Drones to monitor 3D woody crops and measuring the area, height and volume of trees

B. Drone being piloted by researcher Jorge Torres-Sánchez

ImaPing Research Group (www.ias.csic.es/en/imaping), led by Dr. Francisca López-Granados of the Institute for Sustainable Agriculture from Cordoba, a center of the Spanish National Research Council-CSIC, has developed an innovative method for measuring three-dimensional geometric data (area, height and volume) tree in woody crops from aerial images taken with a drone.

The method, recently published in the PLOS ONE journal (http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0130479), was tuned in the two systems most widespread woody crops, i.e. plantations scattered trees and plantations in hedge, and is applied in two consecutive phases: 1) generation of digital surface models based technology Unmanned Aerial Vehicles (UAV) or drones and 2) using image analysis techniques based on objects. “We worked in olive orhards as an example of a woody crop, due to their great impact on the Mediterranean Basin and other parts of the world where the olive groves are an emerging crop (for example: Chile, California-USA, and several regions of China). However, one of the advantages of our research is that this method could be extrapolated to forest plantations using corresponding adjustments “, indicates Francisca López-Granados.

“The results were excellent as the projected area of ​​each tree was measured with 97% accuracy and minimum deviations on height data and estimated volume were observed in the studied fields”, explains the researcher José Manuel Peña. With this technology, the user can map hundreds of trees very accurately and quickly, being more efficient than the laborious and inconsistent alternative measures taken only on-ground in the field. “In addition to providing detailed information on the size and development of each tree, the maps generated let study the geo-spatial relationships of trees with agronomic factors in their environment, such as soil properties, the presence of weeds, etc. Therefore, the joint analysis of this information allows designing optimal crop management strategies (pruning, weed control and pests, application of irrigation and nutrients, etc.) in the context of precision agriculture, generating significant economic, management and agro-environment benefits”, points out José Manuel Peña.

A. 3D Modelling of aerial images taken by a drone