The original Development Corporation design concept aimed for a 'forest city' and its foresters planted millions of trees from its own nursery in Newlands in the following years. As of 2006, the urban area had 20 million trees. Following the winding up of the Development Corporation, the lavish landscapes of the Grid Roads and of the major parks were transferred to the Milton Keynes Parks Trust, an independent non-for-profit charity which is separate from the municipal authority and which was thus intended to resist pressures to build on the parks over time. The Parks Trust is endowed with a portfolio of commercial properties, the income from which pays for the upkeep of the green spaces, a citywide maintenance model which has attracted international attention.