Assessment of The Potential of Canal-Side Trees for Bank Erosion Prevention: A Case Study of Tha Yai Subdistrict Municipality, Thung Song District, Nakhon Si Thammarat Province

Abstract

This study aimed to (1) survey tree species and evaluate the potential of riparian trees along the Pak Phraek Canal in Tham Yai Subdistrict, Thung Song District, Nakhon Si Thammarat Province, (2) examine the factors influencing their effectiveness in preventing riverbank erosion, and (3) compare local residents’ perceptions of tree potential. A mixed-methods approach was employed. Physical data of riparian trees were collected from 10 systematically sampled sites. Tree potential was assessed using a weighted scoring equation based on three criteria: (1) root system stability, (2) hydrological tolerance and erosion resistance, and (3) ecological and socio-cultural value. In addition, perception data were gathered from 63 canal-side households and analyzed using percentage, mean, standard deviation, and t-test. Results revealed that riparian trees were present in only 6 out of 10 sites. The most common species included Sandoricum koetjape, Dipterocarpus alatus, Calophyllum inophyllum, Lagerstroemia floribunda, and Alstonia scholaris. The overall potential score was at a moderate level ( 𝑥̄ = 3.40), indicating that riparian trees provide both biodiversity value and erosion control capacity. Native species with diverse root systems and tolerance to waterlogged conditions-such as Hopea odorata, Barringtonia acutangula, Syzygium cumini, and Lagerstroemia spp. were identified as the most suitable for riverbank stabilization. Local residents demonstrated high awareness and understanding of the ecological and socio-cultural functions of riparian trees. Root architecture and hydrological tolerance were found to significantly influence tree potential (p ≤  0.01). The findings highlight the importance of selecting native, root-stable species for sustainable riparian restoration and community-based conservation.