These tree circles exhibit a wide range of variation along spatial dimensions of containment, presence, boundary and creep, placement, elevation. The trees themselves experience adaptation, deformation, strangulation, presence and absence. People (both pedestrian and civil) engage with these spaces through adoption, recruitment, adornment, repair, replacement, often leaving traces of layered repairs and even layered replacement. Planners respond to the contextual hardscape with circle types, repetition, replacement, blending/disguising/hiding. Plants and soils respond opportunistically, defiantly, reluctantly and with limited horizontal agency and near-unlimited vertical agency. Sometimes the absence of a tree circle reflects a kind of permission, while other times it reflects negligence.
The surrounding pavements and pavement boundaries at times acknowledge and at other times define the tree circle in the absence of a tree grate. Tree circles act as places and non-places formerly, presently, and potentially.
In contrast to the participant views of street level vistas and the immersive shelter of tree canopies, the tree circle lends itself to a moment of spectatorship, a looking onto something from a higher vantage point, a focusing in on a detail that integrates in the experience of place.
Tree circles mark a porosity of the hardscape. Their absence or the patching over of a tree circle marks the barrier between the soil and the street. They connect the dots of the canopy and reflect the view of what a tree offers to the construction of place. Tree circles are an element of civic heritage because they are a mood-crafting element of the landscape image of the street. They pattern in ways that mark the passage of time in a place with continuity, discontinuity, salience and backgrounding.