Assessment of Stem Volume on Plots Using Terrestrial Laser Scanner: A Precision Forestry Application

Area of Science:

• Forestry Science
• Remote Sensing
• Geomatics

Background:

• Accurate timber volume estimation is crucial for ecological assessment and economic revenue.
• Traditional forest inventory methods can be labor-intensive and time-consuming.
• Advancements in remote sensing offer potential for more efficient and precise forest measurements.

Purpose of the Study:

• To assess the accuracy of terrestrial laser scanning (TLS) for estimating total tree height and diameter at breast height (DBH).
• To compare two distinct methods for total tree height estimation: treetop detection (H_TTD) and stem cross-section centers (H_TSP).
• To evaluate the accuracy of these measurements for semi-automatic stem volumetric modeling.

Main Methods:

• Utilized a Trimble TX8 survey-grade terrestrial laser scanner (TLS) to generate detailed 3D point clouds.
• Applied a modified local maxima algorithm for treetop detection (H_TTD) and stem cross-section analysis for height estimation (H_TSP).
• Employed an algebraic circle-fitting algorithm with hierarchical cluster analysis (HCA) for DBH estimation.

Main Results:

• Both H_TTD and H_TSP methods demonstrated strong correlations with measured total stem volumes (R² = 0.87–0.98).
• Estimated stem volumes showed minimal differences compared to reference measurements, particularly for Norway spruce.
• The study confirmed the feasibility of using TLS data for accurate, semi-automatic stem volume modeling.

Conclusions:

• TLS provides a highly accurate method for deriving key tree metrics like height and DBH.
• The tested height estimation methods (H_TTD and H_TSP) are reliable for volumetric modeling.
• Finer-resolution remote sensing data, like TLS, represents a significant advancement for precision forestry, especially in small-scale applications.