I'm writing a proposal that contrasts systems with two different geometries. I'm looking for a word or short phrase (preferably non-technical), that would describe one of the geometries, which is space analogous to the space under a forest canopy and among the trees plus the gaps in the canopy and clearings, i.e. all the air space in the forest.

For comparison, the other system I'm describing is the vertebrate circulatory system, which can be described as a tree of vessels.

Some words I've considered are *anastomosing* and *reticulum*/*reticulated* but both words miss some aspects of the system I'm trying to describe (the clearings/gaps in the canopy) and also describe some parts of the system I'm contrasting it with (the vascular system).