Bosk is a mobile forest consisting of 1200 trees in 800 containers, moved throughout the city of Leeuwarden over a period of 100 days with the help of volunteers. Each container is transported using special hand carts, with the caravan of trees covering 3.5 kilometers through the city and settling in various squares. The project promotes engagement with green spaces and strengthens social connections in the city.

The containers house trees of two sizes: twenty-year-old trees with a trunk circumference of 30-35 cm and ten-year-old trees with a trunk circumference of 16-18 cm. These are mainly native species suitable for the Frisian environment. After the 100-day period, the Bosk trees were stored at the municipality's depot and largely planted in and around Leeuwarden. The project has served as inspiration for greening initiatives in other cities, both nationally and internationally.

The reactions from city residents were mostly positive, despite the temporary limitation of parking spaces and traffic flow. Bosk transformed busy streets into green havens of tranquility, receiving much appreciation. The project illustrates the value of green spaces and initiates discussions about mobility, culture, and nature. The desire to permanently preserve the trees underscores the importance of green spaces in the city.