Considering the economic importance and acreage of European permanent grasslands, it is important to maximize the yield and quality of the forage they produce through optimized management. An important driver of losses in forage yield and quality is climate change, especially due to increasing drought periods during the vegetative season. Agroforestry for forage production could be a promising solution to provide additional tree-based forage, especially during summer, when risks of droughtinduced decrease in forage production are the highest. Indeed, many tree species can be more resistant to drought than herbaceous species, because they can access water in deeper soil layers due to their deeper root system. Leaves of specific fodder tree species, such as Fraxinus spp., Morus spp. and Salix spp. can have excellent digestibility and nutritional value for livestock. Moreover, many fodder tree species achieve their maximum leaf production over summer and they can maintain high leaf forage quality until late summer/early autumn, when forage yield, quality and digestibility of herbaceous species generally decrease, above all during drought periods. The abundance of condensed tannins in fodder tree leaves can also provide additional benefits for ruminant by increasing intestinal protein availability, protecting against bloat and decreasing gastrointestinal parasites. Furthermore, condensed tannins have also been shown to help decrease ammonia production and reduce methane emission during rumination. Beside direct positive impacts on animal nutrition, health and gas emissions, agroforestry systems for forage production also provide multiple ecosystem services, such as increase in biodiversity (e.g., plant, insect and bird diversity) and carbon storage, as well as decrease in nutrient leaching. Nevertheless, a more holistic and interdisciplinary study on agroforestry systems is warranted, since the complex interactions among specific management techniques, productivity, sustainability, and various ecosystem services associated with agroforestry for forage production have been poorly investigated. The AgroForageTree project aims at evaluating the potential of five fodder tree species (Table 1) to provide supplementary tree-based forage (in addition to grass-based forage) in late summer-beginning of autumn along a climatic (900 to 1600 mm) and altitudinal gradient (450 to 800 m) composed of seven sites with different livestock categories (horses, cows, goats). The project is organized according to four main objectives, which will be presented in the poster together with the adapted methodology: 1) Monitoring the survival, annual growth, carbon uptake, water-use efficiency and photosynthetic activity of five selected fodder tree species in different permanent grassland sites across an altitudinal and climatic gradient. 2) Determining leaf production, leaf nutrients content and digestibility of the five fodder tree species and their variation along the growing season across the altitudinal and climatic gradient. 3) Investigating the impacts of fodder tree hedgerows on ecosystem biodiversity and services along the years after the establishment of the agroforestry system. 4) Assessing the palatability and selection for the five fodder tree species by different livestock categories, as well as methane emissions, nutrient absorption and digestibility resulting from the tree-grass diet.
