Piecewise segmentation approaches of plant volume estimation methods are presented. The primary 3-D reference shape of a target plant is obtained through the 3-D point cloud generation using multi-view stereo techniques. Then, the entire shape region is segmented into multiple pieces to calculate the plant volume. Two different segmentation method of i) slice-based and ii) cell-based are adopted. In the slice-based model, the entire point cloud is horizontally split into slices, whereas in the cell-based model, it is divided into small cubical cells. After that, volume estimation procedures for the two models are applied. Various experiments were performed to test validity of presented methods. Experiments to find the proper number of segments for the methods were also performed.