"Brush Arbors" of various sorts are very likely global in origin - independantly arising where ever there was a want/need and readily available materials. In the SE US they are an important element of Native American religious practices, with various rituals associated with construction, refurbishment, utilization and decoration. The tradition was carried westward with peoples torn from theie homelands during the "removals" of the 1800s. Ceremonial uses aside, they are a delightful repreive from the scorching heat of hot day, and conducive of great chat and comaraderie.