According to V. Narayanan, the proverb 'One tree is equal to ten sons' found in Indian tradition can 1 inspire today's ecologist behaviours in India. Actually, the first occurrence of this phrase is not found in the Matsyapurāṇa (154.512), but in the unpublished chapter 158 of the original Skandapurāṇa (SP), probably composed near the end of the sixth century in the centre of North India. In their section about trees, Dharmanibandha authors quote, inter alia, this proverb, some verses in chapters SP158 and other sources, including lost works, which all suggest the existence of a particular ritual dedicated to trees, which is neither the gift nor the planting of a tree, but its adoption as a son. What is the aim and the particularity of this ritual? How can one adopt a tree? What are the differences between the procedures described? Is it possible to sketch a historical survey of this ritual? By studying how Dharmanibandha authors handle their tree chapters, the article offers a new assessment on the value of each Nibandhas work and enables reliable identification of sources dealing with tree adoption. Once these sources are determined, their comparative study first reveals that one can save one's ancestors through tree adoption which could be understood as another soteriology. Then, working through the complexity of the ritual procedures, it establishes a relative chronology of the different occurrences of the tree adoption. Finally, it tries to trace the continuation of this ritual in later sources, showing its impact on Indian culture.