Using fibre-optic sensing for non-invasive, continuous dendrometry of mature tree trunks

Dendrometry is the main non-invasive macroscopic technique commonly used in plant physiology and ecophysysiology studies. Over the years several types of dendrometric techniques have been developed, each with their respective strengths and drawbacks. Automatic and continuous monitoring solutions are being developed, but are still limited, particularly for non-invasive monitoring of large-diameter trunks. In this study, we propose a new type of automated dendrometer based on distributed fibre-optic sensing that continuously measures the change in stem circumference, is non-invasive, and has no upper limit on the trunk diameter on which it can be installed. We perform a three-month validation experiment during which we deploy a fibre-optic cable at three localities around the trunks of two specimens of Brachychiton. We verify the accuracy of this new method through comparison against a conventional point-dendrometer, and we observe a consistent time lag between the various measurement locations that varies with the meteorological conditions. Finally, we discuss the feasibility of the fibre-based dendrometer in the context of existing dendrometric techniques and practical experimental considerations.This repository contains the data and scripts to reproduce the results from this study. Please refer to README.md to get started.

树木测径术（Dendrometry）是植物生理学与生态生理学研究中常用的主流非侵入式宏观检测技术。多年来，学界已开发出多种测径技术，各类技术各有其独特优势与局限。当前自动连续监测方案虽已在研发中，但应用仍存在局限，尤其针对大直径树干的非侵入式监测场景。本研究提出一种基于分布式光纤传感（distributed fibre-optic sensing）的新型自动测径仪，可连续监测茎干周长变化，具备非侵入式特性，且对可安装的树干直径无上限限制。我们开展了为期三个月的验证实验，在两株瓶树（Brachychiton）的树干周围三个位置布设了光纤线缆。通过与传统点式测径仪（point-dendrometer）对比，验证了该新方法的测量精度；同时观测到不同测量位置间存在稳定的时间延迟，且该延迟随气象条件变化而改变。最后，我们结合现有测径技术体系与实际实验考量，探讨了基于光纤的测径仪的应用可行性。本仓库包含可复现本研究结果的实验数据与代码脚本，请参阅README.md文件以快速上手。