  While mobile LiDAR sensors are increasingly used to scan in ecology and
forestry applications, reconstruction and characterisation are typically
carried out offline (to the best of our knowledge). Motivated by this, we
present an online LiDAR system which can run on a handheld device to segment
and track individual trees and identify them in a fixed coordinate system.
Segments relating to each tree are accumulated over time, and tree models are
completed as more scans are captured from different perspectives. Using this
reconstruction we then fit a cylinder model to each tree trunk by solving a
least-squares optimisation over the points to estimate the Diameter at Breast
Height (DBH) of the trees. Experimental results demonstrate that our system can
estimate DBH to within $\sim$7 cm accuracy for 90% of individual trees in a
forest (Wytham Woods, Oxford)
