Remote sensing imagery suggested that mangrove progression
differed strongly between eastern and western sites: in the
east, mangrove progress in the selected river mouths has been
in the order of 140e1200 m over the period of about 31 years,
or approximately 5e38 m y1. In the west, however, equally
large mangrove forests increased only little in the seaward direction:
10e90 m over 31 years or less than 3 m y1. Mean
annual progression rate was significantly higher in Pak Phanang
Bay, Nakhon Si Thammarat than in the other three sites
(Fig. 2).