A quantitative analysis of the root system of a mangrove, Sonneratia caseolaris (L.) Engler, with reference to the pipe model

Abstract

The whole root system of a Sonneratia caseolaris tree of the edge of a secondary mangrove forest was carefully excavated using a water-pump. All roots were sorted by diameter and weighed. The root-weight distribution showed that the medium (10-20 mm) and large (20-30 mm) classes shared a large portion of root weight. We analyzed the relationship between the root diameter (D) and the number of roots (F’). A significant inverse linear relationship was obtained for the F’-D relationship. The slope was not statistically different from -2.0, suggesting that the root system of this S. caseolaris tree follows the pipe model (Shinozaki et al., 1964a, b). The constant between total root weight (W_R) and the square of the stem diameter at ground level (D₀) was calculated. This proportional constant of S. caseolaris (0.025) was lower than that of X. granatum (0.051), which was formerly clarified to obey the pipe model theory (Poungparn et al., 2002). We discussed the application of the pipe model theory to estimate the root weight of mangroves from the W_R-D₀² relationship’s constant.