water and mitigate agricultural non-point source pollution in Taihu Lake. We examined six buffer strips (20 m × 40 m) of Taxodium 'Zhongshanshan' and poplar plantations in the Taihu Lake area. The effects of riparian buffer zones with varying widths (15, 30, and 40 m) and densities(400, 1 000, and 1 600 tree·hm-2) on the removal of total phosphorus (TP) and dissolved phosphorus (DP) from runoff water were evaluated. The results showed that: (1) the optimum width of riparian buffer strips differs between plantations. A 15 m wide buffer zone of Taxodium 'Zhongshanshan'plantation and a 30 m zone of poplar plantation is sufficient for trapping phosphorus. (2) The average retention rates of TP and DP in the buffer zone of Taxodium 'Zhongshanshan' plantation with the different stand density were 1 000 tree·hm-2＞400 tree·hm-2＞1 600 tree·hm-2 and 1 600 tree·hm-2＞1 000 tree·hm-2＞400 tree·hm-2, respectively. The average retention rate of TP was 87.97% in the poplar buffer zone with 400 tree·hm-2. When the stand density was 1 600 tree·hm-2, the average retention rate of DP in the poplar plantation buffer reached 99.42%. (3) At different stand densities, the retention rate of TP was higher in Taxodium 'Zhongshanshan' plantation than in poplar plantation, but the difference was not significant. The DP retention rate in the buffer zone of 1 600 tree·hm-2 in Taxodium 'Zhongshanshan' plantation was significantly higher than that of poplar plantation (P＜0.05). When the stand density was 400 tree·hm-2, the average elimination efficiency of DP in the buffer zone of poplar plantation was higher than that in Taxodium 'Zhongshanshan' plantation. The Taxodium 'Zhongshanshan' plantation buffer strip with a width of 15 m and 1 000 tree·hm-2 can effectively reduce agricultural non-point source pollution in Taihu Lake. [ABSTRACT FROM AUTHOR]

In order to solve the problem that there are few site index tables compiled with DBH as index and the feasibility of using DBH as factor to evaluate site quality, in this study, the DBH growth equation was fitted with the long-term accumulation analytical data of Chinese fir trunks, the difference equation of DBH and the site index table of Chinese fir plantation in Hubei Province were constructed. The accuracy test and point test were used to test and compare the guide curve and the site index table respectively to evaluate the tabulation accuracy and applicability. The results showed that, 1) both the basic equation and the difference equation using the analytic data to fit DBH had good goodness of fit. 2) using the Korf basic equation and Korf difference equation, the single form site index table and the polymorphic site index table of Chinese fir plantation in Hubei province was compiled by using the guide curve method, taking 20 a as the standard age and 2 cm as the exponential level. 3) both the established model and the site index table passed the test, and the test accuracy of the difference equation was 99. 61%, higher than 96. 97% of the basic equation. The polymorphic site index table was 1. 18% higher than single form site index table. It can be seen that, the index table of DBH site of Chinese fir plantation in Hubei province compiled by difference equation is more accurate than the basic equation and can evaluate the site quality of Chinese fir plantation in Hubei province more accurately. [ABSTRACT FROM AUTHOR]

Taking a 30-year-old Pinus sylvestris var. mongolica plantation in the sandy land of Hulunbeier Forest-grass transition area as the research object, the forest gaps formed after natural disturbance were divided into four area(S) grades (Ⅰ: S≤50 m 2,Ⅱ: 50m 2 100 m 2 ), and the gap position was divided into gap center, near gap center, gap border and non-gap. And the species diversity under the gap of different area grades and position was analyzed. The results showed that: only the richness index R0(number of species), Simpson index, Shannon-Wiener diversity index and Pielou index in Ⅱgrade gap were significantly different from those of other forest gaps and non-gap in different area grads of Pinus sylvestris var. mongolica plantation in the sandy land (P<0.05). There were significant differences in richness index, Simpson index and Shannon-Wiener index between gap center, near gap center, gap border and non-gap, respectively. The order of the species richness index from large to small was near gap center, gap center, gap border and non-gap. In Conclusion, the formation of forest gap can significantly improved plant richness of Pinus sylvestris var. mongolica plantation in the sandy land, promote understory species diversity, and suitable size of forest gap had positive effect on species composition. [ABSTRACT FROM AUTHOR]

In order to screen out plant extracts with better antibacterial activity against anthracnose in Xihu Longjing tea producing area, the pathogens of tea anthracnose in this region were isolated and identified, and the inhibition activities of 12 plant extracts on the identified pathogen were determined using mycelial growth rate method. Concentration gradient test was further used to determine the antibacterial virulence of the top 3 plant extracts. The results show that Colletotrichum camelliae was the major pathogenic strain in the study region. At the concentration of 200 mg⋅L-1, the antifungal activities of vitriol, oregano essential oil and perillal aldehyde were better, and their inhibition rates on the growth of anthrax were all above 68%, and their effective medium concentrations (EC50) were 71.459, 77.155 mg⋅L-1 and 110.753 mg⋅L-1, respectively. Microscopic observation shows that the mycelium morphology of C. camelliae had obvious changes in the medium when supplemented with above plant extracts, showing deformation, distortion, shrinkage and shriveled. These results indicate that carvacrol, oregano essential oil and perill aldehyde have strong antibacterial activities against C. camelliae and possess potential for development as plant-derived fungicides. [ABSTRACT FROM AUTHOR]

The lack of nitrogen and phosphorus elements is the main limiting factor for plantation cultivation, in order to understand the responses of nitrogen and phosphorus fertilization on the tree and soil nutrient characteristics of Fraxinus mandshurica plantation, in this study, the effects of nitrogen (N0 0 g/m², N1 5 g/m², N2 20 g/m²) and phosphorus (P0 0 g/m², P1 7. 5 g/m², P2 15 g/m²) fertilization on the ecological stoichiometry of leaf, fine root and soil were analyzed in a 16-year-old Fraxinus mandshurica plantation. The results showed that: with the increase of nitrogen supply, the C and N content of leaf and fine root, and the N content of soil were significantly increased in the Fraxinus mandshurica plantation, while the P content of fine root and C/N ratio of leaf was significantly decreased (P<0. 05). Meanwhile, the C/P ratio of leaf and N/P ratio of fine root was significantly increased under P addition. With the increase of P supply, the P content of leaf, fine root and soil increased gradually, and the C/P and N/P of leaf and fine root decreased significantly under N0 treatment. Correlation analysis showed that, soil N content was significantly positively associated with leaf and fine root N content (P<0. 05), but significantly negatively correlated with leaf and fine root C/N content (P<0. 05). There were significant positive correlations between leaf N content and fine root N content, leaf P content and fine root P content, leaf C/N and fine root C/N, leaf N/P and fine root N/P (P<0. 05). The results showed that the nutrient status of Fraxinus mandshurica leaf after mixed application of nitrogen and phosphorus fertilizers was better than that after nitrogen or phosphorus fertilization alone. After fertilization, the stoichiometric ratios of fine root and leaf in the Fraxinus mandshurica plantation were significantly positive, it meant that the nutrient allocation of the leaf and fine root had a good synergistic action in the Fraxinus mandshurica plantation. [ABSTRACT FROM AUTHOR]

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Copyright of Forest Research is the property of Forest Research Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Irrigation & Drainage is the property of Journal of Irrigation & Drainage Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Forest Research is the property of Forest Research Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Heavy metal pollution in Kandelia obovata ecosystem is an important part of coastal wetland research. In order to explore the health risk and heavy metal pollution of K. obovata wetland of different origins in eastern Fujian, this study explored the content characteristics of heavy metals in surface sediments of different origins of K. obovata wetlands and assessed their health risks in East Fujian by using the pollution load index method and human health risk assessment method. The results were as follows:(1)The average contents of heavy metals in surface sediments of K. obovata natural forest wetlands were Zn(102.38 mg·kg-1)> Pb(101.53 mg·kg-1)> Cu(11.72 mg·kg-1)> Cd(0.91 mg·kg-1). The order of heavy metal contents in surface sediments of K. obovata plantation was Zn(152.81 mg·kg-1)> Pb(105.83 mg·kg-1)> Cu(16.38 mg·kg-1)> Cd(1.33 mg·kg-1).(2)The regional pollution load index(IPL zone)of heavy metals in surface sediments of K. obovata natural forest was lower than that of K. obovata plantation, and the corresponding pollution levels of K. obovata plantation and natural forest were both one, which belonged to moderate pollution.(3)The non-carcer risk(RN)of heavy metals in surface sediments of K. obovata wetlands to adult males and adult females was lower than one, and the RN to human body was very low. The RN of Pb element to children was higher than one, it would cause RN to children. The carcer risk(cancer risk, RI)of Cd to adult males, adult females and children was greater than 1.0×10-6, and there was a serious RT to the human body. The results indicate that heavy metal pollution of wetlands in East Fujian was serious. Therefore, we should control the pollutant emission around the wetland and purify the wetlands. In addition, adding the health risk assessment of heavy metals to the evaluation of K. obovata wetland ecosystem will help to strengthen the ecological protection and risk management of K. obovata. [ABSTRACT FROM AUTHOR]

Topographic factors have been confined to the temporal and spatial changes of land use and resource allocation in mountainous heritage areas. Taking the Core Area of Hani rice Terraces as the study area, this study aims to explore the geo-spectrum of land use and topographic gradient, thereby enchancing the landscape integrity and ecological service function of terraced fields for sustainable development. The land-use types were first classified as grassland, road, construction, shrub, dry land, bare land, tree, plantation, paddy field, river, and garden using Google Earth 0.55m×0.55m high-precision historical images in 2005, 2010, 2015, and 2020. After that, the transfer matrix was calculated to determine the geo-spectrum, distribution index, topographic index (TI), hypsometric index (HI), slope length factor, slope steepness factor (LS), topographic wetness index (TWI), the temporal and spatial variation of land use and topographic gradient in the study area from a long time scale and a complete spatial range. A field test was finally conducted to verify the data using visual interpretation. The results showed that: 1) The main types of land use in the study area were the arbor woodland and paddy field, followed by the dry land and shrub land from 2005 to 2020. Specifically, there was an annual increase in the arbor forest, garden land, plantation land, road, and house building, where the comprehensive growth rates were 12.73%, 148.32%, 118.68%, 138.76%, and 70.58%, respectively. The reduction rates of the paddy field and dry land were -16.56% and -28.56%, respectively. The water areas fluctuated from 0.28 km² in 2005 to 0.69 km² in 2020, where the overall growth rate was 147.27%. By contrast, there was a fluctuated reducing trend in the shrub land and grassland with the comprehensive decreasing rates of -10.87% and -29.58%, respectively. 2) The information maps illustrated the stable, continuous, and repeated types of land use, accounting for 37.43%, 25.36%, and 18.41%, respectively. The stable type was the paddy field and arbor forest land, concentrating mainly on the low LS gradient and high TWI gradient. The continuous change type was from the grassland to the arbor forest, and from the paddy field to the plantation, focusing on the low TI gradient and high LS gradient. The recurrent variations were mainly in the paddy-dry land and arbor-shrub forest, concentrating on the low HI, high LS, and low TWI gradient. The land use map in the study area presented a significant effect of terrain gradient on the HI, LS, and TWI indices, indicating the dynamic characteristics of the terrain, erosion intensity, and potential spatial variation of soil moisture. Consequently, the dynamic mechanism of terrain gradient was effectively interpreted using the information maps of land use. 3) Some recommendations were addressed: (1) To strengthen the main connection of “point (village) - axis (water system, ditch) - surface (forest and terraced fields)”, as the tourism developed; (2) To implement the differential development and complementarity of different terraced gradient areas; (3) To maintain the current characteristics of the stable areas in the geo-spectrum, while optimizing the spatial structure of the pre-change and intermediate change areas, and slow down the expansion of the late-change type; (4) To promote the continuously and repeatedly changing areas to the stable type in the heritage areas. [ABSTRACT FROM AUTHOR]

In order to provide theoretical reference for the near natural management of larch plantation, this paper takes larch plantation as the research object, and analyzes the root biomass and spatial distribution of 0-10 cm, 10-20 cm and 20-30 cm in larch medium-aged forest thinned in different gaps, larch near mature forest with different thinning intensity and larch mature forest with different clear cutting bandwidth. 8 points were selected in each stand, and samples were taken according to the depth of 0-10 cm, 10-20 cm and 20-30 cm. After washing, the roots <2 mm, 2-5 mm and >5 mm were dried and weighted, and the diameter distribution and spatial distribution law of the roots of larch plantation under different cutting methods were analyzed. The results showed that: the total root biomass of larch plantation was significantly different with different cutting methods (P< 0.05). The total root biomass of 5 m×5 m and 7 m×7 m gaps was 23.07% and 22.39% higher than the contrast. The root biomass of 30% thinning intensity was the highest (15.03 t/hm²), and the root biomass of 30 m clear-cutting width was the highest (11.33 t/hm²). The total root biomass of the stand decreased with the increase of soil layer. The root biomass of 0-10 cm soil layer accounted for the highest proportion of the total root biomass (about 70%), and the root biomass of <2 mm accounted for the largest proportion of the total root biomass of this soil layer (about 75%). The percentage of fine root biomass in the total root biomass of <2 mm of the cutting stand was significantly higher than that of the control stand. It showed that: the total root biomass of the stand could be increased in different degree for the close-to-nature management with gap thinning of 7 m×7 m for middle-aged plantation, even thinning of 30% intensity for near-mature plantation and strip clear cutting of 30 m width for mature plantation. [ABSTRACT FROM AUTHOR]

Copyright of Forest Research is the property of Forest Research Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Arid Zone Research / Ganhanqu Yanjiu is the property of Arid Zone Research Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Forest Research is the property of Forest Research Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Forest Research is the property of Forest Research Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In order to study the growth relation model between tree height and DBH of Cyclobalarwpsis glauca plantation, Cyclobalarwpsis glauca plantation in Jiufeng National Forest Park Wal! taken 81! the research object. 484 groups of tree height and DBH data were divided into modeling data and test data, and 10 common tree height curve models were selected to fit the modeling data respectively. The results showed that all the 10 tree height curve models reached extremely significant level ( P < 0. 01), among which the quadratic curve model had the smallest SSE and RMSE and the largest Jf, which accorded with the screening principle of the optimal model. The residual analysis of the optimal model showed no significant difference, and there was no significant difference between the predicted and measured tree height values obtained by substituting test data into the optimal model (Sig. = 0. 159 > 0. 05). The conclusion showed that the quadratic curve model could effectively predicted the height of Cyclobalarwpsis glauca plantation. [ABSTRACT FROM AUTHOR]

[Objective] This paper aimed to study the mechanisms of nutrient intake and utilization in jackfruit. [Method] The leaf contents of N, P, K, Ca, Mg, Fe, Zn and B in three varieties, 'GHsj1804', 'GHsj1806' and 'GHsj1808', were analyzed using samples collected at half-month interval from March to January. [Result] Annual dynamics varied with nutrients, but was similar with varieties; The mean nutrient concentrations of N, K, Ca, P, Mg, Fe, Zn and B were 13.7068 g/kg, 2.9383 g kg, 2.7909 g/kg, 1.4915 g/kg, 510.37 mg/kg, 191.54 mg/kg, 79.3998 mg/kg, 6.7284 mg/ kg, respectively; Contents of same nutrient in leaves at different positions correlated significantly, with a varied correlations values among different varieties; Correlations among different nutrient varied with varieties and leaf positions, and in all 3 varieties, Mg and K ( 0. 85 -0. 90), N and P ( 0. 50 -0. 69 ) correlated significantly. [Conclusion] When using results of leaf analysis as guidelines for fertilization, the factors such as plantation conditions and varieties should be considered seriously. [ABSTRACT FROM AUTHOR]

In order to accurately understand the land use change trend in the Liaohe River Basin of Jilin Province, and provide basic data for sustainable land use and ecological restoration technologies, this study collected basic data such as vector data and local history records of forestry, land, water conservancy, surveying and mapping, agriculture committee, meteorology and other departments in 9 cities and counties(districts) in Jilin Province, and retrieved relevant literature, standards, technical procedures(specifications), at the same time, combined with on-the-spot investigation, then the methods of remote sensing image classification and land use status classification were used to treat, analyze and judge the land use status in different periods in the Liaohe River Basin. The results showed, the main land use types in the Liaohe River Basin in 1970 s were mainly arable land, grassland and swamp, in the nearly 50 years from 1970 s to 2016, the area of swamp wetlands and grassland in the Liaohe River Basin of Jilin Province had been greatly reduced, the area of arable land and residents’ construction land had increased significantly, and the area of wood land, paddy fields and water bodies had increased slightly. Land use had gradually been converted to land use types such as arable land and residential construction land, which had strong manual intervention, especially for the increase in residential construction land. In the central and western cities of Siping, Lishu and Shuangliao, the land use types of grassland and swamp had been drastically reduced, the increasing area of arable land, residential land and plantation forest had become a major development trend, while the Liaoyuan area in the southeastern part, it showed that natural forests were decreasing, and the arable land and residential land were increasing. [ABSTRACT FROM AUTHOR]

The objective of this study is to explore the relationships between stand growth and site factors in young Mongolian Scots pine (Pinnus sylvertris var. 11Wngolica) plantations across the introduction areas in the eastern mountainous region of Northeast China. Using the method of plot investigation and analysis of average and dominant tree, the data of sample plots and stem analysis trees were investigated and collected. General linear model ( GLM) approach was used to quantify the effects of site factors on stand growth, with correction for the effects of stand conditions. Our study showed that the main site factors varied greatly across the region. Slope position, steepness, and soil layer depth in the southern part of Xiaoxing' anling mountains, soil layer depth in the western part of Zbangguangcailing mountain, slope steepness and the depth of black soil layer in the eastern part of Zhangguangcailing mountain, soil layer depth and slope steepness in Changhaishan molllltain, slope steepness in the southern part of Daheishan mountain, and slope position in the southern part of Daheishan mountain were main site factors, respectively. Our findings, together with other related research results, suggested that soil thickness was the leading factor, and the slope steepness, orientation and position associated with the increase depth of the soil layer would enhance the growth of Mongolian Scots pine plantations in the eastern mountainous region of Northeast China. [ABSTRACT FROM AUTHOR]

【Objective】The present paper aimed to compare overall characteristics of Sterculia nobilis Smith strains plantation in southwest Guangxi and provide a reference basis for qualified S. nobilis Smith strains screening and species cultivation.【Method】Comprehensively compare and investigate the flowering and fruiting habits,agronomic traits,stress resistance,and economic traits of six excellent strains of S. nobilis Smith planted in southwest Guangxi(NY2,LH2,SK14,SJ30,BJ32,and BJ33),and evaluate other traits,including yield and fruit quality,of the six strains by DTOPSIS.【Result】There were some differences in flowering and fruit habits,agronomic traits,stress resistance and fruit traits among different lines. Among them,SK14(14.86 kg) and BJ33 strains(14.50 kg) showed the highest yield per plant,without significant difference(P>0.05,the same as below),which were significantly higher than the other four strains(P<0.05,the same as below).No significant differences were found in yield per plant among the four strains. The single fruit weight of SK14(65.3 g) was the heaviest,extremely significantly heavier than that of NY2,LH2 and BJ32 strains(P<0.01,the same as below),and significantly heavier than that of SK14 and SJ30 strains. BJ32 had the highest seed production rate(58.6 %),which was extremely significantly higher than NY2,SK14 and SJ30 strains,and significantly higher than BJ33 strain. The single seed weight of SK14 was only 5.90 g,which was extremely significantly lower compared with the other five strains. The differences among the five strains were not significant. NY2 had the lowest pod boring rate(5.2 %),extremely significantly lower than SK14 strain,and significantly lower than LH2,BJ32 and BJ33. The starch content of SK14 was the highest(65.899 %),which was very significantly higher than that of NY2,LH2,SJ30 and BJ32 strains. The soluble sugar content of BJ32 was the highest(27.496 %),extremely significantly higher than that of NY2,LH2 and BJ33 strains,and significantly higher than that of SK14 and SJ30 strains. The soluble protein content of SJ30 was the highest(11.808 mg/gFW),which was very significantly higher than that of BJ33. No significant differences were found in soluble protein content among SJ30,NY2,LH2,SK14 and BJ33. DTOPSIS evaluation demonstrated that BJ33 had the highest score,C_i was 0.8336,and the optimal comprehensive characters.【Conclusion】BJ33 has strong tree vigor, high yield, filled fruit, big seed, high seed production rate, good quality and taste. It has the optimal comprehensive evaluation and can be developed as good S. nobilis Smith variety. SK 14, BJ 32 and NY2 has fine performance on single trait, and can be used as genetic resources in variety improvement. [ABSTRACT FROM AUTHOR]