Jersey the island. The species is the subject of an ongoing programme to save it from extinction in Jersey via a collaboration between States of Jersey, Durrell Wildlife Conservation Trust and Jersey Amphibian and Reptile Group (JARG), with support and sponsorship from several other organisations. The programme includes captive breeding and release, public awareness and habitat restoration activities. Trees generally considered native are the alder ("Alnus glutinosa"), silver birch ("Betula pendula"), sweet chestnut ("Castanea sativa"), hazel ("Corylus avellana"), hawthorn ("Crataegus monogyna"), beech ("Fagus sylvatica"), ash ("Fraxinus excelsior"), aspen ("Populus tremula"), wild cherry ("Prunus avium"), blackthorn ("Prunus spinosa"), holm oak ("Quercus ilex"),
Prunus serrulata of the world. Numerous cultivars have been selected, many of them with double flowers with the stamens replaced by additional petals. In cultivation in Europe and North America, it is usually grafted on to "Prunus avium" roots; the cultivated forms rarely bear fruit. It is viewed as part of the Japanese custom of Hanami. There are several varieties: Some important cultivars include: Prunus serrulata Prunus serrulata or Japanese cherry, also called hill cherry, oriental cherry or East Asian cherry, is a species of cherry native to China, Japan, Korea and India, and is used for its spring cherry blossom displays