{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,1,19]],"date-time":"2026-01-19T10:53:02Z","timestamp":1768819982548,"version":"3.49.0"},"reference-count":61,"publisher":"MDPI AG","issue":"1","license":[{"start":{"date-parts":[[2019,12,24]],"date-time":"2019-12-24T00:00:00Z","timestamp":1577145600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>Accurately measuring tree diameter at breast height (DBH) and estimating tree positions in a sample plot are important in tree mensuration. The main aims of this paper include (1) developing a new, integrated device that can identify trees using the quick response (QR) code technique to record tree identifications, measure DBH, and estimate tree positions concurrently; (2) designing an innovative algorithm to measure DBH using only two angle sensors, which is simple and can reduce the impact of eccentric stems on DBH measures; and (3) designing an algorithm to estimate the position of the tree by combining ultra-wide band (UWB) technology and altitude sensors, which is based on the received signal strength indication (RSSI) algorithm and quadrilateral localization algorithm. This novel device was applied to measure ten 10 \u00d7 10 m square plots of diversified environments and various tree species to test its accuracy. Before measuring a plot, a coded sticker was fixed at a height of 1.3 m on each individual tree stem, and four UWB module anchors were set up at the four corners of the plot. All individual trees\u2019 DBHs and positions within the plot were then measured. Tree DBH, measured using a tree caliper, and the values of tree positions, measured using tape, angle ruler, and inclinometer, were used as the respective reference values for comparison. Across the plots, the decode rate of QR codes was 100%, with an average response time less than two seconds. The DBH values had a bias of 1.89 mm (1.88% in relative terms) and a root mean square error (RMSE) of 5.38 mm (4.53% in relative terms). The tree positions were accurately estimated; the biases on the x-axis and the y-axis of the tree position were \u22128.55\u201314.88 cm and \u221212.07\u201324.49 cm, respectively, and the corresponding RMSEs were 12.94\u201333.96 cm and 17.78\u201328.43 cm. The average error between the estimated and reference distances was 30.06 cm, with a standard deviation of 13.53 cm. The device is cheap and friendly to use in addition to its high accuracy. Although further studies are needed, our method provides a great alternative to conventional tools for improving the efficiency and accuracy of tree mensuration.<\/jats:p>","DOI":"10.3390\/s20010144","type":"journal-article","created":{"date-parts":[[2019,12,24]],"date-time":"2019-12-24T10:28:43Z","timestamp":1577183323000},"page":"144","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":11,"title":["An Integrated Method for Coding Trees, Measuring Tree Diameter, and Estimating Tree Positions"],"prefix":"10.3390","volume":"20","author":[{"given":"Linhao","family":"Sun","sequence":"first","affiliation":[{"name":"Key Laboratory of Forestry Intelligent Monitoring and Information Technology Research of Zhejiang Province, Zhejiang A &amp; F University, Lin\u2019an 311300, Zhejiang, China"},{"name":"School of Information Engineering, Zhejiang A &amp; F University, Lin\u2019an 311300, Zhejiang, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Luming","family":"Fang","sequence":"additional","affiliation":[{"name":"Key Laboratory of Forestry Intelligent Monitoring and Information Technology Research of Zhejiang Province, Zhejiang A &amp; F University, Lin\u2019an 311300, Zhejiang, China"},{"name":"School of Information Engineering, Zhejiang A &amp; F University, Lin\u2019an 311300, Zhejiang, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2554-1028","authenticated-orcid":false,"given":"Yuhui","family":"Weng","sequence":"additional","affiliation":[{"name":"Arthur Temple College of Forestry and Agriculture, Stephen F. Austin State University, Nacogdoches, TX 75962, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Siqing","family":"Zheng","sequence":"additional","affiliation":[{"name":"Key Laboratory of Forestry Intelligent Monitoring and Information Technology Research of Zhejiang Province, Zhejiang A &amp; F University, Lin\u2019an 311300, Zhejiang, China"},{"name":"School of Information Engineering, Zhejiang A &amp; F University, Lin\u2019an 311300, Zhejiang, China"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2019,12,24]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","unstructured":"Mikita, T., Janata, P., and Surov\u1ef3, P. (2016). Forest stand inventory based on combined aerial and terrestrial close-range photogrammetry. Forests, 7.","DOI":"10.3390\/f7080165"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"814","DOI":"10.1126\/science.aac6759","article-title":"Forest health and global change","volume":"349","author":"Trumbore","year":"2015","journal-title":"Science"},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"3","DOI":"10.1016\/j.foreco.2015.02.006","article-title":"Global forest resources assessment 2015: What, why and how?","volume":"352","author":"MacDicken","year":"2015","journal-title":"For. Ecol. Manag."},{"key":"ref_4","doi-asserted-by":"crossref","unstructured":"Fan, Y., Feng, Z., Mannan, A., Ullah Khan, T., Shen, C., and Saeed, S. (2018). Estimating tree position, diameter at breast height, and tree height in real-time using a mobile phone with RGB-D SLAM. Remote Sens., 10.","DOI":"10.3390\/rs10111845"},{"key":"ref_5","first-page":"286","article-title":"Light detection and ranging (LIDAR): An emerging tool for multiple resource inventory","volume":"103","author":"Reutebuch","year":"2005","journal-title":"J. For."},{"key":"ref_6","doi-asserted-by":"crossref","unstructured":"Jenkins, C., Chojnacky, D., Heath, L., and Birdsey, R. (2004). Comprehensive Database of Diameter-Based Biomass Regressions for North American Tree Species.","DOI":"10.2737\/NE-GTR-319"},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"460","DOI":"10.1111\/2041-210X.12670","article-title":"Terrestrial photogrammetry: A non-destructive method for modelling irregularly shaped tropical tree trunks","volume":"8","author":"Bauwens","year":"2017","journal-title":"Methods Ecol. Evol."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"63","DOI":"10.1016\/j.isprsjprs.2016.01.006","article-title":"Terrestrial laser scanning in forest inventories","volume":"115","author":"Liang","year":"2016","journal-title":"ISPRS J. Photogramm. Remote Sens."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"38","DOI":"10.3390\/f8020038","article-title":"Assessing precision in conventional field measurements of individual tree attributes","volume":"8","author":"Ville","year":"2017","journal-title":"Forests"},{"key":"ref_10","first-page":"570","article-title":"A review of past research on dendrometers","volume":"46","author":"Clark","year":"2000","journal-title":"For. Sci."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"715","DOI":"10.1139\/x81-099","article-title":"Stem eccentricity in coastal western Hemlock","volume":"11","author":"Kellogg","year":"1981","journal-title":"Can. J. For. Res."},{"key":"ref_12","unstructured":"Mat\u00e9rn, B. (1990). On the shape of the cross-section of a tree stem. An Empirical Study of the Geometry of Mensurational Methods, Sveriges lantbruksuniversitet."},{"key":"ref_13","first-page":"365","article-title":"Out-of-roundness in douglas-fir stems","volume":"21","author":"Williamson","year":"1975","journal-title":"For. Sci."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"487","DOI":"10.1007\/s00468-013-0965-y","article-title":"Spiral grain in bristlecone pines (Pinus longaeva) exhibits no correlation with environmental factors","volume":"28","author":"Wing","year":"2014","journal-title":"Trees Struct. Funct."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"856","DOI":"10.3389\/fpls.2015.00856","article-title":"Capturing spiral radial growth of conifers using the superellipse to model tree-ring geometric shape","volume":"6","author":"Shi","year":"2015","journal-title":"Front. Plant Sci."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"599","DOI":"10.1093\/aob\/mcu175","article-title":"Functional-structural plant models: A growing paradigm for plant studies","volume":"114","author":"Godin","year":"2014","journal-title":"Ann. Bot."},{"key":"ref_17","first-page":"164","article-title":"Automatic dendrometry: Tree detection, tree height and diameter estimation using terrestrial laser scanning","volume":"69","author":"Cabo","year":"2018","journal-title":"Int. J. Appl. Earth Obs. Geoinf."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"357","DOI":"10.14358\/PERS.72.4.357","article-title":"Detection of individual tree crowns in airborne Lidar data","volume":"72","author":"Koch","year":"2006","journal-title":"Photogram. Eng. Remote Sens."},{"key":"ref_19","unstructured":"Alavalapati, J.R.R., and Carter, D.R. (2004). A comparison of four forest inventory tools in southeast Arkansas. Competitiveness of Southern Forest Products Markets in a Global Economy: Trends and Predictions, Proceedings of the Southern Forest Economics Workshop, St. Augustine, FL, USA, 14\u201316 March 2004, University of Florida. Available online: http:\/\/www.sofew.cfr.msstate.edu\/papers\/0304tallant.pdf."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"197","DOI":"10.5558\/tfc71197-2","article-title":"Comparison of relative accuracy and time requirement between the caliper, the diameter tape and an electronic tree measuring fork","volume":"71","author":"Binot","year":"1995","journal-title":"For. Chron."},{"key":"ref_21","doi-asserted-by":"crossref","unstructured":"Kangas, A., and Maltamo, M. (2006). Forest Inventory: Methodology and Applications, Springer Science & Business Media.","DOI":"10.1007\/1-4020-4381-3"},{"key":"ref_22","first-page":"82","article-title":"Developing portable system for measuring diameter at breast height","volume":"40","author":"Sun","year":"2018","journal-title":"J. B For. Univ."},{"key":"ref_23","first-page":"1","article-title":"Automatic measurement of DBH with electronic bar","volume":"48","author":"Jingchen","year":"2017","journal-title":"Trans. Chin. Soc. Agric. Mach."},{"key":"ref_24","first-page":"189","article-title":"Design and experiment of portable high precision equipment for tree diameter measurement","volume":"49","author":"Haiyang","year":"2018","journal-title":"Trans. Chin. Soc. Agric. Mach."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"1614","DOI":"10.3390\/s130201614","article-title":"Automatic stem mapping by merging several terrestrial laser scans at the feature and decision levels","volume":"13","author":"Liang","year":"2013","journal-title":"Sensors"},{"key":"ref_26","unstructured":"Avery, T.E., and Burkhart, H.E. (2002). Forest Measurements, McGraw-Hill Cop."},{"key":"ref_27","doi-asserted-by":"crossref","unstructured":"Martin, M., Jozef, V., Juli\u00e1n, T., Grzn\u00e1rov\u00e1, A., Valent, P., Slav\u00edk, M., and Mergani\u010d, J. (2018). High precision individual tree diameter and perimeter estimation from Close-Range photogrammetry. Forests, 9.","DOI":"10.3390\/f9110696"},{"key":"ref_28","doi-asserted-by":"crossref","unstructured":"Mokro\u0161, M., Liang, X., Surov\u00fd, P., Valent, P., \u010cer\u0148ava, J., Chud\u00fd, F., Tun\u00e1k, D., Salo\u0148, \u0160., and Mergani\u010d, J. (2018). Evaluation of Close-Range Photogrammetry Image Collection Methods for Estimating Tree Diameters. ISPRS Int. J. Geo-Inf., 7.","DOI":"10.3390\/ijgi7030093"},{"key":"ref_29","unstructured":"Olofsson, K., Lindberg, E., and Holmgren, J. (2008, January 17\u201319). A method for linking field-surveyed and aerial-detected single trees using cross correlation of position images and the optimization of weighted tree list graphs. Proceedings of the SilviLaser, Edinburgh, UK."},{"key":"ref_30","unstructured":"Lindberg, E., Holmgren, J., Olofsson, K., and Olsson, H. (2010, January 14\u201317). Estimation of stem attributes using a combination of terrestrial and airborne laser scanning. Proceedings of the SilviLaser, Freiburg, Germany."},{"key":"ref_31","doi-asserted-by":"crossref","unstructured":"Vauhkonen, J., Maltamo, M., and McRoberts, R.E. (2014). Applications of Airborne Laser Scanning, Springer. Chapter 4.3.3.","DOI":"10.1007\/978-94-017-8663-8"},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"661","DOI":"10.1109\/TGRS.2011.2161613","article-title":"Automatic stem mapping using single-scan terrestrial laser scanning","volume":"50","author":"Liang","year":"2012","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"1252","DOI":"10.1016\/j.agrformet.2011.05.004","article-title":"Estimating leaf area distribution in savanna trees from terrestrial LiDAR measurements","volume":"151","author":"Widlowski","year":"2011","journal-title":"Agric. For. Meteorol."},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"1877","DOI":"10.3390\/rs70201877","article-title":"Terrestrial laser scanning as an effective tool to retrieve tree level height, crown width, and stem diameter","volume":"7","author":"Srinivasan","year":"2015","journal-title":"Remote Sens."},{"key":"ref_35","doi-asserted-by":"crossref","unstructured":"Hyypp\u00e4, J., Virtanen, J.-P., Jaakkola, A., Yu, X., Hyypp\u00e4, H., and Liang, X. (2017). Feasibility of Google Tango and Kinect for crowdsourcing forestry information. Forests, 9.","DOI":"10.3390\/f9010006"},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"109","DOI":"10.1016\/j.compag.2017.07.015","article-title":"Tango in forests\u2013An initial experience of the use of the new Google technology in connection with forest inventory tasks","volume":"141","year":"2017","journal-title":"Comput. Electron. Agric."},{"key":"ref_37","doi-asserted-by":"crossref","unstructured":"Surov\u00fd, P., Yoshimoto, A., and Panagiotidis, D. (2016). Accuracy of reconstruction of the tree stem surface using terrestrial close-range photogrammetry. Remote Sens., 8.","DOI":"10.3390\/rs8020123"},{"key":"ref_38","doi-asserted-by":"crossref","unstructured":"Forsman, M., B\u00f6rlin, N., and Holmgren, J. (2016). Estimation of tree stem attributes using terrestrial photogrammetry with a camera rig. Forests, 7.","DOI":"10.3390\/f7030061"},{"key":"ref_39","unstructured":"(2019, August 16). QR Code Tutorial. Available online: https:\/\/www.thonky.com\/qr-code-tutorial\/introduction."},{"key":"ref_40","unstructured":"(2019, August 16). Gainscha, NiceLabel 2017 Barcode Software. Available online: http:\/\/cn.gainscha.com\/gjxz.html."},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"1740035","DOI":"10.1142\/S0217984917400358","article-title":"A QR code identification technology in package auto-sorting system","volume":"31","author":"Di","year":"2017","journal-title":"Mod. Phys. Lett. B"},{"key":"ref_42","doi-asserted-by":"crossref","first-page":"1417","DOI":"10.1016\/j.chb.2012.03.004","article-title":"The psychology behind QR codes: User experience perspective","volume":"28","author":"Jaemin","year":"2012","journal-title":"Comput. Hum. Behav."},{"key":"ref_43","first-page":"22","article-title":"QR Codes 101","volume":"39","author":"Crompton","year":"2012","journal-title":"Learn. Lead. Technol."},{"key":"ref_44","doi-asserted-by":"crossref","unstructured":"Sun, S., Hu, J., Li, J., Liu, R., Shu, M., and Yang, Y. (2019). An INS-UWB based collision avoidance system for AGV. Algorithms, 12.","DOI":"10.3390\/a12020040"},{"key":"ref_45","doi-asserted-by":"crossref","first-page":"42","DOI":"10.1007\/978-3-642-37192-9_5","article-title":"Impact of the number of beacons in PSO-based auto-localization in UWB networks","volume":"Volume 7835","author":"Monica","year":"2013","journal-title":"Applications of Evolutionary Computation"},{"key":"ref_46","doi-asserted-by":"crossref","unstructured":"Krishnan, S., Sharma, P., Guoping, Z., and Woon, O.H. (2007, January 24\u201326). A uwb based localization system for indoor robot navigation. Proceedings of the IEEE International Conference on UltraWideband, Singapore.","DOI":"10.1109\/ICUWB.2007.4380919"},{"key":"ref_47","doi-asserted-by":"crossref","first-page":"111","DOI":"10.1007\/978-3-319-40159-1_9","article-title":"A comparison of accurate indoor localization of static targets via WiFi and UWB ranging","volume":"Volume 9662","author":"Monica","year":"2016","journal-title":"Trends in Practical Applications of Scalable Multi-Agent Systems"},{"key":"ref_48","doi-asserted-by":"crossref","unstructured":"Matteo, R., Samuel, V.D.V., Heidi, S., and De Poorter, E. (2018). Analysis of the scalability of UWB indoor localization Solutions for High User Densities. Sensors, 18.","DOI":"10.3390\/s18061875"},{"key":"ref_49","doi-asserted-by":"crossref","unstructured":"Xiaoping, H., Fei, W., Jian, Z., Hu, Z., and Jin, J. (2019). A posture recognition method based on indoor positioning technology. Sensors, 19.","DOI":"10.3390\/s19061464"},{"key":"ref_50","first-page":"58","article-title":"Model of human body influence on UWB ranging error","volume":"38","author":"He","year":"2017","journal-title":"J. Commun."},{"key":"ref_51","doi-asserted-by":"crossref","unstructured":"Juri, S., Volker, S., Norbert, S., Arensa, M., and Hugentobler, U. (2019). Decawave UWB clock drift correction and powerself-calibration. Sensors, 19.","DOI":"10.3390\/s19132942"},{"key":"ref_52","doi-asserted-by":"crossref","first-page":"37","DOI":"10.4236\/cn.2013.52B007","article-title":"RSSI-based algorithm for indoor localization","volume":"5","author":"Zhu","year":"2013","journal-title":"Commun. Netw."},{"key":"ref_53","doi-asserted-by":"crossref","unstructured":"Hamdoun, S., Rachedi, A., and Benslimane, A. (2013, January 19\u201321). Comparative analysis of RSSI-based indoor localization when using multiple antennas in Wireless Sensor Networks. Proceedings of the International Conference on Selected Topics in Mobile & Wireless Networking (MoWNeT), Montreal, QC, Canada.","DOI":"10.1109\/MoWNet.2013.6613811"},{"key":"ref_54","doi-asserted-by":"crossref","unstructured":"Altoaimy, L., Mahgoub, I., and Rathod, M. (2014, January 15\u201319). Weighted localization in Vehicular Ad Hoc Networks using vehicle-to-vehicle communication. Proceedings of the Global Information Infrastructure and Networking Symposium (GIIS), Montreal, QC, Canada.","DOI":"10.1109\/GIIS.2014.6934270"},{"key":"ref_55","doi-asserted-by":"crossref","unstructured":"Barral, V., Escudero, C.J., Garc\u00eda-Naya, J.A., and Maneiro-Catoira, R. (2019). NLOS identification and mitigation using low-cost UWB devices. Sensors, 19.","DOI":"10.3390\/s19163464"},{"key":"ref_56","doi-asserted-by":"crossref","first-page":"187","DOI":"10.1023\/A:1013767926256","article-title":"The Anatomy of a Context-Aware Application","volume":"8","author":"Harter","year":"2002","journal-title":"Wirel. Netw."},{"key":"ref_57","doi-asserted-by":"crossref","first-page":"334","DOI":"10.3390\/electronics8030334","article-title":"Hybrid indoor localization using WiFi and UWB technologies","volume":"8","author":"Stefania","year":"2019","journal-title":"Electronics"},{"key":"ref_58","first-page":"108","article-title":"Quadrilateral localization algorithm for wireless sensor networks","volume":"27","author":"Wen","year":"2008","journal-title":"Trans. Microsyst. Technol."},{"key":"ref_59","doi-asserted-by":"crossref","unstructured":"Gao, H., and Xu, L. (2019). Tightly-coupled vehicle positioning method at intersections aided by UWB. Sensors, 19.","DOI":"10.3390\/s19132867"},{"key":"ref_60","doi-asserted-by":"crossref","first-page":"1026","DOI":"10.1109\/JSAC.2010.100907","article-title":"NLOS identification and mitigation for localization based on UWB experimental data","volume":"28","author":"Marano","year":"2010","journal-title":"IEEE J. Sel. Areas Commun."},{"key":"ref_61","doi-asserted-by":"crossref","first-page":"301","DOI":"10.1007\/s12243-009-0124-z","article-title":"Survey of NLOS identification and error mitigation problems in UWB-based positioning algorithms for dense environments","volume":"65","author":"Khodjaev","year":"2010","journal-title":"Ann. Telecommun."}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/20\/1\/144\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T13:45:24Z","timestamp":1760190324000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/20\/1\/144"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2019,12,24]]},"references-count":61,"journal-issue":{"issue":"1","published-online":{"date-parts":[[2020,1]]}},"alternative-id":["s20010144"],"URL":"https:\/\/doi.org\/10.3390\/s20010144","relation":{},"ISSN":["1424-8220"],"issn-type":[{"value":"1424-8220","type":"electronic"}],"subject":[],"published":{"date-parts":[[2019,12,24]]}}}