By Carolyn Cowan BANGKOK, Thailand — Standing on a coastal boardwalk overlooking the upper Gulf of Thailand, Wisut Leksomboon points to two mature mangrove trees whose branches intertwine like lovers’ limbs. “We found that by planting two seedlings close together, they can offer each other support as they grow. These trees are about 30 years old,” Wisut tells Mongabay during a visit to the Mangrove Nature School in Bang Kaew, a village roughly two hours’ drive south of Bangkok in Samut Songkhram province. As a founder of the eco-school and a local leader, Wisut has worked for more than three d…