Monitoring spatiotemporal soil moisture changes in the subsurface of forest sites using electrical resistivity tomography (ERT)

Abstract The effects of drought on tree mortality at forest stands are not completely understood. For assessing their water supply, knowledge the small-scale distribution soil moisture as well its temporal changes is a key issue in an era climate change. However, traditional methods like taking samples or installing data loggers solely collect parameters single point small volume. Electrical resistivity tomography (ERT) suitable method for monitoring and has rarely been used forests. This was applied two sites Bavaria, Germany to obtain high-resolution variations. Geoelectrical measurements (2D 3D) were conducted both over several years (2015–2018/2020) compared with (matric potential volumetric content) plots. greatest variations values that highly correlate found main rooting zone. Using ERT data, trends could be tracked dimensions, such interannual increase depth influence from events duration, rising going along decreasing moisture. results reveal good proxy seasonal Therefore, 2D- 3D-ERT recommended comparatively non-laborious small-spatial scale zone underlying subsurface forested sites. Higher spatial resolution allows better understanding supply trees, especially times drought.