Timber cruising, forest inventory, and other related data collection methods that help managing forest operations and logging activities are necessary but expensive, mainly because conventional ground methods are labor intensive. On the other hand, projected labor shortages in the forestry sector is driving the industry to reduce its reliance on operators and field staff. It is why the exploration and demonstration of new sensor technologies and methodologies such as laser light detection and ranging (LiDAR) are attracting more and more attention.
LiDAR to the rescue
Advanced sensor and modelling technologies can facilitate forest inventory and compliance monitoring. One of these technologies, namely LiDAR, has been leading the way towards facilitating traditional ground survey.
The capabilities of new mobile LiDAR technology have been particularly noteworthy when it comes to precision inventory. FPInnovations pursued testing mobile LiDAR devices in the forest environment with respect to their portability, their high precision data points, as well as the development of automatic detection algorithms.
Promising test results
The FPInnovations trials showed that mobile LiDAR could be an accurate tool for extraction single tree level attributes such as stem location and diameter at the breast height (DBH). Recent tests indicate that mobile LiDAR could in fact be an efficient tool for enhanced forest inventory and stand structure characterization.
In certain cases, the research indicated that individual tree DBH estimates from mobile LiDAR data acquired over plots or transects can reach a 2-centimiter accuracy level. This makes the DBH estimates well within operational requirements.
The average accuracy of LiDAR-based estimation depends on several factors such as species composition, sensor moving trajectory, understory complexity, and laser scanning effective distance. To address these variables, FPInnovations is interested in open collaborations and in developing best practices of data acquisition and better modeling algorithms. This could minimize the impact of the variable factors in more complexed forest conditions, therefore achieve consistent estimations. The accurate sampling of trees and their DBHs obtained through mobile LiDAR technologies allows us to calculate basal area (BA) per hectare, which is another important stand attribute. The preliminary research outcomes have been summarized in FPInnovations’ technical reports over the past few years:
- Preliminary testing of mobile terrestrial LiDAR unit and future application considerations
- Stem and stand characterization using mobile terrestrial LiDAR in plantation and complex multi-cohort stands
- Towards real-time estimation of tree location, DBH, and terrain surface feature extraction from mobile LiDAR data
For more information, contact Jili Li, Remote Sensing Scientist, at email@example.com.