Stockholm studio Jägnefält Milton has designed a leaf-shaped pavilion for a woodland site – taking advantage of a new Swedish planning stipulation that allows structures under a certain size to be built without permission.

Jägnefält Milton collaborated with the Berlin office of engineering firm Arup on the design of Forest Pavilion, a simple woodland shelter designed to exploit a building law introduced earlier this year.

The Attefallshus clause means planning permission is no longer required for structures with an area under 25 square metres and a height of less than four metres, so the architects designed a pavilion within these dimensions.

Forest Pavilion is designed as an oval platform with a matching roof made from lead. "It's a leaf, it's as simple as that," studio co-founder Konrad Milton told Dezeen.

Designs show a wooden platform with a patterned parquet floor that raises the base of the pavilion above the ground. According to the architects, all the timber needed for construction will be sourced during the site clearance.

"The wood came out of the material used directly from the site," said Milton, "and the reason for choosing a lead roof was that we wanted it to age in coherence with the site, the structure and the floor."

The leaf-shaped roof will be lifted above the platform on a single tapered column, supported by zigzagging cables that can be anchored to the ground by attaching a tether to a large boulder.

The diagonal cords between the roof and floor will also create a framework for a removable outer covering, allowing inhabitants to either open or close the space to the surrounding woodland.

Polyurethane sheeting was chosen as the lining for its waterproof properties – a material the architects claim has proved its effectiveness through its common use as a protective duvet covering for bed-wetters.

The pavilion is currently just a concept, but the team are seeking both a site and an investor to realise the project.

"So far we have no client for it, but anyone with a beech forest is welcome to contact us," added the architect.