Comparison of water-use by alien invasive pine trees growing in riparian and non-riparian zones in the Western Cape Province, South Africa

► Self-sown pine trees invading riparian zones used 36% more water than trees in non-riparian areas. ► Greater water-use by riparian pines was a result of larger tree sizes than higher sap flux densities. ► Trees in both habitats closed their stomata under high atmospheric evaporative demand. ► Stand transpiration was accurately predicted by a Penman-Monteith type model in both habitats.