Anothony Perrett from Caldicot Town Council in Monmouthshire felt so angered by the proposal to put a pitch up for sale that he decided to take direct action.
The proposal would see the Caldicot Comprehensive School pitch converted into a car park as part of a development for a new supermarket.
Education officials are considering action against Perrett, 29, who is currently in Copenhagen.
Perrett said: "I have lived in this area all my life and played on the rugby pitch when I was a pupil at the school. I want future pupils to have the opportunity to play on the pitch too."
With the help of friends the councillor planted the trees between dawn and 10.30am.
He is a forester and said he chose trees that would provide food and fuel for future generations, including crab apple, hazel and walnut.
Education leaders at the council have voiced their anger at the protest.
Caldicot School head teacher Susan Gwyer Roberts said: "I was very surprised to find 199 trees planted on our land. An action of this nature has put the children at risk as the pitch is now out of action."
The council are considering donating the trees to the Gwent Wildlife Trust.
Perrett has refuted claims the trees are a threat to children.
He said the biggest threat to the students were the councils plans to build a car park for 262 cars.
Earlier this year he draped a red banner over the rugby posts in protest at the proposed sell off.
The stunt earned him a nomination in the Welsh Artist of the Year competition.
Perrett will face trial in February on a charge of aggravated trespass after taking part in an anti-aviation protest at Southampton Airport.