Abstract
First post in a series on a laser-based pulling-test method. Peer-reviewed in Forests 2026, 17(5), 528 — Open Access.
The classical pulling test remains the only method that can estimate both anchorage and stem strength. Force, stem-base tilt, and strain yield safety factors against uprooting and breakage.
In practice, however, the usual sensors hit limits:
- Large, stiff trees need high test loads before inclinometers and elastometers deliver usable signals.
- Standing deadwood (habitat trees / snags) must be loaded only cautiously; at small loads the signal-to-noise ratio suffers — and extrapolation becomes uncertain.
- Acceleration-related artefacts distort tilt measurements, especially in wind and higher up the stem.
That is where the laser-based method comes in: emitters on the stem project spots onto a semi-transparent screen; a camera records the motion. From this follow tilt, bending, and lateral displacement — contactless, high-resolution, with clearly less scatter in the force–tilt relationship.
In short: we resolve the start of the load–response curve more cleanly. That is the prerequisite for more reliable extrapolation from smaller reactions — and for extending pulling tests to large trees and critical snags.
In the follow-up posts: setup, validation, bending vs. tipping, LiDAR, and limitations.
Further reading: Rust et al., Forests 2026, 17, 528. https://doi.org/10.3390/f17050528