The main goal of the R package 'treeDbalance' is to provide functions for the computation of several measurements of 3D node imbalance and their respective 3D tree imbalance indices, as well as to introduce the new 'phylo3D' format for rooted 3D tree objects. Moreover, it encompasses an example dataset of 3D models of 63 beans in 'phylo3D' format. Please note that this R package was developed alongside the project described in the manuscript 'Measuring 3D tree imbalance of plant models using graph-theoretical approaches' by M. Fischer, S. Kersting, and L. Kühn (2023) <doi:10.48550/arXiv.2307.14537>, which provides precise mathematical definitions of the measurements. Furthermore, the package contains several helpful functions, for example, some auxiliary functions for computing the ancestors, descendants, and depths of the nodes, which ensures that the computations can be done in linear time. Most functions of 'treeDbalance' require as input a rooted tree in the 'phylo3D' format, an extended 'phylo' format (as introduced in the R package 'ape' 1.9 in November 2006). Such a 'phylo3D' object must have at least two new attributes next to those required by the 'phylo' format: 'node.coord', the coordinates of the nodes, as well as 'edge.weight', the literal weight or volume of the edges. Optional attributes are 'edge.diam', the diameter of the edges, and 'edge.length', the length of the edges. For visualization purposes one can also specify 'edge.type', which ranges from normal cylinder to bud to leaf, as well as 'edge.color' to change the color of the edge depiction. This project was supported by the joint research project DIG-IT! funded by the European Social Fund (ESF), reference: ESF/14-BM-A55-0017/19, and the Ministry of Education, Science and Culture of Mecklenburg-Western Pomerania, Germany, as well as by the the project ArtIGROW, which is a part of the WIR!-Alliance 'ArtIFARM – Artificial Intelligence in Farming' funded by the German Federal Ministry of Education and Research (FKZ: 03WIR4805).