Development of Low-cost automatic point dendrometers

PI: Cyrille Rathgeber (UMR 1092 LERFOB)

______________________________________

Context — Tree stem radius variations can be monitored accurately for a long period of time using automatic point dendrometers providing information on secondary growth dynamics. However these devices pose two main problems: (1) they are very expensive preventing their use in most field studies, and (2) the large amount of perfectly timed data they produce is difficult to interpret from a biological point of view, e.g. it is very difficult to extract a clean growth signal.

Objectives — In this project, we aim to overcome these two major problems in order to make automatic point dendrometers a basic tool for forest monitoring studies.

Approaches — To tackle the cost problem, we will develop further our own low-cost dendrometers made using common linear detectors. We aim to divide the total production cost by 10 using these sensors compared to the market dendrometers which are using more sophisticated and expensive LVDT sensors. To tackle the problem of biological interpretation of the results, dendrometer data will be compared to direct measurements of xylem development using two innovative and complementary approaches: (1) a statistical approaches involving generalized additive models (GAM), and (2) a process-based modelling approaches involving a model of water and sugar transport in the tree.

Expected results and impacts — This project can lead to important technical and scientific outcomes. From a technical point of view, we aim at developing effective “low-cost” automatic point dendrometers accompanied with a detailed technical documentation and a companion paper on how to use them.