A simple and cost-effective method for cable root detection and extension measurement in estuary wetland forests. Estuarine, Coastal and Shelf Science, 183(Part A), pp. 117-122. (doi:10.1016/j.ecss.2016.10.029) This is the author's final accepted version.There may be differences between this version and the published version. You are advised to consult the publisher's version if you wish to cite from it.http://eprints.gla.ac.uk/157326/ This work presents the development of a low-cost method to measure the length cable 22 roots of black mangrove (Avicennia germinans) trees to define the boundaries of 23 central part of the anchoring root system (CPRS) without the need to fully expose root 24systems. The method was tested to locate and measure the length shallow woody root 25systems. An ultrasonic Doppler fetal monitor (UD) and a stock of steel rods (SR) 26 were used to probe root locations with-out removing sediments from the surface, 27 measure their length and estimate root-soil plate dimensions. The method was 28 validated by comparing measurements with root lengths taken through direct 29 measurement of excavated cable roots and from root-soil plate radii (exposed root-soil 30 material when a tree tips over) of five up-rooted trees with stem diameters (D130) 31 ranging between 10-50 cm. The mean CPRS radius estimated with the use of the 32 Doppler was directly correlated with tree stem diameter and was not significantly 33 different from the root-soil plate mean radius measured from up-rooted trees or from 34 CPRS approximated by digging trenches. Our method proved to be effective and 35 reliable in following cable roots for large amounts of trees of both black and white 36 mangrove trees. In a period of 40 days of work, three people were capable of 37 measuring 648 roots belonging to 81 trees, out of which 37% were found grafted to 38 other tree roots. This simple method can be helpful in following shallow root systems 39 with minimal impact and help map root connection networks of grafted trees.