What is a dendrometer? - Facts about dendrometers
Two different measuring devices were installed for the project to measure the growth of the tree circumference.
- Digital dendrometers (very short measuring intervals, high precision)
- Analog dendrometers (cheaper, higher quantity)
Digital dendrometers consist of a linear digital potentiometer in a housing, which is attached to the trunk with a steel band. When the trunk expands or contracts, the tape transmits this to the potentiometer by deflecting it (Deslauriers et al. 2007). The measurement can be stored in a fixed time interval by the digital dendrometer. The change in stem diameter can be recorded with a resolution of 0.001 mm (https://www.emsbrno.cz/p.axd/en/Dendrometer.DRL26D.html).
Analog dendrometers consist of a spring-loaded "vernier" scale engraved on steel, which is also attached to the tree with a steel band. As the tree grows or shrinks, the spring gives way, the scale reflects the deflection, and the corresponding value can be read on the scale (Palmer & Ogden 2012).
Both types of dendrometers are designed in such a way that the dendrometer tape does not cut off the tree as it grows. They therefore do not harm the tree! On the contrary, the dendrometers provide important information about the health and growth of our urban trees, which helps to protect more trees.
To ensure that the measurements of the change in trunk diameter are as accurate as possible, it is important that the dendrometers are not touched or moved. This is because they are very precise and even the smallest disturbances can distort the measurements.
Unfortunately, measuring devices such as the dendrometers are repeatedly removed or damaged, which is a major problem for the project.
