Pittosporum undulatum Vent. Pittosporum undulatum Sweet pittosporum ( ) is native to eastern parts of Australia. An evergreen tree with attractive fragrant flowers, sweet pittosporum has been introduced widely as an ornamental plant to North America, southern Africa, and many oceanic islands. It is reported to be an environmental weed in its native Australia spreading beyond its native range. It is known as an invader of many tropical and subtropical mountain forests and in warm temperate regions of both hemispheres and many islands. Seeds are predominantly dispersed by birds and deposited at the base of trees where they germinate soon forming a close dense canopy dominating native vegetation. Seeds are not stored in the soil year to year and are sensitive to temperatures as low as 90 degrees C. Prescribed burns have been recommended as a control option; seed banks are destroyed, growth rates reduced, as are seed dispersal and seedling survival. Photo Credit: Forest and Kim Starr [link] Sweet pittosporum was introduced to the Azores as a hedge plant to protect orange tree plantations reportedly in the early 19th century. It is Sweet pittosporum is known to have spread to native forests in Jamaica listed as being one of ten most common woody plant species (trees and from the Cinchona Botanic Garden in 1883. The secondary forests that shrubs) present in Azorean native forests and a major threat to Azores are dominated by this introduced species consist of shrubs and early- Morella faya Laurel azorica native biodiversity. On San Miguel Island it is one of several plant species successional forest tree species. The displacement of native understorey plantReference: species has been partially attributed to allelopathic effect. that dominates native forests of and . Bellingham P. J., Tanner E. V. J., Healey J. R., 2005. Hurricane disturbance accelerates invasion by the alien tree Pittosporum undulatum in Jamaican montane rain forests. J Veg Sci 16:675–684 Gleadow, Roslyn M.; Narayan, Indira (2007) Temperature thresholds for germination and survival of Pittosporum undulatum: implications for management by fire. Acta Oecologica. 31(2). MAR-APR 2007. 151- 157. Hortal, Joaquin; Borges, Paulo A. V.; Jimenez-Valverde, Alberto; de Azevedo, Eduardo B.; Silva, Luis, 2010. Assessing the areas under risk of invasion within islands through potential distribution modelling: The case of Pittosporum undulatum in Sao Miguel, Azores. Journal for Nature Conservation (Jena). 18(4). DEC 2010. Click here to view archives of previous weeks’ species 247-257..