Magnetic Dendrometer

Plants Vibrate, but cannot be seen with the naked eye

I know, it sounds “far out” but bear with me. Plants expand and contract in diameter, following 24-hr Diurnal fluctuations (day/night cycles). These micrometer-scale vibrations stem from the liminal connection plants span between Earth, Atmosphere, and Space through the media of water and solar radiation. Through the process of Transpiration water transitions via root systems into the atmosphere. Meanwhile, photons from the sun are captured and converted into material energy.

Plant scientists can monitor these minuscule expansions and contractions to gain deep insights into irrigation needs, water and heat stress, and disease. Dendrometers are one plant-based tool that have shown potential to improve irrigation management in high-value woody perennial crops. High-precision dendrometers continuously measure small fluctuations (± 10 microns) in stem diameter throughout the day, which directly correlates to water stress. However, currently available dendrometers are expensive, have mechanical hysteresis, and are subject to issues such as material expansion; weather and animal disruptions; and bulky, invasive design. The Dendrometer created at the OPEnS Lab alleviates these key failure points using zero-thermal expansion carbon fiber, spring tension, and a linear magnetic encoder. Mass deployment of these automated dendrometers has the potential to provide a continuous picture of vineyard water stress at the whole-block level, thus providing valuable decision support for vineyard irrigation management.