Chadchart was speaking after joining Canadian Embassy staff to plant Bodhi and Ironwood trees at Vachirabenjatas Park in Chatuchak district.
He said that up to 700,000 trees had been planted under the project so far. He added that City Hall is seeking saplings and places to plant them so people could participate in the project.
"A liveable city is a city with well-cared-for trees," he said.
All 50 district offices across Bangkok have tree specialists to advise officials on how to trim trees properly and tackle any related disputes, Chadchart said.
He also highlighted his "Bangkok 15 minutes" policy, which aims to create small public parks so that all Bangkokians are within a 15-minute walk of a green space.
"A good public park is one close to people's residences," he said.