Scooting on his electric skateboard through a southern Mexico City neighborhood, Arturo Hernandez spots a likely target for his next action and uploads a photo to social media calling his followers to help. A couple of days later, he and several of them are swinging sledgehammers at a thick layer of concrete suffocating the roots of an ash tree when a pair of police officers arrive and ask to see a permit.
"We do not need permits to liberate the tree," Hernandez tells one of the officers with a grin. "It's as if you asked me to have a permit to pick up trash from the street."
The officer responds with his own smile, turns to his partner and they walk away. The hammering resumes.
This is El Ejercito de Arboles - The Tree Army - and Hernandez is El Comandante, its commander. Hernandez, a community activist who developed a following over years of tackling the city's problems in humorous online posts, launched The Tree Army in May in response to growing complaints from his followers about vandalized trees in their neighborhoods. Its mission is to protect and improve Mexico City's urban forest, whether it's chipping away at unauthorized concrete, confronting illegal cutting or planting trees in areas of need.
"I always tell people, if we can't take care of the tree in front of our home, how can we expect to save a place like the Amazon?" Hernandez said.
