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In precision agriculture, light detection and ranging (LiDAR) technologies are currently used to monitor crop growth, plant phenotyping, and biomass dynamics at the ecosystem scale. In this study, we utilized a UAV\u2013LiDAR sensor to monitor two crop fields and a set of machine learning (ML) methods to predict real-time AGB over two consecutive years in the region of Mid-Jutland, Denmark. During each crop growing period, UAV surveys were conducted in parallel with AGB destructive sampling every 7\u201315 days, the AGB samples from which were used as the ground truth data. We evaluated the ability of the ML models to estimate the real-time values of AGB at a sub-meter resolution (0.17\u20130.52 m2). An extremely randomized trees (ERT) regressor was selected for the regression analysis, based on its predictive performance for the first year\u2019s growing season. The model was retrained using previously identified hyperparameters to predict the AGB of the crops in the second year. The ERT performed AGB estimation using height and reflectance metrics from LiDAR-derived point cloud data and achieved a prediction performance of R2 = 0.48 at a spatial resolution of 0.35 m2. The prediction performance could be improved significantly by aggregating adjacent predictions (R2 = 0.71 and R2 = 0.93 at spatial resolutions of 1 m2 and 2 m2, respectively) as they ultimately converged to the reference biomass values because any individual errors averaged out. The AGB prediction results were examined as function of predictor type, training set size, sampling resolution, phenology, and canopy density. The results demonstrated that when combined with ML regression methods, the UAV\u2013LiDAR method could be used to provide accurate real-time AGB prediction for crop fields at a high resolution, thereby providing a way to map their biochemical constituents.<\/jats:p>","DOI":"10.3390\/rs14163912","type":"journal-article","created":{"date-parts":[[2022,8,15]],"date-time":"2022-08-15T23:44:03Z","timestamp":1660607043000},"page":"3912","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":32,"title":["Above-Ground Biomass Prediction for Croplands at a Sub-Meter Resolution Using UAV\u2013LiDAR and Machine Learning Methods"],"prefix":"10.3390","volume":"14","author":[{"given":"Jaime C.","family":"Revenga","sequence":"first","affiliation":[{"name":"Department of Geosciences and Natural Resources Management (IGN), Copenhagen University, DK-1350 Copenhagen, Denmark"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9040-4409","authenticated-orcid":false,"given":"Katerina","family":"Trepekli","sequence":"additional","affiliation":[{"name":"Department of Geosciences and Natural Resources Management (IGN), Copenhagen University, DK-1350 Copenhagen, Denmark"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-0240-1559","authenticated-orcid":false,"given":"Stefan","family":"Oehmcke","sequence":"additional","affiliation":[{"name":"Department of Geosciences and Natural Resources Management (IGN), Copenhagen University, DK-1350 Copenhagen, Denmark"},{"name":"Department of Computer Science (DiKU), Copenhagen University, DK-2100 Copenhagen, Denmark"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Rasmus","family":"Jensen","sequence":"additional","affiliation":[{"name":"Department of Geosciences and Natural Resources Management (IGN), Copenhagen University, DK-1350 Copenhagen, Denmark"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Lei","family":"Li","sequence":"additional","affiliation":[{"name":"Department of Computer Science (DiKU), Copenhagen University, DK-2100 Copenhagen, Denmark"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2868-0856","authenticated-orcid":false,"given":"Christian","family":"Igel","sequence":"additional","affiliation":[{"name":"Department of Computer Science (DiKU), Copenhagen University, DK-2100 Copenhagen, Denmark"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Fabian Cristian","family":"Gieseke","sequence":"additional","affiliation":[{"name":"Department of Computer Science (DiKU), Copenhagen University, DK-2100 Copenhagen, Denmark"},{"name":"Department of Information Systems, University of M\u00fcnster, 48149 M\u00fcnster, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-5633-6097","authenticated-orcid":false,"given":"Thomas","family":"Friborg","sequence":"additional","affiliation":[{"name":"Department of Geosciences and Natural Resources Management (IGN), Copenhagen University, DK-1350 Copenhagen, Denmark"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2022,8,12]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","unstructured":"Maimaitijiang, M., Sagan, V., Sidike, P., Daloye, A.M., Erkbol, H., and Fritschi, F.B. 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