Due to considerable deforestation in North Korea,there is a need to plan forest restoration programs based on scientific forest management.In this study,a methodology was developed for estimating the site index values...Due to considerable deforestation in North Korea,there is a need to plan forest restoration programs based on scientific forest management.In this study,a methodology was developed for estimating the site index values of six major tree species and the forest productivity potential.The site index values of these tree species were derived in South Korea using the Chapman-Richards equation.These values were used with data from the 6th National Forest Inventory,which included 20 types of edaphic,topographic,and climatic factors,and random forest analysis—a widely used machine learning technique for spatial prediction—to develop a new model for estimating the site index values of these species across South Korea.The prediction accuracy of this model was evaluated using the root mean square error.The results show that the prediction accuracy was high,with a root mean square error of~1m.Moreover,the importance of the variables related to climate and geography was generally high.The proposed site index estimation model for six tree species was applied across North Korea,and its effectiveness tested by comparing the estimated values with those reported in literature from North Korea.The differences between the model outputs and recorded data in the northern alpine regions were presumably due to the lack of data for high-altitude regions in South Korea.This model is based on the determination of the suitability of tree species in restoration efforts.Therefore,it can contribute to the evaluation of forest productivity in North Korea and may help plan efficient forest restoration programs.展开更多
Chinese fir[Cunninghamia lanceolata(Lamb.)Hook.]has a large native distribution range in southern China.Here,we tested differences in productivity of Chinese fir plantations in different climatic regions and screened ...Chinese fir[Cunninghamia lanceolata(Lamb.)Hook.]has a large native distribution range in southern China.Here,we tested differences in productivity of Chinese fir plantations in different climatic regions and screened the main environmental factors affecting site productivity in each region.Relationships of a Chinese fir site index with climatic factors and the soil physiochemical properties of five soil layers were examined in a long-term positioning observation trial comprising a total of 45 permanent plots in Fujian(eastern region in the middle subtropics),Guangxi(south subtropics)and Sichuan(central region in the middle subtropics)in southern China.Linear mixed effects models were developed to predict the site index for Chinese fir,which was found to vary significantly among different climatic regions.Available P,total N,bulk density and total K were dominant predictors of site index in three climatic regions.The regional linear mixed models built using these predictors in the three climatic regions fit well(R~2=0.86–0.97).For the whole study area,the available P in the 0–20-cm soil layer and total N in the 80–100-cm soil layer were the most indicative soil factors.MAP was the most important climatic variable influencing the site index.The model evaluation results showed that the fitting performance and prediction accuracy of the global site index model using the climatic region as the dummy variable and random parameters and the most important soil factors of the three climatic regions as predictors was higher than that of global site index model using the climatic variable and the most indicative soil variables of the whole study area.Our results will help with further evaluation of site quality of Chinese fir plantations and the selection of its appropriate sites in southern China as the climatic changes.展开更多
The determination of site productivity in forest ecosystems plays a crucial role in resource management.This study was carried out to identify relationships between site characteristics and height growth of Corsican m...The determination of site productivity in forest ecosystems plays a crucial role in resource management.This study was carried out to identify relationships between site characteristics and height growth of Corsican maritime pine(Pinus pinaster Ait.)plantations in Turkey.Sixty-nine sample plots>20 years of age were selected from locations with different inclinations,aspects,elevations,slope positions and site class.Soil samples were taken at various depths.Height and age were measured on a dominant tree after felling in each plot.Physical and chemical properties of the soil were determined.Relationships between site index(SI 25)and physiographic factors,climatic attributes as well as soil properties were evaluated using correlation analysis and multiple regression analysis.Site index was significantly related with annual precipitation,mean spring rainfall,rainfall June to September,rainfall of the driest month,length of the dry period,mean maximum temperature,mean temperature of the warmest month,stoniness of the soil,sand,silt,clay,pH,electrical conductivity,and available water capacity.Multiple regression accounted for 57.9%of variations in height growth.The models obtained can be used to determine the site index of potential areas in Turkey for maritime pine.It can be said that the productivity of maritime pine may decline in the future due to global climate change.展开更多
Determination of site quality is a basic tool for proper selection of locations and species, in management of forest plantations.Throughout the Caribbean studies of site quality are few and are hampered by statistical...Determination of site quality is a basic tool for proper selection of locations and species, in management of forest plantations.Throughout the Caribbean studies of site quality are few and are hampered by statistical limitations, inappropriate growth models, and limited data. We fitted growth curves for dominant height to evaluate and classify site quality of teak (Tectona grandis) plantations by using data from 44 permanent sample plots established since 1990 in 3 22 years old teak plantations in the Colombian Caribbean region. We used Korf’s and von Bertalanffy’s models to fit curves as nonlinear effects models. Both models, with a single random parameter, were considered as adequate for dominant height growth modelling, but Korf’s model was superior. There sulting curves were anamorphic and closely reflected high variability insite quality. Five site classes were clarified: at a base age of 12 years old,teak reached a mean dominant height of 24.8 m on the best sites, 9.8 m inthe worst sites, and in the averages sites, 15.8-18.8 m. Using this model,we identified the best and the worst sites for teak plantations in the Caribbean region. This model proved a useful tool, not only for site quality evaluation, but also for improved teak plantation planning and management.展开更多
According to the growth characteristics of natural Korean pine (Pinus Koraiensis) forests, 6 equations such as Chapman-Richards equation, Logistic equation, Power equation, and so on were selected to ftt for the growt...According to the growth characteristics of natural Korean pine (Pinus Koraiensis) forests, 6 equations such as Chapman-Richards equation, Logistic equation, Power equation, and so on were selected to ftt for the growth modeIs for Korean pine forest. The growth models were developed based on 208 random trees and 24o dominant trees. Results show that the Chapman-Richards equation is the best model for estimating tree height by age and DBH, while the Parabola equation is fittest for predicting DBH by age or estimating age from DBH. The site index table of Korean pine forest was compiled by using the proportional method with the Chapman-Richards equation as the guide curve and vaIidated by accuracy test.展开更多
Based upon 3 widely used base models, a total of 8 ADA/GADA site index models were derived.The data for these models in this study were obtained from 79 pith-split stem analysis plots and the estimation method was &qu...Based upon 3 widely used base models, a total of 8 ADA/GADA site index models were derived.The data for these models in this study were obtained from 79 pith-split stem analysis plots and the estimation method was "indicator variable approach".We used both fit statistics and visual analysis to select the best-fit model,and attached more importance to the visual analysis.A comprehensive application analysis was also given to the selected model.The results showed:1) GADA outperformed ADA with respect to predictions.2) A GADA model derived from HossfeldⅣpresented the best prediction ability.It was suggested that the model be used to predict dominant height and to estimate site index for ponderosa pine stands ranging 30 -200 years in British Columbia,Canada.3) The best site index age was age of 100 years,based upon relative errors of predictions.展开更多
Turkish red pine is an important forest tree species because of its role in the ecosystem whose range includes many countries in the eastern Mediterranean basin.In addition,red pine is a preferred forest tree species ...Turkish red pine is an important forest tree species because of its role in the ecosystem whose range includes many countries in the eastern Mediterranean basin.In addition,red pine is a preferred forest tree species due to rapid growth,usage in afforestation in arid areas and the production of non-wood forest products such as resin.The aim of the study was to examine the relationship between the productivity of red pine and ecosystem in the lower and middle belt of the Taurus Mountains,and to determine the interrelations between the productivity of red pine and ecosystem.Multivariate analyses(multiple regression analysis and artificial neural networks)were used to model the efficiency(biomass production)of red pine.From the multivariate analyses,a productivity model of the species was created with the slope,soil depth,and precipitation in the driest variables.A significant correlation was found between site index and site factors in the driest quarter.These variables had a statistically significant relationship with the site index in the multiple regression analysis.The forecast power of the model was 0.33.Of the methods used,the artificial neural network consisting of 2 L10 N(2 Layers 10 Neurons)had the highest margin of explanation(R^(2)=0.71)and the lowest margin of error.This model has the potential to open land aimed for afforestation studies with red pine in forestry areas.The results will shed light on afforestation studies to be carried out in the Western Mediterranean region and in similar ecosystems.展开更多
基于决策实验室分析法(Decision Making Trial and Evaluation Laboratory,DEMA-TEL)和解释结构模型(Interpretative Structural Modeling Method,ISM)构建了装备保障中心选址问题评价指标体系。在确定的14种装备保障中心选址问题考虑...基于决策实验室分析法(Decision Making Trial and Evaluation Laboratory,DEMA-TEL)和解释结构模型(Interpretative Structural Modeling Method,ISM)构建了装备保障中心选址问题评价指标体系。在确定的14种装备保障中心选址问题考虑因素中,首先利用DEMATEL模型分析各评价指标间的因果关系和影响程度,并将所有指标划分为3层;再通过ISM法则构建多级有向拓扑图,进一步评估了各指标之间的关系,并得到3级评价体系。研究结果表明:与已有研究相比,本文方法可揭示各影响因素之间的内在联系与结构关系;对于装备保障中心选址问题,需要对其直接因素、中间因素和深层因素进行综合考虑,其中,气象条件、交通运输条件、信息化水平、隐蔽及伪装条件、受敌威胁程度等是所有指标中的关键因素,应予以重点关注。展开更多
In this study height growth models for hybrid aspen were developed using three growth equations.The mean age of the hybrid aspen was 21 years(range 15 51 years) with a mean stand density of 946stems ha-1(87 2374) and ...In this study height growth models for hybrid aspen were developed using three growth equations.The mean age of the hybrid aspen was 21 years(range 15 51 years) with a mean stand density of 946stems ha-1(87 2374) and a mean diameter at breast height(over bark) of19.6 cm(8.5 40.8 cm).Site index was also examined in relation to soil type.Multiple samples were collected for three types of soil: light clay,medium clay and till.Site index curves were constructed using the collected data and compared with published reports.A number of dynamic equations were assessed for modeling top-height growth from total age.A Generalized Algebraic Difference Approach model derived by Cieszewski(2001) performed the best.This model explained 99% of the observed variation in tree height growth and exhibited no apparent bias across the range of predicted site indices.There were no significant differences between the soil types and site indices.展开更多
基金supported by the National Institute of Forest Science(Project No.FM0800-2019-05)。
文摘Due to considerable deforestation in North Korea,there is a need to plan forest restoration programs based on scientific forest management.In this study,a methodology was developed for estimating the site index values of six major tree species and the forest productivity potential.The site index values of these tree species were derived in South Korea using the Chapman-Richards equation.These values were used with data from the 6th National Forest Inventory,which included 20 types of edaphic,topographic,and climatic factors,and random forest analysis—a widely used machine learning technique for spatial prediction—to develop a new model for estimating the site index values of these species across South Korea.The prediction accuracy of this model was evaluated using the root mean square error.The results show that the prediction accuracy was high,with a root mean square error of~1m.Moreover,the importance of the variables related to climate and geography was generally high.The proposed site index estimation model for six tree species was applied across North Korea,and its effectiveness tested by comparing the estimated values with those reported in literature from North Korea.The differences between the model outputs and recorded data in the northern alpine regions were presumably due to the lack of data for high-altitude regions in South Korea.This model is based on the determination of the suitability of tree species in restoration efforts.Therefore,it can contribute to the evaluation of forest productivity in North Korea and may help plan efficient forest restoration programs.
基金supported financially by Research on Directional Cultivation Technology of Cunninghamia lanceolata Timber Forest programthe National Key R&D Program of the 14th Five Year Plan(Grant Number 2021YFD2201301)。
文摘Chinese fir[Cunninghamia lanceolata(Lamb.)Hook.]has a large native distribution range in southern China.Here,we tested differences in productivity of Chinese fir plantations in different climatic regions and screened the main environmental factors affecting site productivity in each region.Relationships of a Chinese fir site index with climatic factors and the soil physiochemical properties of five soil layers were examined in a long-term positioning observation trial comprising a total of 45 permanent plots in Fujian(eastern region in the middle subtropics),Guangxi(south subtropics)and Sichuan(central region in the middle subtropics)in southern China.Linear mixed effects models were developed to predict the site index for Chinese fir,which was found to vary significantly among different climatic regions.Available P,total N,bulk density and total K were dominant predictors of site index in three climatic regions.The regional linear mixed models built using these predictors in the three climatic regions fit well(R~2=0.86–0.97).For the whole study area,the available P in the 0–20-cm soil layer and total N in the 80–100-cm soil layer were the most indicative soil factors.MAP was the most important climatic variable influencing the site index.The model evaluation results showed that the fitting performance and prediction accuracy of the global site index model using the climatic region as the dummy variable and random parameters and the most important soil factors of the three climatic regions as predictors was higher than that of global site index model using the climatic variable and the most indicative soil variables of the whole study area.Our results will help with further evaluation of site quality of Chinese fir plantations and the selection of its appropriate sites in southern China as the climatic changes.
基金funded by the Turkish General Directorate of Forestry as part of the project“Relationship between growth of maritime pine(Pinus pinaster Ait.)plantations and site characteristics in Turkey[ESK‒27(6319)]”.
文摘The determination of site productivity in forest ecosystems plays a crucial role in resource management.This study was carried out to identify relationships between site characteristics and height growth of Corsican maritime pine(Pinus pinaster Ait.)plantations in Turkey.Sixty-nine sample plots>20 years of age were selected from locations with different inclinations,aspects,elevations,slope positions and site class.Soil samples were taken at various depths.Height and age were measured on a dominant tree after felling in each plot.Physical and chemical properties of the soil were determined.Relationships between site index(SI 25)and physiographic factors,climatic attributes as well as soil properties were evaluated using correlation analysis and multiple regression analysis.Site index was significantly related with annual precipitation,mean spring rainfall,rainfall June to September,rainfall of the driest month,length of the dry period,mean maximum temperature,mean temperature of the warmest month,stoniness of the soil,sand,silt,clay,pH,electrical conductivity,and available water capacity.Multiple regression accounted for 57.9%of variations in height growth.The models obtained can be used to determine the site index of potential areas in Turkey for maritime pine.It can be said that the productivity of maritime pine may decline in the future due to global climate change.
基金Reforestadora del Caribe S.A and the DIME (Research Direction of the National University of Colombia, Medellin Branch) for providing the funds for this project
文摘Determination of site quality is a basic tool for proper selection of locations and species, in management of forest plantations.Throughout the Caribbean studies of site quality are few and are hampered by statistical limitations, inappropriate growth models, and limited data. We fitted growth curves for dominant height to evaluate and classify site quality of teak (Tectona grandis) plantations by using data from 44 permanent sample plots established since 1990 in 3 22 years old teak plantations in the Colombian Caribbean region. We used Korf’s and von Bertalanffy’s models to fit curves as nonlinear effects models. Both models, with a single random parameter, were considered as adequate for dominant height growth modelling, but Korf’s model was superior. There sulting curves were anamorphic and closely reflected high variability insite quality. Five site classes were clarified: at a base age of 12 years old,teak reached a mean dominant height of 24.8 m on the best sites, 9.8 m inthe worst sites, and in the averages sites, 15.8-18.8 m. Using this model,we identified the best and the worst sites for teak plantations in the Caribbean region. This model proved a useful tool, not only for site quality evaluation, but also for improved teak plantation planning and management.
文摘According to the growth characteristics of natural Korean pine (Pinus Koraiensis) forests, 6 equations such as Chapman-Richards equation, Logistic equation, Power equation, and so on were selected to ftt for the growth modeIs for Korean pine forest. The growth models were developed based on 208 random trees and 24o dominant trees. Results show that the Chapman-Richards equation is the best model for estimating tree height by age and DBH, while the Parabola equation is fittest for predicting DBH by age or estimating age from DBH. The site index table of Korean pine forest was compiled by using the proportional method with the Chapman-Richards equation as the guide curve and vaIidated by accuracy test.
文摘Based upon 3 widely used base models, a total of 8 ADA/GADA site index models were derived.The data for these models in this study were obtained from 79 pith-split stem analysis plots and the estimation method was "indicator variable approach".We used both fit statistics and visual analysis to select the best-fit model,and attached more importance to the visual analysis.A comprehensive application analysis was also given to the selected model.The results showed:1) GADA outperformed ADA with respect to predictions.2) A GADA model derived from HossfeldⅣpresented the best prediction ability.It was suggested that the model be used to predict dominant height and to estimate site index for ponderosa pine stands ranging 30 -200 years in British Columbia,Canada.3) The best site index age was age of 100 years,based upon relative errors of predictions.
基金supported by Forestry Department of Yenisarbademli Vocational School(Isparta University of Applied Sciences)。
文摘Turkish red pine is an important forest tree species because of its role in the ecosystem whose range includes many countries in the eastern Mediterranean basin.In addition,red pine is a preferred forest tree species due to rapid growth,usage in afforestation in arid areas and the production of non-wood forest products such as resin.The aim of the study was to examine the relationship between the productivity of red pine and ecosystem in the lower and middle belt of the Taurus Mountains,and to determine the interrelations between the productivity of red pine and ecosystem.Multivariate analyses(multiple regression analysis and artificial neural networks)were used to model the efficiency(biomass production)of red pine.From the multivariate analyses,a productivity model of the species was created with the slope,soil depth,and precipitation in the driest variables.A significant correlation was found between site index and site factors in the driest quarter.These variables had a statistically significant relationship with the site index in the multiple regression analysis.The forecast power of the model was 0.33.Of the methods used,the artificial neural network consisting of 2 L10 N(2 Layers 10 Neurons)had the highest margin of explanation(R^(2)=0.71)and the lowest margin of error.This model has the potential to open land aimed for afforestation studies with red pine in forestry areas.The results will shed light on afforestation studies to be carried out in the Western Mediterranean region and in similar ecosystems.
文摘基于决策实验室分析法(Decision Making Trial and Evaluation Laboratory,DEMA-TEL)和解释结构模型(Interpretative Structural Modeling Method,ISM)构建了装备保障中心选址问题评价指标体系。在确定的14种装备保障中心选址问题考虑因素中,首先利用DEMATEL模型分析各评价指标间的因果关系和影响程度,并将所有指标划分为3层;再通过ISM法则构建多级有向拓扑图,进一步评估了各指标之间的关系,并得到3级评价体系。研究结果表明:与已有研究相比,本文方法可揭示各影响因素之间的内在联系与结构关系;对于装备保障中心选址问题,需要对其直接因素、中间因素和深层因素进行综合考虑,其中,气象条件、交通运输条件、信息化水平、隐蔽及伪装条件、受敌威胁程度等是所有指标中的关键因素,应予以重点关注。
基金Foundation project： This paper was supported by China Postdoctoral Science Foundation （2005037637）, Heilongjiang Postdoctoral Science Foundation （LBH-Z05031） and Project of State Forestry Administration, China （2006-37）.
文摘阴谋采样在 Larix olgensisin Heilongjiang 省的第二个耕作区域被进行，中国。由在 L 的工业种植园分析 840 个阴谋和 248 棵样品树的阴谋调查数据，木头性质，和牛皮纸肉。不同地点上的 olgensis，我们检验了 L 的生长过程。olgensis 有合适的结构，木纤维特征，化学组成，物理表演和肉特征的工业种植园。地点条件在种植园生长上有主要效果，这被建议，纤维包含，纤维长度，在纤维长度之间的率和纤维宽度， pulping 率和肉物理紧张。为 L 的最好的地点。工业种植园生长是的 olgensis 地点班Ⅰ和地点班Ⅱ，它在上降低地点。地点状况在木头特征上有明显的影响。在学习的地点条件和看台密度的范围以内，更坏地点条件，纤维包含越少，越 shorter，并且越多纤维长度 1% NaOH 抽取。当看台年龄增加，这种关系变得更明显。然而， pulping 率和肉物理紧张上的地点状况的影响不是明显的。结果为 L 的工业纤维种植园的耕作提供理论底。olgensis。
文摘In this study height growth models for hybrid aspen were developed using three growth equations.The mean age of the hybrid aspen was 21 years(range 15 51 years) with a mean stand density of 946stems ha-1(87 2374) and a mean diameter at breast height(over bark) of19.6 cm(8.5 40.8 cm).Site index was also examined in relation to soil type.Multiple samples were collected for three types of soil: light clay,medium clay and till.Site index curves were constructed using the collected data and compared with published reports.A number of dynamic equations were assessed for modeling top-height growth from total age.A Generalized Algebraic Difference Approach model derived by Cieszewski(2001) performed the best.This model explained 99% of the observed variation in tree height growth and exhibited no apparent bias across the range of predicted site indices.There were no significant differences between the soil types and site indices.
