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A Pragmatic Analysis of Public Signs in Chinese-English Translation——Based on the Example of Shaoguan National Forest Park
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作者 吕海霞 冯诗雅 《海外英语》 2018年第20期81-83,共3页
With the rapid development of economy and close international exchanges, the English translation of public signs is in-creasingly important and cannot be ignored. This paper takes Shaoguan National Forest Park as an e... With the rapid development of economy and close international exchanges, the English translation of public signs is in-creasingly important and cannot be ignored. This paper takes Shaoguan National Forest Park as an example to analyze its publicsigns translation and points out some pragmatic failures from two aspects:pragmatic language failures and social pragmatic failures.Also, the paper puts forward some suggestions based on the translation error analysis. 展开更多
关键词 public signs Shaoguan national forest Park TRANSLATION pragmatic failures
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The national forest inventory in China:history-results-international context 被引量:8
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作者 Wei Sheng Zeng Erkki Tomppo +1 位作者 Sean P.Healey Klaus V.Gadow 《Forest Ecosystems》 SCIE CSCD 2015年第4期288-303,共16页
Background: National forest resource assessments Inventories (NFI's), constitute an important nationa and monitoring, commonly known as National Forest information infrastructure in many countries. Methods: This ... Background: National forest resource assessments Inventories (NFI's), constitute an important nationa and monitoring, commonly known as National Forest information infrastructure in many countries. Methods: This study presents details about developments of the NFI in China, including sampling and plot design and the uses of alternative data sources, and specifically · reviews the evolution of the national forest inventory in China through the 20th and 21st centuries, with some reference to Europe and the US; · highlights the emergence of some common international themes: consistency of measurement; sampling designs; implementation of improved technology; expansion of the variables monitored more efficient scientific transparency;· presents an example of how China's expanding NFI exemplifies these global trends. Results: Main results and important changes in China's NFI are documented, both to support continued trend analysis and to provide data users with historical perspective. Conclusions: New technologies and data needs ensure that the Chinese NFI, like the national inventories in other countries, will continue to evolve. Within the context of historical change and current conditions, likely directions for this evolution are suggested. 展开更多
关键词 China EUROPE USA national forest inventories forest inventory and analysis
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Comparison of the local pivotal method and systematic sampling for national forest inventories
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作者 Minna Räty Mikko Kuronen +3 位作者 Mari Myllymäki Annika Kangas Kai Mäkisara Juha Heikkinen 《Forest Ecosystems》 SCIE CSCD 2020年第4期716-732,共17页
Background:The local pivotal method(LPM)utilizing auxiliary data in sample selection has recently been proposed as a sampling method for national forest inventories(NFIs).Its performance compared to simple random samp... Background:The local pivotal method(LPM)utilizing auxiliary data in sample selection has recently been proposed as a sampling method for national forest inventories(NFIs).Its performance compared to simple random sampling(SRS)and LPM with geographical coordinates has produced promising results in simulation studies.In this simulation study we compared all these sampling methods to systematic sampling.The LPM samples were selected solely using the coordinates(LPMxy)or,in addition to that,auxiliary remote sensing-based forest variables(RS variables).We utilized field measurement data(NFI-field)and Multi-Source NFI(MS-NFI)maps as target data,and independent MS-NFI maps as auxiliary data.The designs were compared using relative efficiency(RE);a ratio of mean squared errors of the reference sampling design against the studied design.Applying a method in NFI also requires a proven estimator for the variance.Therefore,three different variance estimators were evaluated against the empirical variance of replications:1)an estimator corresponding to SRS;2)a Grafström-Schelin estimator repurposed for LPM;and 3)a Matérn estimator applied in the Finnish NFI for systematic sampling design.Results:The LPMxy was nearly comparable with the systematic design for the most target variables.The REs of the LPM designs utilizing auxiliary data compared to the systematic design varied between 0.74–1.18,according to the studied target variable.The SRS estimator for variance was expectedly the most biased and conservative estimator.Similarly,the Grafström-Schelin estimator gave overestimates in the case of LPMxy.When the RS variables were utilized as auxiliary data,the Grafström-Schelin estimates tended to underestimate the empirical variance.In systematic sampling the Matérn and Grafström-Schelin estimators performed for practical purposes equally.Conclusions:LPM optimized for a specific variable tended to be more efficient than systematic sampling,but all of the considered LPM designs were less efficient than the systematic sampling design for some target variables.The Grafström-Schelin estimator could be used as such with LPMxy or instead of the Matérn estimator in systematic sampling.Further studies of the variance estimators are needed if other auxiliary variables are to be used in LPM. 展开更多
关键词 Auxiliary data Bias Local pivotal method Matérn estimator national forest inventory Sampling efficiency Simple random sampling Spatially balanced sampling Systematic sampling Variance
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Touristic Ecological Footprint of Jiufeng National Forest Park in Beijing Based on Component Method
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作者 ZHANG Ying PAN Jing CHEN Ke 《Journal of Landscape Research》 2017年第5期47-52,共6页
This paper,based on the ecological footprint component method,calculated the touristic ecological footprint of Jiufeng National Forest Park in Beijing.The results showed that in 2013,in Jiufeng National Forest Park,th... This paper,based on the ecological footprint component method,calculated the touristic ecological footprint of Jiufeng National Forest Park in Beijing.The results showed that in 2013,in Jiufeng National Forest Park,the total touristic ecological footprint was 183.08 hm2,the total ecological capacity was 225.16 hm2,the total touristic ecological surplus was 42.07 hm2,and the average touristic ecological surplus was 0.000 4 hm2 per capita,indicating that tourism in Jiufeng National Forest Park was in ecological surplus and ecological security.However,forest parks in Beijing at large were in ecological deficit.This paper suggested that the tourist flow volume of forest parks with a big ecological deficit should be moved to forest parks with an ecological surplus.Besides,forest parks are expected to strengthen the development and management,improve the availability of forest recreation resource,and promote the environmental protection awareness of tourists,so as to boost the sustainable development of forest park tourism. 展开更多
关键词 forest tourism Ecological footprint Ecological capacity Ecological deficit national forest park BEIJING
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Evaluation of Four Seasons Soundscape in Meiling National Forest Park
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作者 CHEN Feiping WANG Yuqing +1 位作者 ZHAO Yi LI Hua 《Journal of Landscape Research》 2021年第4期73-76,79,共5页
To analyze the changes of soundscape elements in different seasons and periods,and to accurately grasp the internal operation law of soundscape,a questionnaire survey was conducted on the visitors of Meiling National ... To analyze the changes of soundscape elements in different seasons and periods,and to accurately grasp the internal operation law of soundscape,a questionnaire survey was conducted on the visitors of Meiling National Forest Park in four seasons.The average value method and factor analysis method were used to get people’s evaluation of forest soundscape and its influence on human psychology.The evaluation vocabulary of the four seasons psychological scale was summed up into the same 3 common factors,but the variables of each common factor were different,and the characteristics of the first factor were obvious,which was of great significance to the psychological expectation of the soundscape of Meiling National Forest Park.The soundscape of four seasons in Meiling National Forest Park has a natural and comfortable effect on human psychology on the whole.The soundscape impact factors in Meiling National Forest Park are very different in the primary and the secondary,and the expectations of forest soundscape tourists also vary greatly. 展开更多
关键词 forest SOUNDSCAPE Meiling national forest Park
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Using machine learning algorithms to estimate stand volume growth of Larix and Quercus forests based on national-scale Forest Inventory data in China 被引量:1
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作者 Huiling Tian Jianhua Zhu +8 位作者 Xiao He Xinyun Chen Zunji Jian Chenyu Li Qiangxin Ou Qi Li Guosheng Huang Changfu Liu Wenfa Xiao 《Forest Ecosystems》 SCIE CSCD 2022年第3期396-406,共11页
Estimating the volume growth of forest ecosystems accurately is important for understanding carbon sequestration and achieving carbon neutrality goals.However,the key environmental factors affecting volume growth diff... Estimating the volume growth of forest ecosystems accurately is important for understanding carbon sequestration and achieving carbon neutrality goals.However,the key environmental factors affecting volume growth differ across various scales and plant functional types.This study was,therefore,conducted to estimate the volume growth of Larix and Quercus forests based on national-scale forestry inventory data in China and its influencing factors using random forest algorithms.The results showed that the model performances of volume growth in natural forests(R^(2)=0.65 for Larix and 0.66 for Quercus,respectively)were better than those in planted forests(R^(2)=0.44 for Larix and 0.40 for Quercus,respectively).In both natural and planted forests,the stand age showed a strong relative importance for volume growth(8.6%–66.2%),while the edaphic and climatic variables had a limited relative importance(<6.0%).The relationship between stand age and volume growth was unimodal in natural forests and linear increase in planted Quercus forests.And the specific locations(i.e.,altitude and aspect)of sampling plots exhibited high relative importance for volume growth in planted forests(4.1%–18.2%).Altitude positively affected volume growth in planted Larix forests but controlled volume growth negatively in planted Quercus forests.Similarly,the effects of other environmental factors on volume growth also differed in both stand origins(planted versus natural)and plant functional types(Larix versus Quercus).These results highlighted that the stand age was the most important predictor for volume growth and there were diverse effects of environmental factors on volume growth among stand origins and plant functional types.Our findings will provide a good framework for site-specific recommendations regarding the management practices necessary to maintain the volume growth in China's forest ecosystems. 展开更多
关键词 Stand volume growth Stand origin Plant functional type national forest inventory data Random forest algorithms
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Developing allometric equations to estimate forest biomass for tree species categories based on phylogenetic relationships
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作者 Mingxia Yang Xiaolu Zhou +7 位作者 Changhui Peng Tong Li Kexin Chen Zelin Liu Peng Li Cicheng Zhang Jiayi Tang Ziying Zou 《Forest Ecosystems》 SCIE CSCD 2023年第4期494-503,共10页
The development of allometric biomass models is important process in biomass estimation because the reliability of forest biomass and carbon estimations largely depends on the accuracy and precision of such models.Nat... The development of allometric biomass models is important process in biomass estimation because the reliability of forest biomass and carbon estimations largely depends on the accuracy and precision of such models.National Forest Inventories(NFI)are detailed assessments of forest resources at national and regional levels that provide valuable data for forest biomass estimation.However,the lack of biomass allometric equations for each tree species in the NFI currently hampers the estimation of national-scale forest biomass.The main objective of this study was to develop allometric biomass regression equations for each tree species in the NFI of China based on limited biomass observations.These equations optimally grouped NFI and biomass observation species according to their phylogenetic relationships.Significant phylogenetic signals demonstrated phylogenetic conservation of the crown-to-stem biomass ratio.Based on phylogenetic relationships,we grouped and matched NFI and biomass observation species into 22 categories.Allometric biomass regression models were developed for each of these 22 species categories,and the models performed successfully(R^(2)=0.97,root mean square error(RMSE)=12.9​t·ha^(–1),relative RMSE=11.5%).Furthermore,we found that phylogeny-based models performed more effectively than wood density-based models.The results suggest that grouping species based on their phylogenetic relationships is a reliable approach for the development and selection of accurate allometric equations. 展开更多
关键词 Allometric equation forest biomass national forest Inventory Species grouping Tree architecture Wood density
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Machine learning and geostatistical approaches for estimating aboveground biomass in Chinese subtropical forests 被引量:4
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作者 Huiyi Su Wenjuan Shen +2 位作者 Jingrui Wang Arshad Ali Mingshi Li 《Forest Ecosystems》 SCIE CSCD 2020年第4期851-870,共20页
Background:Aboveground biomass(AGB)is a fundamental indicator of forest ecosystem productivity and health and hence plays an essential role in evaluating forest carbon reserves and supporting the development of target... Background:Aboveground biomass(AGB)is a fundamental indicator of forest ecosystem productivity and health and hence plays an essential role in evaluating forest carbon reserves and supporting the development of targeted forest management plans.Methods:Here,we proposed a random forest/co-kriging framework that integrates the strengths of machine learning and geostatistical approaches to improve the mapping accuracies of AGB in northern Guangdong Province of China.We used Landsat time-series observations,Advanced Land Observing Satellite(ALOS)Phased Array L-band Synthetic Aperture Radar(PALSAR)data,and National Forest Inventory(NFI)plot measurements,to generate the forest AGB maps at three time points(1992,2002 and 2010)showing the spatio-temporal dynamics of AGB in the subtropical forests in Guangdong,China.Results:The proposed model was capable of mapping forest AGB using spectral,textural,topographical variables and the radar backscatter coefficients in an effective and reliable manner.The root mean square error of the plotlevel AGB validation was between 15.62 and 53.78 t∙ha^(−1),the mean absolute error ranged from 6.54 to 32.32 t∙ha^(−1),the bias ranged from−2.14 to 1.07 t∙ha^(−1),and the relative improvement over the random forest algorithm was between 3.8%and 17.7%.The largest coefficient of determination(0.81)and the smallest mean absolute error(6.54 t∙ha^(−1)were observed in the 1992 AGB map.The spectral saturation effect was minimized by adding the PALSAR data to the modeling variable set in 2010.By adding elevation as a covariable,the co-kriging outperformed the ordinary kriging method for the prediction of the AGB residuals,because co-kriging resulted in better interpolation results in the valleys and plains of the study area.Conclusions:Validation of the three AGB maps with an independent dataset indicated that the random forest/cokriging performed best for AGB prediction,followed by random forest coupled with ordinary kriging(random forest/ordinary kriging),and the random forest model.The proposed random forest/co-kriging framework provides an accurate and reliable method for AGB mapping in subtropical forest regions with complex topography.The resulting AGB maps are suitable for the targeted development of forest management actions to promote carbon sequestration and sustainable forest management in the context of climate change. 展开更多
关键词 forest aboveground biomass Random forest co-kriging ALOS PALSAR Landsat TM national forest inventory Digital elevation model
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Mushroom Production as an Alternative for Rural Development in a Forested Mountainous Area 被引量:1
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作者 José A.BONET José R.GONZáLEZ-OLABARRIA Juan MARTíNEZ DE ARAGóN 《Journal of Mountain Science》 SCIE CSCD 2014年第2期535-543,共9页
Wild mushrooms are recognized as important non-wood forest products in mountainous ecosystems, but their real potential for generating rural economies has not been fully evaluated due to the difficulties in obtaining ... Wild mushrooms are recognized as important non-wood forest products in mountainous ecosystems, but their real potential for generating rural economies has not been fully evaluated due to the difficulties in obtaining reliable productivity data, minimizing their true potential as contributor to rural economies. Mushroom yield models based on large data series from Pinus forest ecosystems in the region of Catalonia(Spain), combined with data from the Spanish National Forest Inventory allow us to estimate the potential mushroom productivity by forest ecosystems. The results of 24,500 tons/yr of mushrooms of which 16,300 tons are classified as edible and 7,900 tons are commonly marketed demonstrate the importance of mushroom productions in Catalonian pine forests, mostly located in mountainous areas where the development of agricultural activities is limited. Economic mushroom value is estimated at 48 million € for the edible mushroom and 32 million € for those corresponding to marketable yields, confirming the potential of this non-wood forest product. These production results and corresponding economic values provide a basis for the incorporation of wild mushrooms as significant non-wood forest products in the development of forest policies in mountainous areas. 展开更多
关键词 Non-wood forest products Mushroom models national forest Inventory Economic value Mushroom potential estimation
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Dynamics of dead wood decay in Swiss forests 被引量:1
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作者 Oleksandra Hararuk Werner A.Kurz Markus Didion 《Forest Ecosystems》 SCIE CSCD 2020年第3期462-477,共16页
Background: Forests are an important component of the global carbon(C) cycle and can be net sources or sinks of CO2, thus mitigating or exacerbating the effects of anthropogenic greenhouse gas emissions. While forest ... Background: Forests are an important component of the global carbon(C) cycle and can be net sources or sinks of CO2, thus mitigating or exacerbating the effects of anthropogenic greenhouse gas emissions. While forest productivity is often inferred from national-scale yield tables or from satellite products, forest C emissions resulting from dead organic matter decay are usually simulated, therefore it is important to ensure the accuracy and reliability of a model used to simulate organic matter decay at an appropriate scale. National Forest Inventories(NFIs) provide a record of carbon pools in ecosystem components, and these measurements are essential for evaluating rates and controls of C dynamics in forest ecosystems. In this study we combine the observations from the Swiss NFIs and machine learning techniques to quantify the decay rates of the standing snags and downed logs and identify the main controls of dead wood decay.Results: We found that wood decay rate was affected by tree species, temperature, and precipitation. Dead wood originating from Fagus sylvatica decayed the fastest, with the residence times ranging from 27 to 54 years at the warmest and coldest Swiss sites, respectively. Hardwoods at wetter sites tended to decompose faster compared to hardwoods at drier sites, with residence times 45–92 and 62–95 years for the wetter and drier sites, respectively.Dead wood originating from softwood species had the longest residence times ranging from 58 to 191 years at wetter sites and from 78 to 286 years at drier sites.Conclusions: This study illustrates how long-term dead wood observations collected and remeasured during several NFI campaigns can be used to estimate dead wood decay parameters, as well as gain understanding about controls of dead wood dynamics. The wood decay parameters quantified in this study can be used in carbon budget models to simulate the decay dynamics of dead wood, however more measurements(e.g. of soil C dynamics at the same plots) are needed to estimate what fraction of dead wood is converted to CO2, and what fraction is incorporated into soil. 展开更多
关键词 Carbon residence time Carbon dynamics national forest Inventory
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上海城市山林——佘山国家森林公园 被引量:3
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作者 王爱民 李新国 《中国城市林业》 2008年第2期55-57,共3页
文章介绍了上海佘山国家森林公园的自然人文条件,重点阐述其植物景观资源,最后介绍了辰山植物园建设。1佘山国家森林公园地理人文条件及建园历史上海佘山国家森林公园——位于上海西郊松江区境内,占地401hm2,距市中心35km,是上海唯一的... 文章介绍了上海佘山国家森林公园的自然人文条件,重点阐述其植物景观资源,最后介绍了辰山植物园建设。1佘山国家森林公园地理人文条件及建园历史上海佘山国家森林公园——位于上海西郊松江区境内,占地401hm2,距市中心35km,是上海唯一的自然山林。分为东、西佘山园。 展开更多
关键词 Plant landscape Chenshan Botanical Garden Shanghai Sheshan national forest Park
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Mapping aboveground biomass and its prediction uncertainty using LiDAR and field data, accounting for tree-level allometric and LiDAR model errors 被引量:4
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作者 Svetlana Saarela AndréWästlund +5 位作者 Emma Holmström Alex Appiah Mensah Sören Holm Mats Nilsson Jonas Fridman Göran Ståhl 《Forest Ecosystems》 SCIE CSCD 2020年第3期562-578,共17页
Background: The increasing availability of remotely sensed data has recently challenged the traditional way of performing forest inventories, and induced an interest in model-based inference. Like traditional design-b... Background: The increasing availability of remotely sensed data has recently challenged the traditional way of performing forest inventories, and induced an interest in model-based inference. Like traditional design-based inference, model-based inference allows for regional estimates of totals and means, but in addition for wall-to-wall mapping of forest characteristics. Recently Light Detection and Ranging(LiDAR)-based maps of forest attributes have been developed in many countries and been well received by users due to their accurate spatial representation of forest resources. However, the correspondence between such mapping and model-based inference is seldom appreciated. In this study we applied hierarchical model-based inference to produce aboveground biomass maps as well as maps of the corresponding prediction uncertainties with the same spatial resolution. Further, an estimator of mean biomass at regional level, and its uncertainty, was developed to demonstrate how mapping and regional level assessment can be combined within the framework of model-based inference.Results: Through a new version of hierarchical model-based estimation, allowing models to be nonlinear, we accounted for uncertainties in both the individual tree-level biomass models and the models linking plot level biomass predictions with LiDAR metrics. In a 5005 km2 large study area in south-central Sweden the predicted aboveground biomass at the level of 18 m×18 m map units was found to range between 9 and 447 Mg·ha^-1. The corresponding root mean square errors ranged between 10 and 162 Mg·ha^-1. For the entire study region, the mean aboveground biomass was 55 Mg·ha^-1 and the corresponding relative root mean square error 8%. At this level 75%of the mean square error was due to the uncertainty associated with tree-level models.Conclusions: Through the proposed method it is possible to link mapping and estimation within the framework of model-based inference. Uncertainties in both tree-level biomass models and models linking plot level biomass with LiDAR data are accounted for, both for the uncertainty maps and the overall estimates. The development of hierarchical model-based inference to handle nonlinear models was an important prerequisite for the study. 展开更多
关键词 Aboveground biomass assessment forest mapping Gauss-Newton Regression Hierarchical Model-Based inference LiDAR maps national forest Inventory Uncertainty estimation Uncertainty map
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Stand-level biomass models for predicting C stock for the main Spanish pine species 被引量:4
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作者 Ana Aguirre Miren del Río +1 位作者 Ricardo Ruiz-Peinado Sonia Condés 《Forest Ecosystems》 SCIE CSCD 2021年第2期387-402,共16页
Background:National and international institutions periodically demand information on forest indicators that are used for global reporting.Among other aspects,the carbon accumulated in the biomass of forest species mu... Background:National and international institutions periodically demand information on forest indicators that are used for global reporting.Among other aspects,the carbon accumulated in the biomass of forest species must be reported.For this purpose,one of the main sources of data is the National Forest Inventory(NFI),which together with statistical empirical approaches and updating procedures can even allow annual estimates of the requested indicators.Methods:Stand level biomass models,relating the dry weight of the biomass with the stand volume were developed for the five main pine species in the Iberian Peninsula(Pinus sylvestris,Pinus pinea,Pinus halepensis,Pinus nigra and Pinus pinaster).The dependence of the model on aridity and/or mean tree size was explored,as well as the importance of including the stand form factor to correct model bias.Furthermore,the capability of the models to estimate forest carbon stocks,updated for a given year,was also analysed.Results:The strong relationship between stand dry weight biomass and stand volume was modulated by the mean tree size,although the effect varied among the five pine species.Site humidity,measured using the Martonne aridity index,increased the biomass for a given volume in the cases of Pinus sylvestris,Pinus halepensis and Pinus nigra.Models that consider both mean tree size and stand form factor were more accurate and less biased than those that do not.The models developed allow carbon stocks in the main Iberian Peninsula pine forests to be estimated at stand level with biases of less than 0.2 Mg·ha^(-1).Conclusions:The results of this study reveal the importance of considering variables related with environmental conditions and stand structure when developing stand dry weight biomass models.The described methodology together with the models developed provide a precise tool that can be used for quantifying biomass and carbon stored in the Spanish pine forests in specific years when no field data are available. 展开更多
关键词 Martonne aridity index Dry weight biomass Carbon stock national forest Inventory Peninsular pine forest Biomass expansion factor
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Mapping the potential distribution suitability of 16 tree species under climate change in northeastern China using Maxent modelling 被引量:2
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作者 Dan Liu Xiangdong Lei +7 位作者 Wenqiang Gao Hong Guo Yangsheng Xie Liyong Fu Yuancai Lei Yutang Li Zhuoli Zhang Shouzheng Tang 《Journal of Forestry Research》 SCIE CAS CSCD 2022年第6期1739-1750,共12页
Knowledge on the potential suitability of tree species to the site is very important for forest management planning.Natural forest distribution provides a good reference for afforestation and forest restoration.In thi... Knowledge on the potential suitability of tree species to the site is very important for forest management planning.Natural forest distribution provides a good reference for afforestation and forest restoration.In this study,we developed species distribution model(SDM)for 16 major tree species with 2,825 permanent sample plots with natural origin from Chinese National Forest Inventory data collected in Jilin Province using the Maxent model.Three types of environmental factors including bioclimate,soil and topography with a total of 33 variables were tested as the input.The values of area under the curve(AUC,one of the receiver operating characteristics of the Maxent model)in the training and test datasets were between 0.784 and 0.968,indicating that the prediction results were quite reliable.The environmental factors affecting the distribution of species were ranked in terms of their importance to the species distribution.Generally,the climatic factors had the greatest contribution,which included mean diurnal range,annual mean temperature,temperature annual range,and iosthermality.But the main environmental factors varied with tree species.Distribution suitability maps under current(1950-2000)and future climate scenarios(CCSM4-RCP 2.6 and RCP 6.0 during 2050)were produced for 16 major tree species in Jilin Province using the model developed.The predicted current and future ranges of habitat suitability of the 16 tree species are likely to be positively and negatively affected by future climate.Seven tree species were found to benefit from future climate including B etula costata,Fraxinus mandshurica,Juglans mandshurica,Phellodendron amurense,Populus ussuriensis,Quercus mongolica and Ulmus pumila;five tree species will experience decline in their suitable habitat including B.platyphylla,Tilia mongolica,Picea asperata,Pinus sylvestris,Pinus koraiensis;and four(Salix koreensis,Abies fabri,Pinus densiflora and Larix olgensis)showed the inconsistency under RCP 2.6 and RCP 6.0 scenarios.The maps of the habitat suitability can be used as a basis for afforestation and forest restoration in northeastern China.The SDMs could be a potential tool for forest management planning. 展开更多
关键词 Species distribution model national forest inventory data Natural forest Climate change Site suitability mapping Maxent modelling
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Longitudinal height-diameter curves for Norway spruce, Scots pine and silver birch in Norway based on shape constraint additive regression models 被引量:1
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作者 Matthias Schmidt Johannes Breidenbach Rasmus Astrup 《Forest Ecosystems》 SCIE CSCD 2018年第2期109-125,共17页
Background: Generalized height-diameter curves based on a re-parameterized version of the Korf function for Norway spruce (Piceo abies (L.) Karst.), Scots pine (Pinus sylvestris L.) and silver birch (Betula pe... Background: Generalized height-diameter curves based on a re-parameterized version of the Korf function for Norway spruce (Piceo abies (L.) Karst.), Scots pine (Pinus sylvestris L.) and silver birch (Betula pendula Roth) in Norwa are presented. The Norwegian National Forest Inventory (NFI) is used as data base for estimating the model parameters. The derived models are developed to enable spatially explicit and site sensitive tree height imputatio in forest inventories as well as future tree height predictions in growth and yield scenario simulations. Methods: Generalized additive mixed models (gamm) are employed to detect and quantify potentially non-linear effects of predictor variables. In doing so the quadratic mean diameter serves as longitudinal covariate since stand ag as measured in the NFI, shows only a weak correlation with a stands developmental status in Norwegian forests. Additionally the models can be locally calibrated by predicting random effects if measured height-diameter pairs are available. Based on the model selection of non-constraint models, shape constraint additive models (scare) were fit tc incorporate expert knowledge and intrinsic relationships by enforcing certain effect patterns like monotonicity. Results: Model comparisons demonstrate that the shape constraints lead to only marginal differences in statistical characteristics but ensure reasonable model predictions. Under constant constraints the developed models predict increasing tree heights with decreasing altitude, increasing soil depth and increasing competition pressure of a tree. / two-dimensional spatially structured effect of UTM-coordinates accounts for the potential effects of large scale spatial correlated covariates, which were not at our disposal. The main result of modelling the spatially structured effect is lower tree height prediction for coastal sites and with increasing latitude. The quadratic mean diameter affects both the level and the slope of the height-diameter curve and both effects are positive. Conclusions: In this investigation it is assumed that model effects in additive modelling of height-diameter curves which are unfeasible and too wiggly from an expert point of view are a result of quantitatively or qualitatively limited data bases. However, this problem can be regarded not to be specific to our investigation but more general since growth and yield data that are balanced over the whole data range with respect to all combinations of predictor variables are exceptional cases. Hence, scare may provide methodological improvements in several applications by combining the flexibility of additive models with expert knowledge. 展开更多
关键词 Height-diameter curve Norway spruce Scots pine Silver birch Norwegian national forest inventory Shape constrained additive models
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Model-based estimation of above-ground biomass in the miombo ecoregion of Zambia 被引量:1
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作者 James Halperin Valerie LeMay +2 位作者 Emmanuel Chidumayo Louis Verchot Peter Marshall 《Forest Ecosystems》 SCIE CSCD 2016年第4期258-274,共17页
Background:Information on above-ground biomass(AGB) is important for managing forest resource use at local levels,land management planning at regional levels,and carbon emissions reporting at national and internati... Background:Information on above-ground biomass(AGB) is important for managing forest resource use at local levels,land management planning at regional levels,and carbon emissions reporting at national and international levels.In many tropical developing countries,this information may be unreliable or at a scale too coarse for use at local levels.There is a vital need to provide estimates of AGB with quantifiable uncertainty that can facilitate land use management and policy development improvements.Model-based methods provide an efficient framework to estimate AGB.Methods:Using National Forest Inventory(NFI) data for a^1,000,000 ha study area in the miombo ecoregion,Zambia,we estimated AGB using predicted canopy cover,environmental data,disturbance data,and Landsat 8 OLI satellite imagery.We assessed different combinations of these datasets using three models,a semiparametric generalized additive model(GAM) and two nonlinear models(sigmoidal and exponential),employing a genetic algorithm for variable selection that minimized root mean square prediction error(RMSPE),calculated through cross-validation.We compared model fit statistics to a null model as a baseline estimation method.Using bootstrap resampling methods,we calculated 95% confidence intervals for each model and compared results to a simple estimate of mean AGB from the NFI ground plot data.Results:Canopy cover,soil moisture,and vegetation indices were consistently selected as predictor variables.The sigmoidal model and the GAM performed similarly;for both models the RMSPE was -36.8 tonnes per hectare(i.e.,57% of the mean).However,the sigmoidal model was approximately 30% more efficient than the GAM,assessed using bootstrapped variance estimates relative to a null model.After selecting the sigmoidal model,we estimated total AGB for the study area at 64,526,209 tonnes(+/- 477,730),with a confidence interval 20 times more precise than a simple designbased estimate.Conclusions:Our findings demonstrate that NFI data may be combined with freely available satellite imagery and soils data to estimate total AGB with quantifiable uncertainty,while also providing spatially explicit AGB maps useful for management,planning,and reporting purposes. 展开更多
关键词 national forest Inventory Above-ground biomass Miombo REDD+ Generalized additive model Nonlinear model Landsat 8 OLI
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Species-specific,pan-European diameter increment models based on data of 2.3 million trees
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作者 Mart-Jan Schelhaas Geerten M Hengeveld +11 位作者 Nanny Heidema Esther Thurig Brigitte Rohner Giorgio Vacchiano Jordi Vayreda John Redmond Jaroslaw Socha Jonas Fridman Stein Tomter Heino Polley Susana Barreiro Gert-Jan Nabuurs 《Forest Ecosystems》 SCIE CSCD 2018年第3期277-295,共19页
Background: Over the last decades, many forest simulators have been developed for the forests of individual European countries. The underlying growth models are usually based on national datasets of varying size, obta... Background: Over the last decades, many forest simulators have been developed for the forests of individual European countries. The underlying growth models are usually based on national datasets of varying size, obtained from National Forest Inventories or from long-term research plots. Many of these models include country-and location-specific predictors, such as site quality indices that may aggregate climate, soil properties and topography effects. Consequently, it is not sensible to compare such models among countries, and it is often impossible to apply models outside the region or country they were developed for. However, there is a clear need for more generically applicable but still locally accurate and climate sensitive simulators at the European scale, which requires the development of models that are applicable across the European continent. The purpose of this study is to develop tree diameter increment models that are applicable at the European scale, but still locally accurate. We compiled and used a dataset of diameter increment observations of over 2.3 million trees from 10 National Forest Inventories in Europe and a set of 99 potential explanatory variables covering forest structure, weather, climate, soil and nutrient deposition.Results: Diameter increment models are presented for 20 species/species groups. Selection of explanatory variables was done using a combination of forward and backward selection methods. The explained variance ranged from10% to 53% depending on the species. Variables related to forest structure(basal area of the stand and relative size of the tree) contributed most to the explained variance, but environmental variables were important to account for spatial patterns. The type of environmental variables included differed greatly among species.Conclusions: The presented diameter increment models are the first of their kind that are applicable at the European scale. This is an important step towards the development of a new generation of forest development simulators that can be applied at the European scale, but that are sensitive to variations in growing conditions and applicable to a wider range of management systems than before. This allows European scale but detailed analyses concerning topics like CO2 sequestration, wood mobilisation, long term impact of management, etc. 展开更多
关键词 European forests Diameter increment model Climate change Growth modelling national forest inventory
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Mapping forest vegetation patterns in an Atlantic-Mediterranean transitional area by integration of ordination and geostatistical techniques
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作者 Adriana E.Olthoff Cristina Gómez +1 位作者 Josu G.Alday Carolina Martínez-Ruiz 《Journal of Plant Ecology》 SCIE CSCD 2018年第1期114-122,共9页
Aims Forest vegetation variability may be explained by the complex inter-play among several spatial structuring factors,including climate and topography.We modelled the spatial variability of forest vegetation assembl... Aims Forest vegetation variability may be explained by the complex inter-play among several spatial structuring factors,including climate and topography.We modelled the spatial variability of forest vegetation assemblages and significant environmental variables along a com-plex environmental gradient or coenocline to produce a detailed cartographic database portraying the distribution of forests along it.Methods We combined an analysis of ordination coenoclines with kriging over 772 field data plots from the third Spanish National Forest Inventory in an Atlantic-Mediterranean transitional area(northern Spain).Important Findings The best fitted empirical semivariogram revealed a strong spatial structure of forest species composition along the complex envi-ronmental gradient considered(the climatic-topographic gradient from north to south).The steady and gradual increase of semivari-ance with a marked lag distance indicates a gradual turnover of forest assemblages according to the climatic-topographic vari-ations(regional or local).Two changes in the slope of the semi-variogram suggest the existence of two different scales of spatial variation.The interpolation map by Kriging of forest vegetation assemblages along the main coenocline shows a clear spatial dis-tribution pattern of trees and shrubs in accordance with the spa-tial variation of significant environmental variables.We concluded that the multivariate geostatistical approach is a suitable technique for spatial analysis of forest systems employing data from national forest inventories based on a regular network of field plots.The development of an assortment of maps describing changes in veg-etation assemblages and variation in environmental variables is expected to be a suitable tool for an integrated forest management and planning. 展开更多
关键词 coenocline KRIGING national forest Inventory ORDINATION VARIOGRAM
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