The objective of this work is to identify environmental and ecosystem services provided by trees from the perception of family farmers in the Serra dos Tapes, southern Rio Grande do Sul, Brazil, addressing the relevance of species for ecosystem sustainability of family farming. Environmental and ecosystem services offered by the tree flora of semi-deciduous submontane forest are presented according to the perception of farmers who use accumulated knowledge for social, cultural and economic reproduction in family farming. Four farmers were selected for their remarkable knowledge related to the agro-ecosystem and the local floristic composition, and they answered semi-structured interviews about 115 native tree species relating them to environmental and ecosystem services. The knowledge of farmers regarding the importance of forest cover for beekeeping, agroforestry system installation, source of biological materials for environmental recovery, conservation of hydric resources and for feeding mammals and birds was evidenced.