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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

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Forest Ecosystems 2018年第2期5卷 109-125页

作者： Matthias Schmidt Johannes Breidenbach rasmus astrup Northwest German Forest Research Institute Forest Growth Gratzelstr 2 37079 Gottingen Germany Norwegian Institute for Bioeconomy Research National Forest Inventory Postboks 115 1431 As Norway

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

关键词： Height-diameter curve Norway spruce Scots pine Silver birch Norwegian national forest inventory Shape constrained additive models

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Estimating wood quality attributes from dense airborne LiDAR point clouds

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Forest Ecosystems 2024年第2期11卷 226-235页

作者： Nicolas Cattaneo Stefano Puliti Carolin Fischer rasmus astrup Norwegian Institute of Bioeconomy Research(NIBIO) Division of Forest and Forest ResourcesHøgskoleveien 81433ÅsNorway

Mapping individual tree quality parameters from high-density LiDAR point clouds is an important step towards improved forest *** present a novel machine learning-based workflow that uses individual tree point clouds from drone laser scanning to predict wood quality indicators in standing *** object reconstruction methods,our approach is based on simple metrics computed on vertical slices that summarize information on point distances,angles,and geometric attributes of the space between and around the *** models use these slice metrics as predictors and achieve high accuracy for predicting the diameter of the largest branch per log (DLBs) and stem diameter at different heights (DS) from survey-grade drone laser *** show that our models are also robust and accurate when tested on suboptimal versions of the data generated by reductions in the number of points or emulations of suboptimal single-tree segmentation *** approach provides a simple,clear,and scalable solution that can be adapted to different situations both for research and more operational mapping.

关键词： UAV laser scanning Wood quality Machine learning Point cloud metrics

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Mapping forest age using National Forest Inventory,airborne laser scanning,and Sentinel-2 data

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Forest Ecosystems 2020年第4期7卷 793-806页

作者： Johannes Schumacher Marius Hauglin rasmus astrup Johannes Breidenbach National Forest Inventory Norwegian Institute of Bioeconomy ResearchÅsNorway

Background:The age of forest stands is critical information for forest management and conservation,for example for growth modelling,timing of management activities and harvesting,or decisions about protection ***,area-wide information about forest stand age often does not *** this study,we developed regression models for large-scale area-wide prediction of age in Norwegian *** model development we used more than 4800 plots of the Norwegian National Forest Inventory(NFI)distributed over Norway between latitudes 58°and 65°N in an 18.2 Mha study *** variables were based on airborne laser scanning(ALS),Sentinel-2,and existing public map *** performed model validation on an independent data set consisting of 63 spruce stands with known ***:The best modelling strategy was to fit independent linear regression models to each observed site index(SI)level and using a SI prediction map in the application of the *** most important predictor variable was an upper percentile of the ALS heights,and root mean squared errors(RMSEs)ranged between 3 and 31 years(6%to 26%)for SI-specific models,and 21 years(25%)on *** deviance(MD)ranged between^(−1) and 3 *** models improved with increasing SI and the RMSEs were largest for low SI stands older than 100 *** a mapped SI,which is required for practical applications,RMSE and MD on plot level ranged from 19 to 56 years(29%to 53%),and 5 to 37 years(5%to 31%),*** the validation stands,the RMSE and MD were 12(22%)and 2 years(3%),***:Tree height estimated from airborne laser scanning and predicted site index were the most important variables in the models describing ***,we obtained good results,especially for stands with high *** models could be considered for practical applications,although we see considerable potential for improvements if better SI maps were available.

关键词： Forest age Lidar Optical satellite images Remote sensing Forest inventory

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A century of National Forest Inventory in Norway–informing past,present,and future decisions

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Forest Ecosystems 2020年第4期7卷 602-620页

作者： Johannes Breidenbach Aksel Granhus Gro Hylen Rune Eriksen rasmus astrup National Forest Inventory Norwegian Institute of Bioeconomy ResearchÅsNorway

Past:In the early twentieth century,forestry was one of the most important sectors in Norway and an agitateddiscussion about the perceived decline of forest resources due to over-exploitation was *** base thediscussion on facts,the young state of Norway established Landsskogtakseringen–the world’s first National ForestInventory(NFI).Field work started in 1919 and was carried out by *** were recorded on 10m wide stripswith 1–5 km *** quality and land cover categories were recorded along each *** for the firstcounty were published in 1920,and by 1930 most forests below the coniferous tree line were *** 2ndto 5th inventories followed in the years 1937–*** of 1954,temporary sample plot clusters on a 3 km×3 kmgrid were used as sampling ***:The current NFI grid was implemented in the 6th NFI from 1986 to 1993,when permanent plots ona 3 km×3 km grid were established below the coniferous tree *** of the 7th inventory in 1994,the NFIis continuous,and 1/5 of the plots are measured *** trees with a diameter≥5 cm are recorded oncircular,250 m2 *** NFI grid was expanded in 2005 to cover alpine regions with 3 km×9 km and 9km×9 km *** 2012,the NFI grid within forest reserves was doubled along the cardinal *** temporary plots are used periodically to facilitate county-level *** of today,more than 120variables are recorded in the NFI including bilberry cover,drainage status,deadwood,and forest *** are monitored and trees outside forests are ***:Considerable research efforts towards the integration of remote sensing technologies enable thepublication of the Norwegian Forest Resource Map since 2015,which is also used for small area estimation atthe municipality *** the analysis side,capacity and software for long term growth and yield prognosisare being ***,we foresee the inclusion of further variables for monitoring ec

关键词： Forest forest annually

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Large scale mapping of forest attributes using heterogeneous sets of airborne laser scanning and National Forest Inventory data

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Forest Ecosystems 2021年第4期8卷 872-886页

作者： Marius Hauglin Johannes Rahlf Johannes Schumacher rasmus astrup Johannes Breidenbach Norwegian Institute of Bioeconomy Research AsNorway

Background:The Norwegian forest resource map(SR16)maps forest attributes by combining national forest inventory(NFI),airborne laser scanning(ALS)and other remotely sensed *** the ALS data were acquired over a time interval of 10 years using various sensors and settings,the NFI data are continuously *** of this study were to analyze the effects of stratification on models linking remotely sensed and field data,and assess the accuracy overall and at the ALS project *** and methods:The model dataset consisted of 9203 NFI field plots and data from 367 ALS projects,covering 17 Mha and 2/3 of the productive forest in ***-effects regression models were used to account for differences among ALS *** types of stratification were used to fit models:1)stratification by the three main tree species groups spruce,pine and deciduous resulted in species-specific models that can utilize a satellite-based species map for improving predictions,and 2)stratification by species and maturity class resulted in stratum-specific models that can be used in forest management inventories where each stand regularly is visually stratified *** models were compared to general models that were fit without stratifying the ***:The species-specific models had relative root-mean-squared errors(RMSEs)of 35%,34%,31%,and 12% for volume,aboveground biomass,basal area,and Lorey’s height,*** RMSEs were 2-7 percentage points(pp)smaller than those of general *** validating using predicted species,RMSEs were 0-4 *** than those of general *** stratified by main species and maturity class further improved RMSEs compared to species-specific models by up to 1.8 *** mixed-effects models over ordinary least squares models resulted in a decrease of RMSE for timber volume of 1.0-3.9 pp.,depending on the main tree *** for timber volume ranged between 19%-59% among individual ALS ***

关键词： NFI Lidar Mixed-effects models Wall-to-wall mapping

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The effects of data aggregation on long-term projections of forest stands development

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Forest Ecosystems 2024年第3期11卷 381-389页

作者： Kobra Maleki rasmus astrup Nicolas Cattaneo Wilson Lara Henao Clara Anton-Fernandez Norwegian Institute of Bioeconomy Research Division of Forestry and Forest ResourcesP.O.Box 115ÅsNO-1431Norway

Forest management planning often relies on Airborne Laser Scanning(ALS)-based Forest Management Inventories(FMIs)for sustainable and efficient *** the area-based(ABA)approach,these inventories estimate forest characteristics for grid cell areas(pixels),which are then usually summarized at the stand *** the ALS-based high-resolution Norwegian Forest Resource Maps(16 m×16 m pixel resolution)alongside with stand-level growth and yield models,this study explores the impact of three levels of pixel aggregation(standlevel,stand-level with species strata,and pixel-level)on projected stand *** results indicate significant differences in the projected outputs based on the aggregation ***,the most substantial difference in estimated volume occurred between stand-level and pixel-level aggregation,ranging from-301 to+253 m^(3)·ha^(-1)for single *** differences were,on average,higher for broadleaves than for spruce and pine dominated stands,and for mixed stands and stands with higher variability than for pure and homogenous *** conclusion,this research underscores the critical role of input data resolution in forest planning and management,emphasizing the need for improved data collection practices to ensure sustainable forest management.

关键词： Growth and yield models Dominant species Norway spruce Scots pine Broadleaves Forest resource map Stand variability

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Full scale amendment of a contaminated wood impregnation site with iron water treatment residues

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Frontiers of Environmental Science & Engineering 2016年第4期10卷 169-178页

作者： Sanne Skov NIELSEN Peter KJELDSEN rasmus JAKOBSEN Orbicon Ringstedvej 20 DK-4000 Roskilde Denmark Department of Environmental Engineering Technical University of Denmark Miljovej 113 DK-2800 Kgs. Lyngby Denmark Geological Survey of Denmark and Greenland Geological Survey of Denmark and Greenland Oster Voldgade 10 DK-1350 Copenhagen K Denmark

Iron water treatment residues （Fe-WTR） are a free by-product of the treatment of drinking water with high concentration of iron oxides and potential for arsenic sorption. This paper aims at applying Fe- WTR to a contaminated site, measuring the reduction in contaminant leaching, and discussing the design of delivery and mixing strategy for soil stabilization at field scale and present a cost-effective method of soil mixing by connnon contractor machinery. Soil contaminated by As, Cr, and Cu at an abandoned wood impregnation site was amended with 0.22% （dw） Fe-WTR. To evaluate the full scale amendment a 100 mtest site and a control site （without amendment） were monitored for 14 months. Also soil analysis of Fe to evaluate the degree of soil and Fe-WTR mixing was done. Stabilization with Fe-WTR had a significant effect on leachable contaminants, reducing pore water As by 93%, Cu by 91% and Cr by 95% in the upper samplers. Dosage and mixing of Fe-WTR in the soil proved to be difficult in the deeper part of the field, and Pire water concentrations of arsenic was generally *** water logged conditions no increase in dissolved iron or arsenic was observed in the amended soil. Our field scale amendment of contaminated soil was overall successful in decreasing leaching of As, Cr and Cu. With minor improvements in the mixing and delivery strategy, this stabilization method is suggested for use in cases, where leaching ofCu, Cr and As constitutes a risk for groundwater and freshwater.

关键词： Field experiment Iron oxide Arsenic Stabilization Wood preservation sites

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CO_2 Capture technologies: Current status and new directions using supported ionic liquid phase (SILP) absorbers

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Science China Chemistry 2012年第8期55卷 1648-1656页

作者： KOLDING Helene FEHRMANN rasmus RIISAGER Anders Centre for Catalysis and Sustainable Chemistry Department of Chemistry Building 207 Technical University of Denmark2800 Kgs. Lyngby Denmark

Current state-of-the-art techniques for COz capture are presented and discussed, Post-combustion capture of CO2 by absorption is the technology most easily retrofitted to existing installations, but at present this is not economically viable to install and run. Using ionic liquids instead of aqueous amine solutions overcomes the major thermodynamic issues. By applying SILP tech- nology further advances, in terms of ease of handling and sorption dynamics, are obtained. Initial experimental studies showed that ionic liquids such as tetrahexylammonium prolinate, [N6666][Pro], provide a good candidate for CO2 absorption using SILP technology. Thus a solid SILP absorber comprised of 40 wt% [N6666][Pro] loaded on precalcined silica quantitatively takes up about 1.2 mole CO2 per mole of ionic liquid in consecutive absorption-desorption cycles in a flow-experiment per- formed with 0.09 bar of CO2 （9% CO2 in He）.

关键词： CO2 capture absorption ionic liquids SILP absorber

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Erroneous use of Statistics behind Claims of a Major Solar Role in Recent Warming

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Research in Astronomy and Astrophysics 2022年第12期22卷 224-231页

作者： Mark T.Richardson rasmus E.Benestad Jet Propulsion Laboratory California Institute of TechnologyPasadenaCA 91109USA Department of Atmospheric Science Colorado State UniversityFt CollinsCO 90732USA Norwegian Meteorological Institute NO-0313 OsloNorway

In a study that attempted to relate solar and human activity to Earth's recent temperature change,Connolly et *** a basic error in the choice of statistical methods and so overreported the effect of the Sun.A major theme of their study was that there are many data sets of past solar activity,and some of these allegedly provide statistical evidence of“most of the recent global warming being due to changes in solar activity.”We avoid methods that are known to give inaccurate results and show that for 1970–2005 Northern Hemisphere land the corrected solar attribution fraction is-7%to+5%,compared with values of up to 64%reported in Connolly et *** higher values are entirely due to mistaken application of ***,we cannot test truly“recent”global warming since most of their solar data sets end before 2015,and two finish in the 1990s,but all tested post-1970 periods show similarly small solar *** solar-climate linkage is an area of fascinating and ongoing research with rigorous technical *** argue that instead of repeating errors,they should be acknowledged and corrected so that the debate can focus on areas of legitimate scientific uncertainty.

关键词： Earth (Sun:)solar-terrestrial relations Physical Data and Processes

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Field scale interaction and nutrient exchange between surface water and shallow groundwater in the Baiyang Lake region,North China Plain

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Journal of Environmental Sciences 2016年第7期28卷 60-75页

作者： Bentje Brauns Poul L.Bjerg Xianfang Song rasmus Jakobsen Department of Environmental Engineering Technical University of Denmark State Key Laboratory of Water Cycle and Related Land Surface Processes Institute of Geographic Sciences and Natural Resources ResearchChinese Academy of Sciences Sino-Danish Center for Education and Research Geological Survey of Denmark and Greenland

Fertilizer input for agricultural food production, as well as the discharge of domestic and industrial water pollutants, increases pressures on locally scarce and vulnerable water resources in the North China Plain. In order to：（a） understand pollutant exchange between surface water and groundwater,（b） quantify nutrient loadings, and（c） identify major nutrient removal pathways by using qualitative and quantitative methods, including the geochemical model PHREEQC） a one-year study at a wheat（Triticum aestivum L.） and maize（Zea mays L.） double cropping system in the Baiyang Lake area in Hebei Province, China, was undertaken. The study showed a high influence of low-quality surface water on the shallow aquifer. Major inflowing pollutants into the aquifer were ammonium and nitrate via inflow from the adjacent Fu River（up to 29.8 mg/L NH4-N and 6.8 mg/L NO3-N）, as well as nitrate via vertical transport from the field surface（up to 134.8 mg/L NO3-N in soil water）. Results from a conceptual model show an excess nitrogen input of about 320 kg/ha/a. Nevertheless,both nitrogen species were only detected at low concentrations in shallow groundwater,averaging at 3.6 mg/L NH4-N and 1.8 mg/L NO3-N. Measurement results supported by PHREEQC-modeling indicated cation exchange, denitrification, and anaerobic ammonium oxidation coupled with partial denitrification as major nitrogen removal pathways. Despite the current removal capacity, the excessive nitrogen fertilization may pose a future threat to groundwater quality. Surface water quality improvements are therefore recommended in conjunction with simultaneous monitoring of nitrate in the aquifer, and reduced agricultural N-inputs should be considered.

关键词： Groundwater pollution North China Plain Surface water–groundwater interaction Wheat–maize double cropping Nitrogen Anammox

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