This study was undertaken in an evergreen forest nearby the Medicinal Plant Garden in Doi Suthep-Pui National Park, Chiang Mai Province, northern Thailand. The sampling site for the submerged succession experiment was located in the same area as for the terrestrial experiment. The stream was 30 cm to 1 m wide, 15 cm to 45 cm deep and passed through secondary forest. Unpolluted water flowed throughout the year, with flooding during the rainy season. The stream comprised a stony, sandy and gravel bottom.