True cedars (Cedrus sp.) Fam. Pinaceae
Cedrus libani, Cedar of Lebanon; C. atlantica, Atlas Cedar; C. deodara, Deodar; C. brevifolia, Cyprus Cedar
True cedars are well represented in both large and small Devon gardens and parks, ranging from the impressive Cedar of Lebanon, a recurring feature of manor house and gentry lawns, to the popular blue form of the Atlas cedar of more modest gardens, an asset contributing significantly to urban and rural street scenes.
|Cedrus atlantica Glauca in Magdalen Road, Exeter.||Cedrus atlantica Glauca in Colaton Ralegh.|
Cedars are notable in Devon at some easily accessible sites, such as National Trust properties and Exeter University.
The National Trust abounds in stately homes, where the Atlas Cedar is most frequent (25), somewhat less so, the Deodar (15) and Cedar of Lebanon (10). Single specimens of the Cyprus Cedar are to be found at Arlington Court and Knightshayes.
At Exeter University, a more recently developed site, the Atlas Cedar is most frequent (21), the blue Atlas Cedar, Cedrus atlantica ‘Glauca’ (18) and the Deodar (16), slightly less so. Cedar of Lebanon trees are considerably fewer (8) and matched by the Cyprus Cedar, which is surprisingly abundant (8), being in general a less attractive and less favoured species.
The Tree Register of the British Isles, TROBI, records sizes of significant trees which must be reaching the end of their normal life span, indicating longevity and potential size of Cedar trees in Devon. Cedar of Lebanon appears to achieve greatest age, the Deodar generally the least, while the Atlas Cedar blue is longer lived than the green.
Champion status is found at a number of National Trust properties where some trees are county champions, such as the Cedar of Lebanon at Knightshayes, height 30m, girth 515cm, as measured in 2003.
There are many privately owned gardens and parks with a wealth of majestic Cedars.
- The Cedar of Lebanon at Poltimore House, Exeter, height 35m, girth 452cm, measured 2003.
- The Atlas Cedar at Lindridge Park, Newton Abbot, height 21m, girth 452cm, measured 1989, and at Heanton Satchville, Great Torrington, height 32m, girth 298cm, measured 1997.
- The Deodar, at Bicton Park Gardens, Exmouth, height 31m, girth 556cm, measured1968, an ‘historic champion’, an old record of a tree which has since died; Shobrooke Park, Crediton, height 33m. girth 512cm. measured 2006, and Castle Hill, Filleigh, height 33m., girth 420cm. measured 2007.
- The Golden Deodar, C.deodara ‘aurea’, Endsleigh, Tavistock, height 28m., girth 314cm., measured 2004, is both a county and national champion.
- The Cyprus Cedar, C. brevifolia, a much smaller, unspectacular tree, planted less frequently, is county champion at Bicton Park Botanical Gardens, height 15m, girth 192cm, measured 2001.
DGT tree recording is concerned with more modest specimens found largely in domestic gardens and parks in which cedars are well represented. The popularity of the blue form of the Atlas Cedar, Cedrus atlantica ‘Glauca’ is evident. It is ironic that in our early work recording the distribution of Cedar of Lebanon in the county, we encountered the difficulty of distinguishing between the Lebanon and Atlas cedars. It has been said it is a brave man who can confidently distinguish between the two in all instances.
Mature cedar tree profiles
| Atlas cedar Cedar of Lebanon Cedar of Lebanon (old)|
Cedrus atlantica Cedrus libani Cedrus libani
True Cedars are tall, evergreen trees, generally pyramidal in shape, tending to become flat topped with age. Shoots are of two types, long shoots of unlimited growth which contribute to overall tree architecture, and dwarf, spur shoots of limited growth. .
Long shoots, branches, of the Cedar of Lebanon develop distally into level flat plates, those of the Atlas ascend slightly but then flatten and become irregular at the ends, while Deodar branches droop elegantly. The Deodar in early years is shapeless, but becomes very striking when older.
Leaves are short, needle like, stiff, except in the Deodar, where they are silky.
Dwarf spur shoots, of limited growth, are each subtended by a transient leaf which is shed in the first or second year. Spur shoots bear leaves in apparent successive whorls. Leaves are stiff, up to 2.0-2.5 cm long in the Cedar of Lebanon and the Atlas Cedar, much shorter to 1.5 cm on older trees of the Cyprus Cedar, but long and silky and up to 5 cm in the Deodar.
A distinctive feature of the Atlas Cedar is a small translucent spine at the leaf tip.
|Cedrus atlantica at Gittisham.||Cedrus atlantica - foliage and cones on a tree at Exeter |
University's Streatham Campus.
| Cedrus deodara - young tree in|
| Cedrus deodara - young tree in|
parkland at Escot.
| Cedrus deodara - erect stem |
with pendant branches.
Cones, technically unisporangiate strobili, but often erroneously, even in the most erudite circles, called flowers, develop on dwarf/spur shoots and mature in autumn. The microsporangial, (male) cone, is simple bearing spirally arranged scales with pollen sacs. The megasporangial (female) cone is compound bearing spirally arranged bract scales, each with an axillary ovuliferous scale (evolved from an axillary branch) bearing two ovules. In cedars the bract scale is minute and hardly visible. Unlike many Pinacean relatives, the pollen grain is unwinged; it is disseminated by wind and germinates on a one-sided flange of the nucellus. Cones are upright, there is no pollination drop, so the cones do not become post pollination geotropically re-orientated, as in the pines. Mature female cones are hard, barrel shaped in all, flat topped in the Lebanon and Deodar, sunken topped in the Atlas, and small with a distinct beak in the Cyprus. Cones are not formed on young trees, ex. the Lebanon only after about forty years. Climatic conditions in the UK are not conducive to production of viable seed. The Atlas, maturing in September, is most likely to give viable seed, but Lebanon, in October, is less likely. In most gardens viable seed production is unlikely. Seeds are winged and viable only after slow drying
GEOGRAPHIC DISTRIBUTION AND HISTORY
The four apparent species of the genus Cedrus seem to be closely related, possibly originating from one species which ranged from the Himalayas in the east, to the Atlas Mountains in the west.
However the fossil record is insufficient to endorse conclusively the idea of a continuous distribution, but does indicate a wide discontinuous distribution in the Old World in the Upper Tertiary. Subsequent climate change and economic exploitation have resulted in the contracted ranges seen today.
Lebanese Cedar - Cedar of Lebanon
This species has a natural range of the eastern coast of the Mediterranean, in mountains growing 1400-2000m above sea level.
In antiquity the Phoenicians, a maritime trading nation, were dominant in the Levant for nearly three millennia (2600BC-138AD), responding to the needs of settlements, particularly timber for buildings, ships and fuel. Conifer resinous wood was in demand generally for pitch, tar and resin, Egypt being one of the largest timber consuming countries. The Cedar of Lebanon was prized particularly for its durability and fragrance; its exceptional size was significant for major buildings such as temples. Oil distilled from cedar wood was recognised as an antiseptic, used as a basis for cough medicines and ointments; it was exported to Egypt for embalming the dead.
A consequence of trade was that by Roman times the forests of Cedar of Lebanon were already restricted to the upper slopes of mountains. The denudation of forests, followed by torrential rain, led to soil erosion, leaving scoured mountain sides barren, and an entire ecosystem change. Today, natural regeneration is hampered by a slow rate of soil recovery, summer drought and grazing by sheep and goats.
Extensive felling over thousands of years led to population decline. It is now infrequent in Lebanon, twelve remaining stands, approximately 1.700ha; the girth of one tree on Mt.Lebanon measured 1050cm in 1995. The species is more abundant in Syria (approximately 20,000ha) and more so in Asian Turkey (Anatolia), in particular the Taurus Mountains (approximately 150,000ha).
The reputedly oldest trees are now found in the Taurus Mountains, where in poor soils, small and gnarled trees, have an estimated age of up to one thousand years. In Britain, the more favourable soil and climate accelerate growth, lead to girth measurements in the order of 330-350 cm, but diminish life span to about 200-250 years.
Arabs of all sects attribute intelligence and eternal life to this cedar. It is frequently mentioned in the bible as a symbol of power and longevity.
The Cedar of Lebanon was introduced into this country by Dr. Edward Pocock, Chaplain to the Turkey Company at Aleppo, who visited Syria frequently up to 1639. It is probable that he gave cones to his brother, Chaplain to the Earl of Pembroke at Wilton. Two trees, planted at Wilton, cut down in 1874, had 236 rings, suggesting a planting date c.1638. Dr. Pocock who later became Rector at Childrey, Oxfordshire, planted a cedar of Lebanon in the rectory garden, which is still alive today. Of the trees planted before 1740, few survived the severe frosts of that year. But there was much subsequent planting, as at Goodwood, where the Duke of Richmond planted 1,500 trees in 1761. The later plantings have survived more successfully, even the extreme weather of some winters, but have achieved only modest size, as recorded for Heaton Knolls, Shropshire, where one tree measured 355cm girth and 43m height (Mitchell) 1990, and BrightwellPark, Watlington, Oxfordshire,.335cm girth, 2008.
A proposed short expedition to the area by Joseph Dalton Hooker and Daniel Hanbury in 1860, when the area was as war torn as it is today, led a concerned Charles Darwin to write to Hooker, ‘For God’s sake do not go and get your throat cut. Bless my soul I think you must be a little insane’. They found, what they believed was the only remaining group of Cedars of Lebanon on Mount Lebanon, about 400 trees, all growing on moraines, affording perfect drainage. Based on a ring count of a felled tree, their estimated age was 350-400 years, questioning the legend of an origin in King Solomon’s time.
Subsequent interest in the Cedar of Lebanon is exemplified by a copy of a wood engraving by Edouard Riou of ‘Cedars of Lebanon at Home’ published in The Garden, Feb 26th 1876 portraying trees as Hooker and Hanbury must have seen them.
Cedars of Lebanon at Home (left)
This species is a hardy and important forest tree of the Atlas mountains of North Africa, Morocco and Algeria., at 1200-3000m above sea level, with a total area of occupation estimated between 1,300-1,500km2 at seven main locations. Genetic analysis has indicated two major sub-populations.
It was ‘discovered’ and first described by an Italian gardener, Guiseppe Manetti. Atlas cedars were introduced into this country by the 3rd Earl Somers, the date uncertain but would seem to be in the 4th decade of C19. A putative date of 1841, is compatible with letters from the 3rd Earl’s sisters, Oct./Nov. 1847, assuring him that his ‘cedars grow wonderfully’ (Emily) and ‘the garden is celebrated for possessing those Algerian shrubs you sent over’ (Hatty). They exist today at his home, EastnorCastle, Ledbury, Herefordshire, as very fine trees..
|Cedrus atlantica Glauca - long shoots with|
upstanding dwarf shoots.
|Cedrus atlantica Glauca - leaves on one long |
shoot and apparent rosettes on dwarf shoots.
The blue form arises spontaneously in wild populations. Most of the C19 cultivars, very popular today, were produced in France, the best known ‘Glauca’ in 1855 and the weeping form ‘Pendula’ in 1900.
Commercial hybridisation is extensive.
This is an Himalayan species, with an eastern limit of distribution, Western Nepal – Eastern Afghanistan, 1200-3000m above sea level.
The Deodar, possibly arrived in this country in 1822, but a more reliable date is 1831 when it was introduced by the Hon. Leslie Melville into estates in Scotland. In 1841 the Hon. T.F.Kennedy, then head of Woods and Forests, procured seeds in large quantity, from the Himalayas. In the spring of 1846 and the following autumn, some 10,000 seedlings were distributed. On the whole these early trees did not do well, many dying off suddenly at about 30-40 years. A fungal infection is suspected. Since then the Deodar, became frequently and more successfully planted in Victorian times on estates and large gardens, even as an avenue, as at Poltimore, Exeter, where trees planted 1851-52 were still vigorous by 1906 having reached heights of 23-27m. However, the frequency of the Deodar has been affected by urbanisation, remnants today occurring around towns and in urban parks and small gardens.
|Cedrus deodara - tip of pendant shoot.||Cedrus deodara Aurea - Golden Deodar in parkland.|
This species was ‘discovered’ by the Victorian explorer, Sir Samuel Baker, who was informed by the monks of Trooditissa of a species of ‘pine’ which grew only in a small inaccessible region without paths on the mountain between the monastery of Kyker and the town of Khrysokus. Baker sent a man to locate the tree and bring back specimens; he reported the trees grew in a secluded area, and were scarce. On September 24th 1879 Baker wrote to Joseph Dalton Hooker about the discovery of a form of Cedar of Lebanon; shortly afterwards Hooker received a specimen with short leaves and small female cones for which Hooker suggested the name Cedrus libani var. brevifolia, trivial name, Cyprus Cedar. Plants were raised from seed at Kew in 1881. No other species of cedar grows on Cyprus.
Its restricted distribution to one location has since been confirmed, less than 20km2 in the Triplos area of the Paphos State Forest in the Troodos Mountains of Western Cyprus. The population is stable, although some trees show signs of dieback. There are five natural stands between which there appears to be some genetic variation.
In the modern world where anthropogenic factors bear heavily on natural vegetation, there is a watching brief by the International Union for Conservation of Nature and National Resources, IUCN, guide to status of species as components of world vegetation, in the form of a Red List of Threatened Species. The List categories range through, not evaluated/data deficient/least concern/ near threatened/vulnerable/endangered/critically endangered/extinct in the wild/extinct.
Conservation is significant in preserving the genetic diversity of any species
Cedar of Lebanon
Cedar of Lebanon is recorded as a ‘vulnerable’ level threat in the IUCN Red List. It is probable the risk status was recognised as early as C11 and was the motive for the Phoenician invasion of Cyprus, to conserve these trees, the mountains of Cyprus offering an alternative source.
|Cedrus libani in St John's Churchyard, |
|Cedrus libani - shoot with cones.|| |
Many centuries of deforestation in Lebanon have resulted in a minute fraction of trees remaining today. While the tree is protected by law, such guarantee of preservation is limited by sectarian views and politics. Of the twelve remaining cedar stands in Lebanon, one of the largest, Tannourine, has become infested by a wood wasp, the cedar spinning saw fly, Cephalcia tannourinensis. The sawfly lays eggs in cedar buds in late April-May. Larvae emerge when buds open, feed on the leaves, and after the last moult drop to the ground to hibernate. First discovered in 1998, severe infestation put adjacent forests at risk, including the UNESCO World Heritage Site, the Forest of the Cedars of God. It is suspected that recent changes in climate might have been responsible for the infestation, warmer weather and drought causing a change in life cycle of the sawfly, from one to three in a year. In recent years a lack of snow may be significant. The Cedar of Lebanon requires a combination of low temperature, snow and frost, rain and summer mists, for seed dissemination and germination. Recent melting of snow on mountains could cause elevation of trees to higher levels
A pest control programme since 1999 of annual spraying has so far prevented spread, and control by biological methods appears possible in future based on the naturally occurring fungus Beauveria bassiana Clade C.
A consequence of the fashion for planting Cedar of Lebanon in England, over three centuries, is its presence today in parks and gardens of older properties. In response to the vulnerability of now old trees, planted in C18 and C19, in 1995 the National Trust established a Plant Conservation Programme at Knightshayes, with a survey of N.T. properties in England, Wales and Northern Ireland, to locate those trees which predated C20, from which the best clones could be propagated.
The identity of trees planted later is suspect, being raised from seed of hybrid origin.
Raising plants of this cedar by cuttings has always been difficult, but now greater success is achieved, with experience of selecting the right sort of vegetative material at the right time of year, using the side veneer graft method, at the new one hectare National Trust Plant Conservation Centre at an undisclosed location in East Devon.
Decline of Atlas cedars over the last 50 years warrant a status assessment of ‘endangered’.
Atlas Cedar has an estimated forest loss in Morocco of 75% between 1940-1982 and 25% between 1984-2003. Partial loss is the result of uncontrolled logging and overgrazing. Many stands are located in National Parks and so are protected, but recent droughts have had a significant effect likely to continue if the region becomes more arid.
It is predicted that pests and diseases will increase with rising temperatures, affecting leaf cover and bark integrity. Crown defoliation is effected by processionary caterpillars. Bark is damaged by the cedar bark beetle, Phloeosinus cedrii and stripped by the Barbary Macaque, with incidental effect of loss of its own habitat. The Macaque is additionally affected by illegal poaching of juveniles.
Deodar: status is often referred to as ‘least concern’ although it has not been truly evaluated. While logging occurs, there is regeneration. There are still many extensive forests left, in addition to protected areas.
Cyprus cedar occupies an area less than 20km2, such a small area putting the trees at risk. If there is further decrease in rainfall, its status could be upgraded to ‘critically endangered’. All five stands are designated nature reserves. Human activities and grazing by animals is prohibited. The major threat is of fire; there is an effective fire prevention system.
The degree to which cedars are related presents a taxonomic problem.
Joseph Dalton Hooker’s extensive travels to the Himalayas and Nepal, Palestine and Morocco in the second half of C19 led to his belief that cedars in those regions were extreme forms of an original cedar, now extinct. He believed the three well marked forms are usually distinct, but grade into one another, and from each form varieties would arise.
From a pragmatic view they are given specific status, with the option of recognising differences at the subspecies level, as in the Cedar of Lebanon, where there are possibly two main types, the main form, C.libani subsp. libani, and a slightly different form which grows in South West Turkey, C. libani subsp. stenocoma, or at varietal level, C. brevifolia could be named C.libani var. brevifolia.
Beyond consideration of morphological characters, karyotype analysis would seem to be the route to be followed in the quest for species diagnosis. The basic haploid number in the Pinaceae is 12, except for Pseudotsuga where it is 13. Cedar studies of 11 populations of the four species, have shown chromosomes similar in size and form, metacentric, two arms roughly equal in length, the centromere median in position. However, the application of fluorescent dyes, fluorochromes, which re-emit light on excitation, indicate specific banding patterns in each of the species. In C. deodara, eight GC rich chromomycin A3 bands appear, in C. libani and C. brevifolia, six, and C. atlantica, four. Such techniques should aid us in our future understanding of the relationship between these species.
CULTURAL SIGNIFICANCE AND ECONOMIC USES
True cedars have strong cultural links with the Near East. In particular Arabs of all sects attribute intelligence and eternal life to the Cedar of Lebanon. It is frequently mentioned in the Bible as a symbol of power and longevity. It is used as a national symbol today in a variety of circumstances.
In the UK true cedars are valued ornamental elements in parks and gardens, but age can bring problems, particularly the Cedar of Lebanon. Branches grow out from the trunk almost horizontally allowing water to be trapped in the axil of trunk and branch, leading to wood rot. Branches can fall without warning. Local Authorities then may elect to fell a tree on safety grounds when it reaches an age of about 150 years.
Economic uses are based on timber strength and durability.
Throughout the ages, from the Phoenicians onwards, C.libani has been used to construct buildings and ships.
In Morocco and Algeria, C. atlantica is the principal timber tree; leaves are used for tanning.
There may be a future use for oil in the medical and pharmaceutical industries.
In India, C. deodara has one of the strongest timbers, equally important as teak; it is easy to saw, used primarily for building, furniture and poles upholding power lines, but unsuited for wider use as oil oozes out when exposed to direct sunlight discolouring any coating. An additional use is for drawing equipment.
C. deodara oil has been demonstrated to possess insecticidal and fungicidal properties, and a potential for control over deterioration of materials during storage. The commercial possibilities have not, so far, been explored. Oil production started in the late 1950s but not produced commercially until very recently. These trees contain a range of compounds in different organs and tissues, which may have pharmaceutical interest. The bark contains a large amount of the flavonal, taxifolin, which suppresses UV induced skin cancer, inhibits ovarian cancer and enhances efficency of some antibiotics.
Today, the widely used commercial cedarwood oil is not produced from Cedrus. It is steam distilled from wood of members of the family Cupressaceae.
Oil of Cedarwood Texus, from Juniperus mexicana Schiede
Oil of Cedarwood Virginian, from Juniperus virginiana L.
Oil of Cedarwood Chinese type, from Cupressus funebris Endlicher
Cedarleaf oil from Thuja occidentalis L.