The royals are on a 10-day visit to southern Africa, their first official tour as a family.
In Botswana, Harry joined 200 schoolchildren on Thursday morning as they planted trees in the Chobe Forest Reserve.
The Duke of Sussex planted a baobab, a tree that is “severely under threat across Africa,” according to an Instagram post that was accompanied by a photo of Harry kneeling next to a seedling and high-fiving one of the children.
The seeds were grown by the children in recycled milk tins, using fertilised soil from an elephant orphanage, the post said.
”If you look after nature, it will look after you,” Harry was quoted as saying.
Later Thursday, he is scheduled to visit an HIV project and dedicate an area of the Chobe National Park to the Queen’s Commonwealth Canopy, a network of forest conservation initiatives.
He will then travel to Angola, where he will spend the evening in a de-mining camp run by a British charity in the town of Dirico.
Harry’s three days in Angola will see him walking in the footsteps of his mother, the late Princess Diana.
He will visit the location where an iconic picture of her was taken at a de-mining site in 1997 and an orthopaedic centre she visited that will be renamed after her.
Meghan is spending on Thursday in the South African city of Cape Town, where she will take part in a breakfast dedicated to women in public service.