Relationship between tree row LIDAR-volume and leaf area density for fruit orchards and vineyards obtained with a LIDAR 3D Dynamic Measurement System

Abstract

In this work, a LIDAR 3D Dynamic Measurement System, based on a Two-Dimensional Terrestrial Laser-LIDAR Scanner (2D TLS), was used for the geometric characterisation of tree-row crops (apple trees, pear trees and vineyards). The trees were scanned with the LIDAR system from opposite sides to obtain two three-dimensional point clouds. The point clouds were registered and the volume occupied by the resulting point cloud, tree row LIDAR-volume (TRLV), was graphically and numerically obtained. The study undertaken in this paper is based on the hypothesis that there may exist a non-linear relationship between the TRLV and the leaf area density (LAD). The main objective is to examine the relationship between TRLV and LAD in vineyards, apple and pear orchards. The study of 35 blocks of vegetation reveals a good logarithmic fit, y=−0.36ln(x)+3.69 with R2=0.87, between the TRLV (x) in dm3 and the LAD (y) in dm−1. It would appear that the TRLV of the crops under study (planted in a hedgerow-type configuration) is in itself an explanation of the LAD. The competition for light between the leaves and the space that these leaves occupy appear to follow a similar model in the three crops. According to the results of this study, the LAD can be estimated from the TRLV. If the LAD is multiplied by the TRLV, the leaf area of the vegetation under study can be obtained. It is therefore concluded that by using the information provided by the LIDAR 3D Dynamic Measurement System, a good estimation can be obtained of the leaf area in hedgerow fruit tree crops and hedgerow vineyards.