Trees and plants have played an integral role in the development and maintenance of socio-cultural and religious systems globally throughout history. They have been used for subsistence, are culturally modified, are imbued with or considered to hold preexisting sacred, magical, and protective qualities, and are revered and embellished though a range of ritual and religious practices, all set within complex belief systems. Throughout the Greater Asian region, trees have been revered and worshipped by both major religious institutions and their practitioners, and by local indigenous and ethnic groups holding animistic and nature-based religious beliefs and practices. At times trees are the locus for plural and multiple beliefs and practices, a point where major religions and local cosmology and ritual practices merge. In Greater Asian this is most apparent between Buddhism, Hinduism, and local spirit or nature-based worship. The past, present, and future importance of trees as sacred entities and their role within natural and socio-cultural landscapes and religious systems cannot be overestimated; in supporting cultural practices and traditions, as situated within broader sacred landscapes, but also playing a major role in supporting essential ecosystem services within both human built landscapes and natural ecosystems. This paper will provide examples of religious and sacred cultural uses and values in trees, derived from ethnographic and investigative fieldwork across the Greater Asian Region including Nepal, Thailand, Lao PDR, and Japan. This paper will introduce this research as part of a broader project investigating living sacred nature and sacred landscapes in Greater Asia. It will conclude by considering how cultural briefs and practices in nature have supported cultural continuity and ecological management over time and will consider how today, situating sacred nature as a form of cultural heritage, can be used to promote sustainability outcomes for people, culture, and the sacred-natural landscape.