A structure for creating housings for setting trees into the ground includes a plurality of modular elements (2), each one having an upper face (21) and support legs (22), the elements being associable with one another so as to obtain an upper surface (P, M), which is substantially continuous, and a lower volume (V), which is substantially empty. Tubular extensions (24), which at least partially cover the legs (22), according to their length determine the depth of the housing and hence the dimension of the volume (V). The tubular extensions are held in position, before the subsequent positioning of the modular elements, by a framework, which is provided with supports (32) adapted to be inserted into the upper mouth of the tubular extensions.
