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Tree diameter distribution models are important tools for forest management decision making. Soil variables affect tree growth and thus diameter distribution. However, few studies have been conducted on diameter distribution models describing the effects of soil. This study developed a soil-sensitive diameter distribution model based on 213 sample plots of Larix principis-rupprechtii plantations in northern China. The Weibull distribution model was modified by a compatible simultaneous system and the percentile method with the inclusion of soil variables. The most significant factors influencing the diameter distribution of L. principis-rupprechtii in terms of both scale and shape were stand characteristics and available K and alkali-hydrolysable N. The adjusted coefficient of determination for parameter γ significantly improved by 16.0%, while the root mean square error for parameter β decreased by 10.4%. The F test indicated a substantial difference between the models with and without soil variables. From the perspective of adjustable R2 values, the Akaike information criterion, root mean square error, relative error index, and absolute error index, the inclusion of stand and soil factors in the tree diameter distribution model enhanced its performance compared to the model that did not consider soil factors. The soil-sensitive diameter distribution model is proven to be effective and accurate. [ABSTRACT FROM AUTHOR]

Land use/land cover change has a significant indicative effect on the carbon storage of terrestrial ecosystems. We selected Chang-Zhu-Tan urban agglomeration as the research object, coupled FLUS and InVEST models to explore the changes in land use and carbon storage in the region from 2010 to 2020, and predicted their spatiotemporal evolution characteristics under three scenarios in 2035: natural development (S1), ecological development priority (S2) and urban development priority (S3). Spatial autocorrelation was used to analyze the spatial distribution of carbon storage. The results revealed a rapid urban expansion encroaching on cultivated land and forest from 2010 to 2020, resulting in a total urban area of 1957.50 km2 by 2020. Carbon storage experienced a total loss of 6.86 × 106 t, primarily between 2010 and 2015. The InVEST model indicated a spatial distribution in a pattern of "low in the middle and high around", with areas of low carbon storage showing large-scale faceted aggregate distribution by 2035. Under different regional development scenarios, the S3 exhibited the highest carbon storage loss, reaching 150.93 × 106 t. The S1 experienced a decline of 136.30 × 106 t, while the S2 only experienced a reduction of 24.26 × 106 t. The primary driving factor of carbon storage reduction is the conversion of forest and cultivated land into urban areas. It is recommended that the implementation of regional ecological protection policies and the optimization of land use structures effectively minimize the loss of carbon storage. [ABSTRACT FROM AUTHOR]

With the changing demands imposed on forests by human beings, optimizing forest management to fully utilize their multifunctionality has become a priority. Reasonable forest management measures can maintain stable forest ecosystems that fully coordinate the balance between ecological, societal, and economic aspects. As planted forests are the main application scenario of forest management worldwide, it is of great importance to understand the trade-offs between ecosystem functions and their dynamic changes in planted forests. This paper investigates the effects of different management measures on the ecosystem function of Pinus massoniana plantation forests in the subtropics. It examines four different management measures and explores how they impact multiple ecosystem function indexes and the trade-offs between ecosystem functions during forest restoration. The different management measures effectively promoted the studied ecosystem functions, with higher annual growth rates of the integrated functional indices for timber production, carbon sequestration, and biodiversity compared to the control. Over time, the ecosystem function interactions under the different management measures alternated between trade-offs and synergistic. Only the stand with a 65% harvesting intensity and replanting of various native broadleaf species was able to sustain the synergistic relationships among ecosystem functions, and the dominant function trended toward biodiversity. These observations of dynamic changes and interactions in ecosystem functions of Pinus massoniana plantation forests under various management measures will serve as a valuable reference for the sustainable management of these forests in subtropical regions. [ABSTRACT FROM AUTHOR]

Stand dominant height has a close relationship with stand productivity and is not much affected by stand density and thinning within a reasonable density range, making it an excellent indicator for estimating stand site quality. Topographic factors (altitude, aspect, slope, etc.) have a significant influence on the growth process of stand level, and the combination of different site factors increases the randomness of the evaluation of forest productivity. In this paper, with one-way ANOVA, it was determined that the effects of density and management mode on the Masson pine stand dominant height were not significant. The data on the Masson pine stand dominant height in the southern subtropics in Guangxi, China, were analyzed, and the GADA model was established using the nonlinear least squares method, the Bayesian approach, and the one-level nonlinear mixed-effects model with the topographic factor as the random effect, respectively. The results indicated that the nonlinear mixed-effects model had the best fitting performance and the highest prediction accuracy for stand site quality (a 0.27% improvement in R² compared to the least squares method and a 1.30% improvement in R² compared to the Bayesian approach), while the model obtained by the Bayesian approach had more elasticity and biological significance. In summary, when the data distribution is uniform and comprehensive, introducing terrain factors into the establishment of site index models can provide a more scientific basis for estimating the productivity of southern subtropical Masson pine stands under different site conditions. When the data distribution is uneven, applying the Bayesian approach can make the site index model more biologically meaningful. The stand site quality model can predict the potential production capacity of forests, which is an important basis and can support forest management and harvest prediction. The results of this study provide a theoretical and practical basis for the establishment of a reasonable site index model for the Masson pine stand. [ABSTRACT FROM AUTHOR]

Robots are now widely used in product disassembly lines, which significantly improves end-of-life (EOL) product disassembly efficiency. Most of the current research on disassembly line balancing problems focuses on decomposing one product. More than one product can be disassembled concurrently, which can further improve the efficiency. Moreover, uncertainty such as the depreciation of EOL products, may result in disassembly failure. In this research, a stochastic multi-product robotic disassembly line balancing model is established using an AND/OR graph. It takes the precedence relationship, cycle constraint, and disassembly failure into consideration to maximize the profit and minimize the energy consumption for disassembling multiple products. A Pareto-improved multi-objective brainstorming optimization algorithm combined with stochastic simulation is proposed to solve the problem. Furthermore, by conducting experiments on some real cases and comparing with four state-of-the-art multi-objective optimization algorithms, i.e., the multi-objective discrete gray wolf optimizer, artificial bee colony algorithm, nondominated sorting genetic algorithm II, and multi-objective evolutionary algorithm based on decomposition, this paper validates its excellent performance in solving the concerned problem. [ABSTRACT FROM AUTHOR]

The nitrogen isotope composition of plants (δ15N) can comprehensively reflect information on climate change and ecosystems' nitrogen cycle. By collecting common herbs and soil samples along the 400 mm isoline of mean annual precipitation (MAP) in the agro-pastoral zone of North China (APZNC) and measuring their δ15N values, the statistical characteristics of foliar δ15N of herbs and the responses of foliar δ15N to the MAP and mean annual temperature (MAT) were analyzed. The results showed that: (1) the δ15N values of all herbs investigated varied from −5.5% to 15.25%. Among them, the δ15N value range of C3 herbs (−5.5~15.00%) was wider than that of C4 herbs (−2.17~15.25%), but the average value (3.27%) of C3 herbs was significantly lower than that of C4 herbaceous plants (5.55%). This difference provides an important method for identifying plants of different photosynthetic types by nitrogen isotope technology. (2) Along the transect from northeast to southwest, the δ15N of both C3 and C4 herbs decreased with the increase in the MAP, but not significantly for C3 herbs. The inverse relationship between the nitrogen isotopic signatures of herbs and MAP is consistent with previous studies. However, the MAP in the APZNC is found to only explain a small amount of the observed variance in the δ15N herbs (C3 herbs: 10.40%; C4 herbs: 25.03%). (3) A strong negative relationship was found between δ15N of herbs and MAT across the transect (C3 herbs: −0.368%/°C; C4 herbs: −0.381%/°C), which was contrary to the global pattern and some regional patterns. There was no significant difference in the δ15N responses of two different photosynthetic herbs to temperature, but the effect of temperature on the variances of δ15N of C3 and C4 herbs was significantly greater than that of precipitation. This suggests that temperature is a key factor affecting foliar δ15N of herbs in this transect. The above findings may be of value to global change researchers studying the processes of the nitrogen cycle and gaining an insight into climate dynamics of the past. [ABSTRACT FROM AUTHOR]

In order to understand forest services at stand level through the integration of structural attributes, forest structures in three main stand types were analyzed based on various structural attributes relating to the services of habitat conservation, timber production and soil water conservation in Loess Plateau, China. Forty sample plots with similar site and environment conditions were established in three types of oak stands. Twenty-two indexes such as stand density, mean DBH, mean height, etc., were selected to analyze the relationship between structural attributes and forest service. With a core set of structural attributes selected by principal component analysis, the link between the service and structural attributes and the compatibility between each service was analyzed using correlation analysis. The results show that the oak–broadleaf mixed forest has the highest structural complexity index (SCI), indicating the best habitat conservation among others, while the oak–pine mixed forest and pure oak forest have the highest timber value in different scenarios of timber price, indicating the largest potential for timber production. Little differences were found between stand types regarding the indicators for soil water conservation. The structural attributes that had a positive correlation with habitat conservation (e.g., number of shrub species, species richness of canopy layer, the proportion of broadleaves and snag density) were identified to be negative for timber production; while the attributes that had a positive correlation with timber production (e.g., stand density and proportion of pine and oaks) were found to be negative for habitat conservation. The results of the trade-off analysis showed that timber production tends to be conflicting with the other two non-timber forest services. In order to enhance the provisioning of multiple services, it was suggested to implement the interventions that could balance these services, such as structural retention and single-tree selective logging. This study could contribute to the theoretical base for the decision making in the multi-purpose sustainable management of oak forests in China. [ABSTRACT FROM AUTHOR]

As the dominant height of the stand at the baseline age, the site index is an important index to evaluate site quality. However, due to the variability of environmental factors, the growth process of the dominant height of the same tree species was variable in different regions which influenced the estimation results of the site index. In this study, a methodology that established site index modeling of larch plantations with site types as a random effect in northern China was proposed. Based on 394 sample plots, nine common base models were developed, and the best model (M8) was selected (R2 = 0.5773) as the base model. Moreover, elevation, aspect, and slope position were the main site factors influencing stand dominant height through the random forest method. Then, the three site factors and their combinations (site types) were selected as random effects and simulated by the nonlinear mixed-effects model based on the model M8. The R2 values had raised from 0.5773 to 0.8678, and the model with combinations (94 kinds) of three site factors had the best performance (R2 = 0.8678). Considering the model accuracy and practical application, the 94 combinations were divided into three groups of site types (3, 5, and 8) by hierarchical clustering. Furthermore, a mixed-effects model considering the random effects of these three groups was established. All the three groups of site types got a better fitting effect (groups 3 R2 = 0.8333, groups 5 R2 = 0.8616, groups 8 R2 = 0.8683), and a better predictive performance (groups 3 R2 = 0.8157, groups 5 R2 = 0.8464, groups 8 R2 = 0.8479 for 20 percent of plots randomly selected per group in the calibration procedure) using the leave-one-out cross-validation approach. Therefore, groups 5 of site types had better applicability and estimation of forest productivity at the regional level and management plan design. [ABSTRACT FROM AUTHOR]

Determining differences in regional carbon emissions and the factors that affect these differences is important in the realization of differentiated emissions mitigation policies. This paper adopts the Theil index and the partial least square-variable importance of projection (PLS-VIP) method to analyze the change characteristics, regional differences and causes of carbon emissions, as well as the extent to which various factors influenced carbon emissions in China's eight economic regions in 2005–2017. The results indicate that (1) during the study period, carbon emissions in the eight economic regions displayed a rigid uptrend with a phased characteristic. The growth rates of carbon emissions were different across the studied regions. (2) The overall difference in regional carbon emissions showed an increasing trend, mainly owing to increasing interregional differences. (3) The extent of the influence and explanatory ability of each factor on regional carbon emissions and discrepancies in carbon emissions were different. Population size, economic development, and energy intensity were found to be the three main factors influencing regional carbon emission changes. Industrial structure and urbanization were also contributors to regional differences in emissions. The influence of energy structure on regional carbon emissions and its explanatory power were weak on the whole, but its elastic coefficients and VIP values changed significantly. Finally, regionally targeted proposals for emissions mitigation are offered. [ABSTRACT FROM AUTHOR]

The risk assessment of environmental conflicts has been an integral part of measuring the operability of projects as well as the happiness of the affected population. With the current situation of environmental crises, environmental conflict has an effect on society. In order to maintain the stable development of society, we used the fuzzy comprehensive evaluation method and the analytic hierarchy process to study the risk of a population being affected by a project producing environmental pollution. Furthermore, we provided an approach that had the potential to quantify as well as give a risk assessment of the environmental impact. The results classified 0.397, 0.202, and 0.295 as medium, relatively high, and highest risk, respectively. We deemed that the conflict mode between people, government, and enterprise is actually the confrontation between benefit gainers and benefit losers to a great extent. In subtle ways, this conflict mode has several roles. The solution of environmental conflicts lies in how the roles of government and enterprises change and how the interests of the public are considered. Environmental risks can be safely mitigated without violence by managing relationships between people, governments and businesses. [ABSTRACT FROM AUTHOR]

With the advancement of urbanization, the harm caused to human health by PM 2.5 pollution has been receiving increasing attention worldwide. In order to increase public awareness and understanding of the damage caused by PM 2.5 in the air and gain the attention of relevant management departments, Changsha City is used as the research object, and the environmental quality data and public health data of Changsha City from 2013 to 2017 are used. All-cause death, respiratory death, cardiovascular death, chronic bronchitis, and asthma were selected as the endpoints of PM 2.5 pollution health effects, according to an exposure-response coefficient, Poisson regression model, and health-impact-assessment-related methods (the Human Capital Approach, the Willingness to Pay Approach, and the Cost of Illness Approach), assessing the health loss and economic loss associated with PM 2.5 . The results show that the pollution of PM 2.5 in Changsha City is serious, which has resulted in extensive health hazards and economic losses to local residents. From 2013 to 2017, when annual average PM 2.5 concentrations fell to 10 μg/m 3 , the total annual losses from the five health-effect endpoints were $2788.41 million, $2123.18 million, $1657.29 million, $1402.90 million, and $1419.92 million, respectively. The proportion of Gross Domestic Product (GDP) in the current year was 2.69%, 1.87%, 1.34%, 1.04% and 0.93%, respectively. Furthermore, when the concentration of PM 2.5 in Changsha City drops to the safety threshold of 10 μg/m 3 , the number of affected populations and health economic losses can far exceed the situation when it falls to 35 μg/m 3 , as stipulated by the national secondary standard. From 2013 to 2017, the total loss under the former situation was 1.48 times, 1.54 times, 1.86 times, 2.25 times, and 2.33 times that of the latter, respectively. Among them, all-cause death and cardiovascular death are the main sources of health loss. Taking 2017 as an example, when the annual average concentration dropped to 10 μg/m 3 , the health loss caused by deaths from all-cause death and cardiovascular disease was 49.16% of the total loss and 35.73%, respectively. Additionally, deaths as a result of respiratory disease, asthma, and chronic bronchitis contributed to 7.31%, 7.29%, and 0.51% of the total loss, respectively. The research results can provide a reference for the formulation of air pollution control policies based on health effects, which is of great significance for controlling air pollution and protecting people's health.