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 × cistena Prunus × cistena Prunus × cistena, the purple leaf sand cherry or dwarf red-leaf plum, is a hybrid species of prune-cherry, the result of a cross between "Prunus cerasifera" (cherry plum or myrobalan plum) and "Prunus pumila" (sand cherry). A leggy bush or shrubby tree, it typically reaches a height of 1.5–2.5 meters and has a useful life of 10–20 years. The fruit are edible, if strong-tasting. Some people make jams or preserves from them. It is not advisable to eat the pits. Frost-tolerant, purple leaf sand cherries can be grown up to USDA Hardiness Zone 2. Commercial specimens are