The Cao Lan are a Tai-speaking ethnic group living in the Midlands of Northern Vietnam. Homegardens are an important component of their agroecosystem. The ecological structure of each homegarden of 17 household of the Cao Ngoi villge in Tuyen Quang province were described and modal patterns identifed. Most homegarden have organically shaped planting areas with indeterminate boundaries, polycentric planting patterns, and contain multiple species within the same bed or planting area ...