The trees are not ornamental; they grow from an earthen bank, roughly a metre high, that traces a near-circular enclosure measuring approximately 17 metres north to south and 21.5 metres east to west. The bank itself has been supplemented over time with clearance material, the stones and debris that farmers moved off surrounding fields to make grazing easier. That accumulation is mundane enough, but what lies beneath it is a different matter.

Enclosures of this kind are found across Ireland and are generally understood to be early medieval in origin, though many remain undated without excavation. They are sometimes called raths or ringforts, terms that describe a broadly similar form: a roughly circular area defined by one or more earthen banks, originally intended to enclose a farmstead and its outbuildings, offering both a degree of security and a visible mark of status in the landscape. The addition of field clearance to the bank at Ballymacgibbon is typical of what happens to such features across generations; a structure that nobody quite demolishes gets quietly pressed into service as a convenient dumping ground, its original character slowly buried under practical necessity. The trees that have since colonised the bank give the whole thing an accidental dignity, a circle of growth that picks out the old boundary in a way no planned planting could.