It is a shrub or small tree growing to a height of 6m (20ft) and a trunk diameter up to 50 centimetres (20in). The leaves are evergreen, needle-like, in whorls of three, glaucous green, 4–10 millimetres (1⁄4–1⁄2in) long and 1–3mm broad, with a double white stomatal band (split by a green midrib) on the inner surface. It is dioecious, with separate male and female plants. The seed cones are berry-like, green ripening in 18 months to orange-red with a variable pink waxy coating; they are spherical, 6–9mm diameter, and have three or six fused scales in one or two whorls of three, the three larger scales each with a single seed. The seeds are dispersed when birds eat the cones, digesting the fleshy scales and passing the hard seeds in their droppings. The male cones are yellow, 2–3mm long, and fall soon after shedding their pollen in early spring.[4][5]
Subdivisions and habitat
Three subdivisions are accepted.[2] They vary in form and habitat.[3]
Juniperus brevifolia subsp. brevifolia – a small to medium tree found between 300 and 1000 metres elevation on Corvo, Faial, Flores, Pico, Santa Maria, Sao Jorge, Sao Miguel, and Terceira.[3] It grows in a variety of habitats, including Juniperus–Laurus azorica forest, Juniperus–Ilex perado subsp. azorica forest, in pure Juniperus woods and Juniperus–Sphagnum woods, and in pioneer scrubland on lava flows with Erica azorica, Calluna vulgaris, and Vaccinium cylindraceum.[1]
Juniperus brevifolia subsp. maritimaR.B.Elias & E.Días – an erect shrub or small tree native to coastal scrubs below 100 metres on Flores, Terceira, Pico and São Jorge,[3] often growing with Myrica faya and Erica azorica.[1]
Juniperus brevifolia var. montanaR.B.Elias & E.Días – a small prostrate shrub common in mountain scrubs and blanket bogs between 850 and 1500 metres elevation,[3] often with Calluna vulgaris.[1]
Conservation
This is a vulnerable species in its native range due to a combination of historical felling for the valuable wood and competition from invasive introduced plants.[1]
On the island of Graciosa, Juniperus brevifolia has gone extinct, and on the other islands, it remains endangered.[6] The decline in population is due to habitat fragmentations of its preferred habitat (laurel forest) caused by island colonization and grazing pressures.[6][7]
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