Using your phone as a digital inventory tool

Diameter at the breast height (DBH) is essential in single tree and stand measurement, spanning a wide range of applications, from traditional forestry to carbon accounting, ecology, forest inventories and forest monitoring. Although they can provide instant readings, traditional DBH measurement methods still rely heavily on mechanical measurement, and often lack the capability of storing, transferring and, therefore, making a better use of the collected data.

In addition, they may take a longer measurement cycle time and may provide poorer ergonomic and safety conditions, mainly because they imply a direct contact measurement, and make use of rather heavy to carry tools; operating costs could be another good reason when checking for their economic performance, since they typically require more human resources as compared to digital tools.

These characteristics make them rather incompatible with the modern concepts of sustainable forestry, at least under economic and ergonomics points of view. In addition, they cannot provide the data in the required format and information flows as specific to Forestry 4.0 and individual tree detection and measurement.

The latest developments in proximal sensing technology, as well as the integration of advanced sensors in smart portable devices have provided new opportunities for measuring tree biometrics at affordable costs and with minimal inputs of resources. Technologies such as those developed by Google for Android-based platforms, or by Apple for iPhone and iPad platforms have already been tested in measuring the main biometrics of trees and logs with promising results. These were complemented by studies that tested or described the capabilities of professional LiDAR scanners and which concluded that such devices may reach a high accuracy when used in forestry applications, including for the measurement of main biometrics of the trees or logs.

Still, the main challenges of using professional LiDAR scanners are those related to the investments in equipment, which remained high over the last years, as well as in a lower portability, which make them less suitable when working in rough terrain. In some data collection configurations, one may add the occlusion effects, which may lead to loosing important data. Obviously, the use of low-weight and highly mobile devices such as the smartphones may overcome many of these limitations but, irrespective of the device used, instant readings of the measurement results, as well as the capability to store, document and transfer the data are important features to consider when choosing a measurement solution.

These requirements constrain the available set of digital DBH measurement solutions to couple of software applications such as developed by Arboreal Forest and Measure App developed by Apple . Both of them take advantage of close-range LiDAR sensing and Augmented Reality technology, which comes handy for orientation and effective operation, and provide instant readings of the measurement results as opposed to the use of rather resource intensive algorithms to obtain the results in an offline approach.

The Arboreal Forest app features several advanced features such as those related to species recognition, DBH and height measurement, and setting of inventory plots, in addition to a dedicated platform for data transfer and storage.

A recent study was setup to compare the readings on DBH as they were taken by the Arboreal Forest and Measure App to the readings taken manually by a digital caliper. The main aim of the study was to describe and characterize the accuracy of the two tested digital methods in relation to the manual method.

The study concluded that digital DBH measurement options supported by affordable mobile platforms equipped with LiDAR and AR technologies are accurate and compatible with the DBH measurement requirements when compared to the manual option.

More >> and commentary on the study results from Arboreal Forest can be read here.

As part of this year’s ForestTECH 2024 series running in Rotorua, New Zealand on 20-21 November and in Melbourne, Australia on 26-27 November, Sweden’s Arboreal Forest’s CEO and Founder, Johan Ekenstedt will be outlining to local foresters, how an in-phone Lidar and scanner (the Arboreal Forest app from the App Store) can and are being used as an alternative to traditional manual tree measurement methods.

Source: Ecological Informatics, Arboreal Forest