Cacti are cultivated on 2.6 million ha across the world, and mostly used for forage, fodder and fruit production in both subsistence and market oriented agriculture. Despite their ecological, economic and social importance, Opuntia (cactus pear) continues to receive limited scientific, political and media attention. Well-maintained cactus plantations generate positive externalities and environmental goods and services: they can play a major role, not only in terms of biodiversity enhancement and carbon sequestration, but with regard to landscape and nature conservation, mitigation of soil erosion, water protection and cultural heritage. Cactus crop is easy to establish and to maintain and has various utilizations able to improve the livelihoods of rural poor. It produces good quality fruits for local or international markets; cactus young cladodes (nopalitos) are used as vegetable and most of young and elder cladode provide forage and fodder which help also in reducing water consumption by 70%. The paper review the us of cactus trees in rangelands. Production of 50 T DM/ha/year are reported in intensive cultivation system (80 T of manure, 160,000 plants/ha) in rainfed conditions in North East of Brazil. In arid regions of Tunisia (200-250 mm rainfall, no fertilizers), 14.5 T DM/ha/year, sufficient to cover the needs of 15 sheep while 2 ha of rangeland are needed to support 1 sheep (35 times higher). A cactus orchard productivity of 20 T DM/ha/year is sufficient to sustain 4-5 cows per year. In the same area, 15 ha of rangeland is needed to sustain one animal unit (60-75 times higher). In fruit-forage orchard and under very harsh conditions, the productivity is around 1.5 to 2 T DM/ha/year.