Forest genetics tree plots are large, multi-acre sites containing a viariety of carefully-bred trees growing in natural conditions to study their growth and mortality rates over the course of decades. Successful strains of trees are then used for reforestation efforts as a key part of Alberta's forestry industry.
These tree plots may contain thousands of trees on a grid, every individual of which is considered highly valuable to the long-term study and industry. However, the sheer number of trees poses a logistical and financial challenge to monitoring their growth; foresters have to measure tree heights using laborous ground-based processes that takes crews of multiple people a minute or more per tree to conduct. As a result, current practice is to only take a small (<10%) subsample of the entire tree population for assessment and study, and the methods may be prone to sources of error such as observer bias and wide equipment tolerances.
Since we have used UAV photogrammetry to survey hectare-scale tree plots with high precision and accuracy (see our development project), we propose that the same methods can be applied to forest genetics tree plots to conduct exhaustive, every-last-tree surveys of tree heights with greater precision and lower field costs than current field methods.
In 2017, we teamed up with Blue Ridge Lumber, a subsidiary of West Fraser Timber, to conduct UAV surveys across all their lodgepole pine forest genetics tree plots in the Swan Hills, while crews on the ground conducted their normal tree height measurement routines on select trees.
Our ultimate objectives are: to validate the method and demonstrate the precision, accuracy and feasibility of UAV surveys for this application, and to provide tree height data for the entire tree populations of four forest genetics plots (tens of thousands of trees) to Blue Ridge Lumber.
We would like to extend our appreciation to Blue Ridge Lumber, who are graciously supporting this project by covering our crew and logistics costs.