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By introducing the local density factor into the taper equation, five Larix olgensis plantations in Mengjiagang Forest Farm, Jiamusi City, Heilongjiang Province, were scanned by TLS. The tree height, diameter at breast height and diameter at different relative heights of Larix olgensis were extracted from the collected point cloud data. Based on Kozak variable exponential taper equation, a taper equation with local density factor was constructed, and the fitting result was R²adj=0. 935, RMSE=0. 735 6, Bias=0. 869 3. The research showed that: the taper equation model with local density factor had good fitting accuracy, Compared with the traditional Kozak taper equation model and the taper equation model with global density factor, the taper equation model with local density factor had better fitting effect. The calculation range of the local density factor of the Larix olgensis taper equation was positively correlated with tree height and diameter at breast height. The experimental results can provide a theoretical basis for scientific and reasonable timber production in Mengjiagang Forest Farm, and preliminarily reveal the influence of local density factor on the trunk shape of Larix olgensis. [ABSTRACT FROM AUTHOR]

[Objective] Forest health assessment is the basis for forest management. The aims of this study are to conduct forest health assessment, and to provide a certain theoretical basis for achieving sustainable forest management goals. [Methods] This study focused on the widely distributed plantations of Platycladus orientalis, Quercus variabilis, and Robinia pseudoacacia in the southern foothills of the Taihang Mountains. Principal component analysis, cluster analysis, and discriminant analysis were used. Stand productivity, site conditions, community organizational structure, stability and sustainability were selected to evaluate the forest health status, which composed of 21 secondary indicators. [Results Tree height, diameter at breast height, total soil K content and forest fire risk index were the main factors affecting forest health in the study area. Their principal component factor loadings were all greater than 0.6. Among the 17 surveyed plots, 8 plots had a forest health level of healthy' or 'sub healthy' (accounting for 47.0% of the total), while the corresponding forest health levels of Platycladus orientalis, Quercus variabilis, and Robinia pseudoacacia plantations were 60.0%, 33.4%, and 50.0%, respectively. The forest health levels of 9 plots were 'medium healthy' or 'unhealthy' (accounting for 53.0% of the total), and the corresponding forest health levels of Platycladus orientalis, Quercus variabilis, and Robinia pseudoacacia plantations were 40.0%, 66.7%, and 50.0%, respectively. Conclusion Overall, the health status of Platycladus orientalis and Robinia pseudoacacia plantations in the research area is good, while the health status of Quercus variabilis plantations is poor. [ABSTRACT FROM AUTHOR]

Copyright of Chinese Journal of Applied Ecology / Yingyong Shengtai Xuebao is the property of Chinese Journal of Applied Ecology 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 Bulletin of Soil & Water Conservation is the property of Bulletin of Soil & Water Conservation 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.)

【Objective】Through the effects of functional traits of artificial Caragana korshinskii forest on the productivity in the windy-sandy region of northwest Shanxi province, the mechanism of ecological function degradation of artificial C.korshinskii forest was revealed in order to provide theoretical guidance for the sustainability of vegetation management and ecological security in the region.【Method】The effects of plant functional traits on productivity of artificial C.korshinskii forest stand of different ages were studied by general regression model and random forest regression model.【Result】（i）With the increase of stand age, the productivity and aboveground biomass of artificial C.korshinskii forest indicated a trend of increasing first and then decreasing, and the degradation occurred after 18 years;（ii）Artificial C.korshinskii forest stem-leaf ratio（R²=0.277, P=0.000）, branch diameter（R²=0.404, P=0.000）, branch number（R²=0.269, P=0.000）, plant height（R²=0.395, P=0.000）, longitudinal cross-sectional area（R²=0.211, P=0.001）, leaf area（R²=0.314, P=0.000）, leaf carbon content（R²=0.284, P=0.000）, leaf dry weight（R² =0.233, P=0.001）, branch dry weight（R²=0.211, P=0.001） were all extremely significantly positive correlated with productivity.（iii）Stem-leaf ratio（R²=0.287, P=0.000）, longitudinal cross-sectional area（R²=0.318, P=0.000）, leaf dry weight（R²=0.366, P=0.000） and branch dry weight（R²=0.992, P=0.000） were significantly correlated with aboveground biomass, but there was no significant correlation between other functional traits and aboveground biomass（P＞0.05）.（iv）The results of the random forest regression model indicated that stem-leaf ratio（11.59）, branch diameter（9.82）, and branch dry weight（9.18） were the main functional traits that affected its productivity. The branch dry weight（22.59）,leaf dry weight（12.87） and longitudinal cross-sectional area（4.58） were the main functional traits that affected aboveground biomass.【Conclusion】Functional traits related to shoots were one of the main mechanisms affecting the productivity and aboveground biomass of C.korshinskii forest in windy-sandy region of northwest Shanxi province, while the effects of leaf traits were relatively weak. [ABSTRACT FROM AUTHOR]

To explore the stand structure characteristics and development trend of subtropical deciduous-evergreen broadleaf mixed natural forests at a large scale, the 9 hm~2 natural forest stand in Mulinzi Nature Reserve was investigated by measuring tree characteristic values in 2014 and 2019, and the multivariate dynamic characteristics of stand structure were described by analyzing changes in the important values of tree species and the spatial structure parameters uniform angle index (Wi), dominance (Ui), and mingling (Mi). The results showed that the important values of tree species in the 9 hm~2 stand experienced little change, and the horizontal spatial distribution pattern of the whole stand tended to have a gathered distribution after five years of natural growth. The dominance of the whole stand was approximately 0.5, which implied that the natural forest stand had certain advantages and development potential. The forest was mixed well in 2019, as it was five years prior, but the development trend was not significant. The forest is still in the process of succession, and has not reached the level of the natural climax community on the whole. The structure unit was characterized as having absolute dominance, random distribution, and four different tree species (Mi=1.00, Wi=0.50, Ui=0.00) which was more advantageous in the natural forest. In the process of natural forest protection and restoration, to improve forest quality and achieve the ideal state of the spatial structure of the stand, the absolute inferior trees (Mi=0.00, Wi=1.00, Ui=1.00) from the same species in the stand would preferably be subjected to moderate human interference to optimize the stand structure and accurately improve the forest quality. [ABSTRACT FROM AUTHOR]

⑴ Background——Ecological compensation is considered as an important means of ecological improvement, and forest ecological compensation is an important part of ecological compensation in China. Forest ecological compensation is of great significance to improve the enthusiasm of forest ecological builders and maintainers, and to coordinate the interest relationship between the builders of “clear waters and green mountains” and the beneficiaries of “gold and silver mountains”. This paper studies the impact of forest ecological compensation mechanism based on areas on the decisions of forest scales and forest quality inputs made by non-public forest management entities, which can provide a theoretical basis for the policy development and the expansion of compensation scopes.⑵ Methods——The management decision model of public welfare forests management entities under the forest ecological benefit compensation mechanism is established with the forest areas as the key variable, and combined with the examples, the LINGO software is used to analyze the optimal strategies and profits.⑶ Results——There is a positive correlation between the forest scales, forest stock level of the forest management entities and the forest ecological compensation standards. The forest stock per unit area is negatively correlated with the compensation standards. Therefore, under the current compensation standards, the forest ecological benefit compensation mechanism is conducive to promoting the forest management entities to expand the public welfare forest scales, so as to improve the forest stock level and increase their incomes, but it is not conducive to improving the forest quality. The forest areas and forest stock level of the forest management entities are negatively correlated with the financing interest rate, that is, under the same compensation standards, the increase of the loan interest rate is not conducive to the expansion of the forest scale and forest stock level, and will reduce the profits of the forest management entities. The forest areas of the forest management entities is positively correlated with the input cost of forest quality, while the forest stock per unit area and forest stock level are negatively correlated with the input cost of forest quality, that is, with the increase of the input cost of forest quality by the forest management entities, the forest management entities will tend to increase the forest scale and reduce the forest quality, then the forest stock level of the forest management entities decreases, and their profits decrease.⑷ Conclusions and Discussions——On one hand, the ecological benefit compensation mechanism based on forest areas is conducive to improving the enthusiasm of the forest management entities to manage public welfare forests and participate in the creation of forest ecosystem service value, on the other hand, it can improve the total forest stock level and increase forest ecological benefits. However, it still has some limitations in guiding the decision-making of the forest management entities to improve forest quality. Therefore, the implementation of this mechanism will lead the forest management entities to blindly expand the scale of forest management, but ignore the quality of forest management. In order to achieve the goal of high-quality forest development, the following policy suggestions are put forward: First, while providing financial subsidies for the forest management entities, the government can improve the log yields of the forest management entities by providing high-quality saplings, technical support, collective training and other means, so as to help the forest management entities improve the forest quality without expanding the input cost of the forest quality. Second, the government can organize commercial banks to provide green financial credit services for the forest management entities so as to directly reduce the overall cost of forest management. Third, the government should guide the forest management entities to change their management philosophy, help them establish the concept of sustainable management, or expand the non-agricultural income channels of the forest management entities. [ABSTRACT FROM AUTHOR]

Background--With the development of agricultural socialized service organizations, the adoption of agricultural service outsourcing has promoted agricultural production efficiency. However, there is a lack of relevant research in the field of forestry. Whether forestry service outsourcing can improve forestry production efficiency needs further empirical research. Methods--Based on the micro-level survey data of 330 forest farmers in 11 counties of Zhejiang, Fujian and Jiangxi in 2019, 183 economic forest planting households and 204 economic forest plots that have entered the mature stage were selected as the analysis objects, a DEA-Tobit model was constructed to conduct an empirical analysis on the impact of forestry service outsourcing on the forestry production efficiency of economic forest. (3) Results--The average forestry production efficiency of economic forest operators is 0. 41. The overall level is low and there is much room for improvement. There are more low-efficiency economic forest farmers, accounting for 47. 55 %. The low efficiency of economic forest production may be due to the limitation of mountainous terrain and the dispersion of household forest land plots. The average production efficiency of farmers" economic forest in Zhejiang is the highest (0. 43), followed by Jiangxi (0. 41) and Fujian (0. 31). The ratio of forestry service outsourcing expenditure to total household expenditure of economic forest farmers has a positive impact on the production efficiency of economic forest, and is significantly indigenous at the 1 % level. Combined with the theory of induced technological change, economic forest operators as rational economic people, the adoption of service outsourcing will increase capital investment in forestry production, but help to reduce the high labor costs and improve the allocation of family labor, thereby improving the efficiency of forestry production. Overall, the use of service outsourcing is conducive to improving the production efficiency of economic forest. The effect of forestry service outsourcing on economic forest productivity is different in different links. If the forestry service outsourcing is adopted in the tending process, the production efficiency of the farmer's economic forest will increase by 0. 235 units. If the forestry service outsourcing is adopted in the harvesting process, the production efficiency of the farmer's economic forest will increase by 0. 096 units. The adoption of forestry service outsourcing in tending and harvesting has a significant impact on forestry production efficiency, and the promotion effect of tending is greater than that of harvesting. Conclusions and Discussions--The overall economic forest production efficiency of farmers is on the low side, and there is a lot of room for improvement in production efficiency. Farmers have an objective demand for forestry service outsourcing. And service outsourcing is beneficial to improve the production efficiency of economic forest. There are differences in the impact of forestry service outsourcing on the production efficiency of economic forest in different links. To sum up, under the background of promoting agricultural modernization, the overall development trend of forestry service outsourcing is irreversible. Therefore, the support for the fiscal policy of forestry socialized service organizations should be strengthened. On the one hand, the government can formulate and introduce relevant policy documents and incentive schemes. On the other hand, the local government can expand the scope of service outsourcing pilot for forest land, and increase the financial support for forestry socialized service suppliers. It is important to increase the intensity of forest land transfer to promote moderate-scale operation, actively guide and encourage farmers to adopt forestry service outsourcing, and improve the utilization rate of forestry service outsourcing. It is necessary to strengthen the investment in research and development of forestry machinery suitable for mountainous areas, pay attention to the construction of sub-sector service outsourcing system, and lay emphasis on the construction of sub-sector service outsourcing in the construction of service outsourcing system, especially the development of mechanical equipment in the harvesting link. [ABSTRACT FROM AUTHOR]

Water is an important factor in the formation and maintenance of wetland ecosystems. Monitoring the changes in the water area of wetlands is of great significance for wetland conservation. Taking Sentinel - 1A data from 2018 to 2019 as the data source, this study calculated the intra - and inter - annual synthetic aperture radar ( SAR) backscattering coeeficient ( ! ) and coherence coeeficient (" ) images of the Zhalong Wetland. Then, this study aasigned weights according to the proximity to water bodies of color optical images and extracted the weighted images of cr° and ". Finally, this study extracted the wetland water bodies using the threshold segmentation method and random forest algorithm. The purpose is to monitor the dynamic variations in the wetland water area and explore the intra - and inter - annual variation rules of the wetland water body. The results are as follows. The random forest algorithm yielded the highest extraction accuracy of water bodies, with an absolute value of the mean difference of representative months was 6. 69 km2. The threshold segmentation method based on " images yielded the lowest claasification accuracy of water bodies, with an absolute value of the mean diference of 13. 07 km2. Overall, the intra - annual water area of the Zhalong Wetland showed significant seasonal variations during 2018-- 2019. The water area fluctuated in the ranges of 1 300- 1 600 km2 during late spring and early summer and 700 - 900 km2 during late summer and early autumn. The inter - annual water area varied with conditions such as climate and temperature. In particular, the wetland water area in October and November 2019 was approximately 1 050 km2 greater than that in 2018 due to large amounts of rainfall. As shown by the calculation based on effective data, the water area in 2019 was about 550 km2 greater than that in 2018 in the Zhalong Wetland. [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.)

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.)

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.)

Remote sensing is an effective method to assess Light- use Efficiency (LUE) by using Photochemical Reflectance Index (PRI) at leaf level. But when extending this approach to canopy level, we found that the structure of forest canopy is one of the factors that influence the estimation accuracy of LUE. This study calculated the PRI, Normalized Difference Vegetation Index (NDVI), Enhanced Vegetation Index (EVI) and Modified Simple Ratio (MSR) respectively, using the spectral reflection data from the spectro- radiometer at the Dinghu Mountain Forest Ecosystem Research Station in Guangdong, southern China. We compared and analyzed the influence of different canopy structural vegetation indexes (NDVI, EVI and MSR) on PRI used to track LUE as measured by eddy covariance at the canopy level. A multivariate linear regression model was built to improve the fitting accuracy of LUE seasonal dynamics in this subtropical evergreen forest. The results show that: (1) Canopy structural vegetation index of subtropical evergreen forest has a significant correlation with PRI at canopy scale, and the correlation between MSR and PRI was the strongest (R2=0.40, P<0.01); (2) The estimation accuracy of LUE is better when high NDVI and MSR are observed because of larger canopy density and higher LAI; (3) Multivariate regression model between LUE and PRI constructed by NDVI, EVI and MSR improves the estimation accuracy of LUE by 18.14% in the observation period, and 54% from January to May. The LUE estimation method modified by the canopy structure can improve assessment of LUE in the light-use efficiency model, and the ability of remote sensing to accurately assess subtropical evergreen forest productivity. [ABSTRACT FROM AUTHOR]

Early prediction of winter wheat yield is of great significance for the formulation of precise management decisions for the whole growth period of winter wheat. The yield of winter wheat is affected by production technology level and climatic conditions. This study analyzed the feasibility of early prediction of winter wheat yield with long time series meteorological data and random forest method in Henan Province. Based on the ground observation meteorological data and the winter wheat statistical yield data from the year of 1990 to 2015, we extracted 47 climatic factors such as temperature, humidity and precipitation in different growth stages from wheat jointing to heading stage, and 3 spatial factors of latitude, longitude and elevation. A total of 50 parameters were used as a set of feature variables. The actual yield, meteorological yield and relative meteorological yield were used as the target variables respectively, and a random forest yield prediction model with multiple variables was constructed. The data from the year of 1990 to 2009 were used as training samples to construct the model and the forests constructed were validated with data from the year of 2010 to 2015. The yield impact factors were analyzed by combining the data importance results outside the bag. The results showed that: 1) The prediction effect by using meteorological yield and relative meteorological yield as the target variable was better than the yield model. For the meteorological yield and relative meteorological yield models, the determination coefficient R2 was both above 0.8, the mean absolute error (MAE) and root mean square error (RMSE) of meteorological yield were 415 and 558 kg/hm2, respectively, and the MAE and RMSE of relative meteorological yield were 0.07 and 0.09, respectively; 2) The spatial characteristics played an important role in the improving the random forest yield model. On this basis, adding meteorological features improved the prediction accuracy with smaller deviations, higher R2 (0.88), and smaller MAE and RMSE (0.06 and 0.08). The accuracy based on the meteorological features of winter wheat florets differentiation and heading and flowering stage was higher than the other spike differentiation periods, indicating that the environmental changes during this period have a greater impact on the final yield; 3) In the meteorological features, the average temperature and minimum temperature of winter wheat floret differentiation period, the negative accumulated temperature during jointing to heading, and the maximum temperature at heading and flowering stage had great influence on yield. The results of this study provide new ideas and methods for early prediction of winter wheat yield. [ABSTRACT FROM AUTHOR]

The relationship between biodiversity and ecosystem function is one of the hot spot in ecological research. The driving effect of plant diversity on forest productivity has been widely focused, but its underlying mechanisms are still controversial. We explored the impacts of species diversity and phylogenetic diversity on forest productivity at different spatial scales based on a 9 hm 2 forest dynamic monitoring plot of typical mixed broadleaved-Korean pine (Pinus koraiensis) forest in Liangshui National Nature Reserve, Heilongjiang Province, with the censuses data in 2005 and 2015, using linear regression and structural equation models. The results showed that species diversity and phylogenetic diversity were both positively correlated with productivity. The strength of species diversity on productivity gradually enhanced as spatial scales increased, while the effects of phylogenetic diversity on productivity showed opposite trend. On small scales, the effects of phylogenetic diversity on productivity was stronger than species diversity. Moreover, productivity was affected by abiotic factors. Soil factors were significantly positively correlated with productivity at different scales, which was gradually dominated as spatial scales increased. Our results indicated that evolutionary information should be considered in future ecosystem function studies, which might provide additional explanatory power for other diversity metrics. Meanwhile, the effects of spatial scales and abiotic factors should also be considered, which could provide a scientific basis for further understanding the mechanisms underlying the changes of forest productivity.