Sustainable development, açaizeiro ( acaizeiro ) or Açaizal ( acaizal ) - Acai palm trees in the border or Rio Preguicas ( Preguicas river ), Maranhao state, Brazil. The acai palm ( Euterpe oleracea ) is a species of palm tree in the genus Euterpe cultivated for its fruit and hearts of palm - global demand for the fruit has expanded rapidly in recent years, and acai is now cultivated for that purpose primarily. They are tall, slender palms growing to more than 25 m (82 ft) tall, with pinnate leaves up to 3 m (9.8 ft) long.