An all-electrical dendrometer based on a frequency-shift sensor

• A new dendrometer measures stem diameter with high accuracy and reliability by employing a frequency-shift detection mechanism. • The sensor demonstrates operation across a significantly wider dynamic range compared to other available solutions, with significantly reduced maintenance requirements. • Measurement readout is sufficiently stable under varying environmental conditions to provide reliable trunk diameter variations (TDV) measurements, required for water status estimate. • The standardized interface, small size, and reduced component count of the design enable easy integration into agricultural systems. Effective agricultural irrigation scheduling requires precise monitoring of plant water stress. This can be achieved by measuring the temporospatial variations in trunk diameter using dendrometers; however, commercially available devices are limited by their restricted dynamic range, high manufacturing cost, and operational challenges. This study introduces an all-electrical, band-type dendrometer based on a frequency-shift sensor. The design offers temporospatial resolutions that meet industry standards while maintaining a lightweight, cost-effective, and compact form. The dendrometer's performance was validated through laboratory testing and outdoor comparisons with commercial devices, demonstrating similar sensitivity and readout stability across relevant field conditions. Its low cost and straightforward interface with data loggers make it well-suited for large sensor networks, and its sensing principle supports further system miniaturization.