Matthew Williams was not allowed to speak in the case because of his age, but fellow eco-warriors spoke on his behalf at the hearing before Mr Justice Astill.
Epsom and Ewell Borough Council had won an eviction order against the 20 protesters who moved into a park in the centre of Epsom after plans were agreed to fell trees for a road scheme.
Mr Justice Astill granted leave to appeal against the order "in the interests of justice" because it was possible that the eco-warriors had a case to argue.
The eco-warriors will be able to stay in thetree houses in the silver birches until after the Court of Appeal rules on the case on 1 October.
Matthew arrived at court with shoulder-length hair beneath a military hat and camouflage trousers and jacket. Afterwards he said: "It was really boring. I was not allowed to say anything. I wanted to tell him how much I love the green park and how much I want to save the silver birches.
"All my friends come to play with me there and I don't want that to come to an end because the trees have all been chopped down to make a road."
Matthew lives with his mother, Lorraine, and brother, Luke, 14, in the tree house. He dropped out of school when he was eight and cannot read or write. Although Matthew celebrated his 11th birthday only last week he is a veteran eco-warrior, having been at high-profile protests at Kingston and Crystal Palace.
His mother said: "Our way of life might seem strange to some people but I don't think it is doing any harm to anyone, least of all my children. All of us at the site believe in what we are doing. Matthew understands the value of the park as a place everyone should be able to enjoy."
Nigel Veal, 37, an English graduate from Epsom, is helping Matthew to learn to read and write. Mr Veal, who met Matthew when he took food to the protesters, said: "This is a public park which the council is trying to turn into a road scheme and destroy for ever."
He hoped to represent Matthew at the appeal as his legal guardian, when he would bring up the fact that Britain was a signatory to the Rio Earth Summit in 1992, which decided children should have a say in environmental issues.