Juniperus bermudiana is a species of juniperendemic to Bermuda. This species is most commonly known as Bermuda cedar, but is also referred to as Bermuda juniper.
It is an evergreentree growing up to 15 m tall with a trunk up to 60 cm thick (larger specimens existed in the past) and thin bark that exfoliates in strips. The foliage is produced in blue-green sprays, with the individual shoots 1.3–1.6 mm wide, four sided (quadriform) in section. The leaves are scale-like 1.5–2.5 mm long (up to 4 mm long on strong-growing shoots) and 1-1.5 mm broad, with an inconspicuous gland; they are arranged in opposite decussate pairs, occasionally decussate whorls of three. Juvenile plants bear needle-like leaves 4–8 mm long. The seed cones are irregularly globose to broad pyriform, 4–6 mm long and 5–8 mm broad, soft and berry-like, green at first, maturing bluish-purple about 8 months after pollination; they contain one or two (rarely three) seeds. The male cones are 4–6 mm long, yellow, turning brown after pollen release in early spring.
Old growth trees survive and prosper in a Paget garden.
A threat to the continued existence of Bermuda's junipers arose in the mid-1940s when the species was attacked by two species of scale insects, Lepidosaphes newsteadi and Carulaspis minima, which were unintentionally introduced from the United States' mainland during the wartime construction of US airbases in Bermuda. By 1978, these parasites had killed 99% of Bermuda's junipers, some 8 million trees. However, the remaining 1% of the trees proved somewhat resistant to the scale insects, and efforts by Bermuda's Department of Agriculture, Fisheries and Parks to plant young junipers from this resistant strain throughout Bermuda have saved the trees from extinction.
In the 1950s and 1960s, the Casuarina (Casuarina equisetifolia, also known as Horsetail Tree and Australian Pine), native to Australia, was introduced into Bermuda to replace the Bermuda cedar's windbreak functions. However in Bermuda, casuarinas have proved to be highly aggressive, and no other plants are able to survive beneath them. Still, like the Bermuda cedar, the casuarina's foliage is resistant to wind and salt, and these features have made casuarinas popular with gardeners in Bermuda. Other species introduced in an attempt to replace the juniper forest included the Bay Grape (Coccoloba uvifera). Along with the Casuarina, the juniper's main introduced competitor for space is the Brazilian pepper (Schinus terebinthifolius).
The species is occasionally grown as an ornamental tree outside of Bermuda, and may have become naturalised on Hawaii and Saint Helena. It is reported that more than 6,500 of them were planted in Hawaii between 1921 and 1953, and that it has established wild populations there.
The Bermuda cedar forests that covered Bermuda fed and housed many species of bird that had evolved and adapted to live amongst them, and thus became endemic to Bermuda. With the loss of so many trees the populations of such species have plummeted to near extinction. These birds include the Bermuda white-eyed vireo, and a possible subspecies of eastern bluebird. Efforts by the public and the government have been made to boost their populations along with the populations of the Bermuda cedar. However the Bermuda cedar may take 200 years to reach full maturity, and the birds may not survive this long. With recent sea level rises some low lying old-growth cedars are being infiltrated with seawater and are beginning to die off.
It is known for its heavy, sweet aroma, useful and attractive reddish timber, significant role in Bermuda's history, and notable presence in Bermuda's historic homes.
When English settlers arrived in Bermuda, forests of Bermuda cedar flourished throughout the islands, and the species continued to thrive even as settlers developed the land. The wood was utilized by settlers for widely varying purposes including home, church, jail, and shipbuilding, interior woodworking, furniture construction, coffin-making, and export for sale. In addition, the cones were used by settlers as food for both themselves and their animals, and to prepare cedarberry syrup as a treatment for toothaches and coughs. Settlers also boiled the shoots in water to create an elixir for lowering fevers. Furthermore, the wood was found to repel moths and fleas as well as prevent mildew and rot, so many Bermuda residents used the wood to line closets and drawers.
The Featherbed Alley Printshop Museum, in the cellar of the Mitchell House, built ca. 1720, which features cedar beams, though the floor boards above are of then-more expensive, imported wood.
The wood was especially prized by shipbuilders. It could be worked as soon as it was felled, and was naturally resistant to rot and woodworms. It was as strong as oak, but much lighter, contributing to the speed and maneouverability for which Bermudian ships were noted and prized. Its abundance enabled Bermudians to turn wholesale to a maritime economy after the dissolution of the Somers Isles Company in 1684.
In 1627, in an effort to conserve Bermuda's juniper forests, the local assembly passed legislation to restrict export of Bermuda cedar for shipbuilding. In addition, between 1693 and 1878, the Bermuda legislature passed sixteen further acts placing restrictions on the uses of Bermuda cedar. Despite these Acts, the shipbuilding industry eventually denuded much of Bermuda's landscape by the 1830s. Only the dawn of the age of steam-driven, steel-hulled ships allowed the forest to recover.
Many historic homes in Bermuda feature interior woodwork and furnishings made from Bermuda cedar. Examples of these homes include the Mayflower House, Camden House, Tucker House, and Verdmont House, the latter of which, according to the Bermuda National Trust, contains the colony's finest collection of antique Bermuda cedar furnishings. Because it is now both scarce, and expensive, and it is featured in many grand homes, its scent has come to be associated with wealth.
Grows in shallow, calcareous soils on hillsides and along marshes and coastlines. Once formed almost pure stands with an estimated density of as much as 500 trees to the acre (Groves 1955). Fruits ripen in September and October (Britton 1918). Germination rates are good where the habitat allows, taking into account the vastly reduced adult population. The main seed disseminator seems to be the Starling, Sturnus vulgaris, which became naturalized in the 1950s,increased explosively in the 1960s, and is highly mobile. Natural self seeding occurs mainly in unmanagedcoastal scrubland and exposed hilltops where the otherwise dominant invasive flora is sufficiently stunted or sparse due to wind and salt spray exposure to allow germination and juvenile growthof junipers to occur. In such areas a new forest cover is gradually developing where the juniper is the dominant emergent tree. It is estimated that the natural pre-disturbance generation length is 25 years - this is based on the length of time taken for a naturally regenerating stand of trees to reach harvestable age.
Juniperus bermudiana underwent a catastrophic decline of almost 95% between 1946 and 1956. Over the last 30 years, the population has started to recover as a result of natural resistance in part of the remnant population and intensive conservation efforts. Invasive plant species still pose a significant threat. Juniperus bermudiana has an estimated generation length of 25 years so three generations is the equivalent of 75 years. Some of the causes of reduction are not reversible due to urbanization and habitat loss. This species is therefore currently listed as Critically Endangered. Provided that the recovery is maintained, future re-assessments after the three generation period has expired should result in downlisting.
In a ten year period between 1946 and 1956, almost 95% of the natural population was lost due to the effects of an introduced juniper scale (Carulaspis minima). Over the last 30 years a combination of residual resistance, reafforestation and, to a lesser extent, natural regeneration has led to an increase. The current population is estimated to be well over 10,000 adult trees, possibly as high as 25,000, which represents approximately 10% of its former population density in suitable habitat.
From the time that Bermuda was first colonized in 1609 Juniperus bermudiana has been used extensively for construction purposes and as fuel for cooking. The use was so extensive that by 1622 special legislation had to be introduced (Tucker 1970) to control the export of the islands most dominant tree species. Between 1693 and 1878, the Bermuda legislature passed sixteen further acts in order to restrict the uses of the juniper. Despite these Acts, the ship-building industry eventually denuded much of Bermuda's landscape by the 1830s. The decline of the ship building industry after 1900, combined with the replacement of local juniper timber for construction with cheaper imported timber from the U.S. and rural electrification, which precluded the need for wood as cooking fuel, enabled a full recovery by the early 1940s. However, it was once more devastated as a result of the accidental introduction of two coccoid scale insects in 1946 (Challinor and Wingate 1971).
The juniper scale (Carulaspis visci) and the oyster-shell scale (Lepidoscaphes newsteadi) were present on ornamental species of juniper which were shipped to the island from California, USA (Bennet and Hughes 1959). In the absence of natural biological controls and genetic traits for resistance the native J. bermudiana suffered rapid defoliation and death, reducing the population by 95% within a period of 10 years (Wingate 2001)
During the following decades the bare landscape was reafforested using exotic species. Casuarina equisetifolia was especially favoured for its rapid growth. Invasive broadleaf plant competitors (which create too deep a shade for seed germination or growth), are now by far the greatest factors limiting the junipers distribution and self-seeding potential. Likewise,germination of the naturalized Ficus retusa in rot hollows of old junipers (which leads to eventual overshading and strangulation) and overshading by taller growing invasive broadleaved trees, especially in sheltered valley situations,is now the major cause of adult mortality.
To add to the problems, J. virginiana and J. virginaina var. silicicola have been introduced to Bermuda from Florida, USA. Both taxa are resistant to the scale insects. They readily hybridize with J. bermudiana causing a depletion of the germplasm through hybridization and introgression (Adams and Wingate 2008) .
Urbanization is also a problem. Today Bermuda is recognized as one of the most densely populated isolated oceanic islands in the world with a mean human population density of five per acre and one third of the country is totally urban (Wingate 2001). About 20% of Bermuda's land area is now paved over with roads, parking lots, buildings and industrial yards. This trend is likely to continue unabated.
Ironically, the Bermuda juniper does best today in that approximate one third of the landscape that is maintained largely free of invasive plants in parks and gardens with extensive lawn areas. Most old pure strainjunipers that survived the great scale epidemic are found in cemeteries, parks and private gardens where it is now very much in vogue again to plant cedars because they are more hurricane resistant.
Although chemical control of the juniper scale was possible, it was avoided for safety reasons due to the high density of the human population. As a result of rapid natural selection of a trait for scale resistance, which must have survived in about 5% of the population, most seedlings now seem to be partly or totally immune to scale attack, and survive. This enabled intensive re-forestation efforts to begin about 1980 and the species has since recovered to approximately 10% of its former population density in managed parkland and garden habitat. (Procter and Fleming 1999, Wingate 2001)
Juniperus bermudiana is cultivated in gardens outside of Bermuda and some of this material has potential to supplement restoration programmes in Bermuda. Perhaps the biggest planting is in St Helena and on Ascension Island where seed was introduced during the mid-19th century to establish timber tree plantations (Adams 2008). Ironically on these islands J. bermudiana is now becoming an invasive problem.Juniperus virginiana has also been introduced on St. Helena so there is the potential for hybridization (Adams 2008).