The southern region of Brazil is characterized by the dominance of extended grasslands. However, the landscape also contains different types of forests, such as Araucaria forests in the Atlantic Forest domain and Seasonal forests in the Pampa domain. This chapter addresses different elements of these forests in the South Brazilian grassland region. Based on a database of 139 forest sites with a total number of 675 tree species, all located in grassland-dominated landscapes, we analyzed the influence of current environmental and historical drivers on tree species richness and forest community composition. Our results show that only current environmental drivers, such as temperature seasonality, influence tree species richness, whereas both current environmental and historical drivers influence community composition. Further, we present examples of ecosystem functioning and services of these forests regarding water balance, carbon stocks, and soil productivity. Finally, we show landscape-level changes of forest cover. Across the region, forest cover increased in the last 35 years. However, this was driven by Seasonal forests in the Pampa region, while the Araucaria forests in the Atlantic forest region decreased in cover. We consider that the implementation of actions to restore mosaics of forests and grasslands in landscapes that were degraded is urgent. Despite their biological importance by harboring many floristic elements from different biogeographical affinities, the South Brazilian grassland region, including its forests, remains neglected in terms of biodiversity conservation.