Forest Value Assessment with New LiDAR Technology

In June 13, 2017

Last week I attended the Elmia Wood Forestry Fair near Jönköping Sweden. I was there to meet with our Australasia Tablet EX Gear distributor but while I was there I took time to learn about technological advances that will assist forest managers. There was so much to learn that it was overwhelming!

One of the new pieces of technological kit that I learned more about is the BLK360 – Leica Geosystems new compact LiDAR scanner. I first heard of this scanner from Enda Keane of Treemetrics when it was made available by Leica in March this year. As Enda was also at the fair with some of the other Treemetrics team I took the opportunity to discuss how this scanner could be utilized by their clients to measure timber and in turn provide data that could be used to provide improved information regarding the timber quantity and quality.

I have been fortunate to have worked with Treemetrics on a couple of ground based LiDAR scanning projects a few years ago in Western Canada. They were great learning experiences which helped me appreciate the potential offered by ground based LiDAR scans when processed to produce models of the forest. However, what I didn’t like was having to lug around the Faro Scanner that we used to capture the data. The scanner is pretty bulky and weighs in at a little more than four kilograms – you can see the scanner in the photo above. In addition, a sturdy tripod is required to mount it on when scanning. This gets pretty heavy by the end of a field day! The new BLK360 weighs one kilogram and is only 100 mm in diameter and 165 mm high. For field staff this is a huge improvement in portability.

It is terrific that the scanner is so small and light. However, it is the improved capabilities that really will make ground based LiDAR scanning a hit with forest managers. What I believe to be the most important features are as follows:

  • Up to 40 scans can be captured on one battery. This should be more than enough for a full day in the field. With the Faro scanner two of us could manage only about a dozen scans per day but we were also only performing one scan per sample point. I would expect multiple scans would be performed with the BLK360 at each sample point (more on this below).
  • The scan density is more than enough to build accurate three-dimensional models of the sample trees. At ten meters from the scanner point densities can be set to achieve a “hit” every 6 mm with an accuracy of +/- 4mm. Lower density scans can also be selected.
  • The scanner will capture colour imagery with a 5-megapixel camera as well as thermal imagery. The imagery can be overlaid on the scan data to produce a 360° image. This can be useful for the identification of tree species, defects and canopy density by those viewing the data in an office. Other attributes could also be determined long after the scan is completed. This would allow changes in log quality standards to be incorporated into the processing of data without having to return to the field.
  • At a little less than $16,000 US this scanner is a bargain!
  • The scans can be viewed in near real time on an iPad using the ReCap Pro Application. This allows users to verify that the scans have captured all of the required data before leaving the site.
  • The ReCap Pro Application allows the user to make measurements on the scan. In addition, annotations and comments can be made on the scan. This creates an opportunity to change the way attributes are recorded that cannot be detected in the processed scan data.
  • Multiple scans are automatically stitched together to create a complete 3-D model of the area of interest.

It is the last three items above that I believe will take terrestrial LiDAR to the next level. Field staff will now be able to capture a scan of an area and then examine the scan data on an iPad to determine the best location for additional scans to capture data for 100% of the area of interest. In addition, trees could be tagged in the scan with information such as species and the location of defects that cannot be reliably identified in the processed scan data. This could be immensely valuable when capturing data for the calibration of airborne LiDAR. It would also allow for significantly higher sampling intensities at a lower total cost. This would yield much more reliable estimates of harvest volumes and values.

Of course this high density data only has value if it can be processed to produce something to guide forest management decisions. I will have more on this in another article.

By Brian Saunders, founder of Tablet-Ex-Gear Global