Juniperus procera is closely related to Juniperus excelsa Bieb., which is distributed in Europe and temperate Asia. The two species have sometimes been treated as conspecific, but this view is not widely accepted[].

Common Name:

General Information

Juniperus procera is an evergreen tree with a crown that is pyramidal in young trees but becoming wide-spreading and flat-topped in older ones with branches that are spreading or ascending; it usually grows up to 40 metres tall, occasionally to 50 metres. The straight, tapered bole can be branchless for up to 20 metres and up to 200cm, occasionally 300cm, in diameter; it is often heavily fluted, the outer bark fissured and exfoliating in long narrow papery strips[, ].
The tree is extensively exploited from the wild for its wood, and is also the source of an essential oil and various traditional medicines. The wood used to be exported to Europe and North America for the manufacture of pencils and penholders, while small quantities were used for wardrobe linings. The essential oil is still exported[]. The tree is now grown in plantations, both in its native range and elsewhere, including South Africa, France, the United Kingdom, the United States, India and Australia[]. It is a useful shade tree, and is frequently planted as an ornamental and to provide windbreaks[].
Although frequently logged, the plant is still common or abundant in many areas of its extensive range, though there are concerns about localized declines within its range. These declines need to be monitored since, in combination, they could amount to a more significant overall population reduction and may warrant a change to a more threatened category in the future. At present the plant is classified as 'Least Concern' in the IUCN Red List of Threatened Species(2011)[].

Known Hazards

None known

Botanical References

Range

Tropical Africa - Sudan, Djibouti, Eritrea, Ethiopia, Somalia, Uganda, Kenya, eastern DR Congo, Tanzania, Malawi, Zimbabwe; to Saudi Arabia and Yemen.

Habitat

Mountain slopes, summits, on escarpments and outcrops and in forested ravines in sand, loam or clay soils over various rock types at elevations from 1,370 - 3,000 metres[].

Properties

Conservation Status	Least Concern
Medicinal Rating
Other Uses Rating
Habit	Evergreen Tree
Height	30.00 m
Pollinators	Wind
Self-fertile	No
Cultivation Status	Cultivated, Ornamental, Wild

Cultivation Details

Juniperus procera is a tropical highland species, where it is commonly found at elevations between 1,800 - 2,800 metres, though it also occurs in the broader range of 1,000 - 3,500 metres[]. It is found in areas where the mean annual temperature ranges from 5 - 20°c. The mean annual rainfall in the forest belt where it is mainly found is 1,000 - 1,400mm, but the tree is also found in areas where the rainfall can range from 300 - 2,000mm. Individual trees can survive in hot and dry conditions, once established, but in areas with low rainfall, the trees are generally of poor form and small size. Where rainfall exceeds 1,400mm the forests dominated by Juniperus procera are gradually replaced by moister types of evergreen forest in which Juniperus procera becomes increasingly rare[].
Requires a sunny position[]. Prefers rocky soils, with a light to medium texture and free drainage[]. Found wild in sand, loam or clay soils over various rock types, including basalt, volcanic ash and cinders, granite, limestone, and metamorphic rock[].
The tree is assumed to be deep-rooting, like other Juniperus spp., but the characteristics of its root system are poorly known[].
Growth, especially of young plants, is slow. In Ethiopia 10 - 15-year-old plantation trees were 6 - 9 metres tall, with a bole diameter of 8 - 16cm, whereas 30 - 40-year-old plantation trees were 17 - 21 metres tall, with a bole diameter of 16 - 29cm. In a 200-year-old stand, the trees were 37.5 m tall, with a bole diameter of 107cm[].
In the Usambara mountains in Tanzania (at an elevation of 1,450 metres, an average annual temperature 18°c, and an average annual rainfall of 1,070mm) 61-year-old trees in a density of 182 trees/ha had an average height of 32.5 metres and an average bole diameter of 47cm. The standing volume was 247 m³ per hectare[].
A naturally regenerated 15-year-old stand in Kenya, the result of an earlier fire, had an average tree height of 14.7 metres and an average bole diameter of 23cm; 35 years later the trees in this stand (density 262 stems/ha) had an average height of 23.5 metres and an average bole diameter of 39cm[].
The growth of plantations ranges from 3.5 to 13 cubic meters per hectare per year, averaging 7.5 cubic metres, considerably less than that of some exotic species on the same sites, such as Eucalyptus globulus which produces 50 cubic metres[].
The tree has irregular flowering and fruiting periods, only flowering once every several years. It is wind pollinated and seeds are dispersed by birds[, ].
Juniperus procera is a prolific seed-bearer and the seeds, though sometimes damaged by seed-boring insects, are usually fertile[].
Young seedlings are very light demanding and absolutely intolerant of any decomposing organic matter covering the ground. Therefore the seeds can only germinate freely in open, grassed areas or among shrubs, such as in glades or forest edges, where there is adequate light and mineral soils. Consequently, Juniperus procera forests can only develop in two principal ways: either saplings are found growing under the shelter of bushes at forest edges, or natural regeneration occurs after a fire or in large clearings of other origin, giving rise to usually very dense, even-aged stands of trees with long, branch-free boles. Due to these strict requirements, artificial regeneration appears to be the easiest and fastest way to maintain Juniperus procera forests[].
The production of suitable logs for the sawn wood and veneer market may be possible with a rotation period of 70 - 100 years[].
A dioecious species, both male and female forms need to be grown if fruit and seed are required[].

Edible Uses

None known

Medicinal

The tree is often used in traditional African medicine. Some research has been carried out into the active compounds in the plant, and these have tended to support the traditional uses.
The essential oil obtained from from the leaves is rich in cedrol. It has shown antioxidant activity[].
The leaves and bark contain diterpenes with antibacterial activity[].
The butanol fraction of an ethanol extract of the bark has been shown it inhibit implantation of the foetus[].
The bark contains about 3.5% tannin[].

An infusion of the powdered young twigs is taken as a remedy against intestinal worms[]. The smoke from the twigs is inhaled as an expectorant[].
Applied externally, people with rheumatism are treated by exposure to the smoke of burnt twigs and seed cones[].

The leaves are used in the treatment of stomach aches[].
The dried, powdered leaves are applied on wounds of humans and animals. A hot bath to which the leaves are added is used in the treatment of fever[, ].

The resin is used as a stimulant and is also applied to ulcers[].

Macerations of the bark are drunk, and also applied as a vaginal wash, to act as birth-control agents[].

A decoction of the seed cones is used as a sudorific and emmenagogue[].

Agroforestry Uses:

Since the tree can grow in extreme conditions, it is replanted in deforested areas as a means of soil conservation or improvement, and also for erosion control.
A useful shade tree, it is frequently planted in windbreaks[], and also in ornamental hedges[].
Litter fallen from the tree makes the soil acidic, so Juniperus procera should not be intercropped with crops[].

Other Uses

The wood contains 0.5 - 3% essential oil, which is distilled mainly from the sawdust. It is used in the cosmetic industry in soaps and perfumes[, ]. The most important component iscedrol (23 - 79%), which is known to have antitermite effects[].

The wood is used for making fire sticks[].

Older trees are usually hollow and can be used in making beehives[].

The heartwood is pale red, yellow-brown or purple-red when freshly cut, turning reddish brown on exposure; it is clearly demarcated from the up to 25mm wide band of cream-coloured or white sapwood. The grain is usually straight; the texture fine and even. The wood is liable to bleach in the sun and is sometimes streaked with zones of darker and lighter colour which produce an attractive figure. In-grown bark, spiral grain and compression wood are common defects. The wood is medium-weight; very durable, even in contact with the soil, it is resistant to fungi, termites and most borers except Oemida gahani. The sapwood is not susceptible to attack by Lyctus beetles. It seasons well when dried with care, but larger pieces are liable to end-splitting and surface-checking, and the wood should not be allowed to dry rapidly in the initial stages[]. It is easy to work with hand and machine tools, although it is rather brittle and fissile, tending to break and chip on drilling and mortising; it can split on nailing and screwing, and pre-boring is necessary; it glues, stains and polishes well[, ].
The wood is very fragrant, with a characteristic and persistent aromatic cedar smell. It is widely used for building (both construction and lining), joinery, flooring (strip and parquet), furniture and all sorts of outdoor work such as roofing shingles, fence posts, water flumes and transmission poles. Ii is used traditionally for making fire sticks, beehives and salt-troughs. It is also suitable for ship and boat building, agricultural implements, musical instruments, carving, vats, toys and novelties, turnery, draining boards and food containers. It can be used for making veneer and plywood, hardboard and particle board, and as pulpwood[, ].
The wood is used as firewood and to make charcoal[]. It burns evenly, but fast when fresh, and the charcoal does not last long[].

Propagation

Seed - germination is best at around 20°c and is better in full sun than in the shade. The germination rate in nursery seed beds is usually 40% after 6 weeks, but considerable variation has been found in the seed and germination characteristics. The seed may benefit from scarification before sowing in order to speed up and improve germination. This can usually be done by pouring a small amount of nearly boiling water on the seeds (being careful not to cook them!) and then soaking them for 12 - 24 hours in warm water. By this time they should have imbibed moisture and swollen - if they have not, then carefully make a nick in the seedcoat (being careful not to damage the embryo) and soak for a further 12 hours before sowing. Alternative methods of scarification include pre-treatment with concentrated sulphuric acid or scorching the seeds. Seedlings are ready to be planted out when 1 - 2 years old and 15 - 25cm tall[].
Wildlings are also used for planting[].
Under conditions in which Juniperus procera readily regenerates, stand establishment by direct sowing may even be applicable[].
Juniperus procera is easily propagated by seed. The seed stores well, for at least 12 months[, ].
Vegetative propagation is possible: stecklings (rooted cuttings) with well-developed root systems easily establish and grow well[]. In experiments, rooting was best in cuttings from young plants (5 months old), but somewhat older plants (10 - 15 months) yield more cuttings. Rooting in cuttings from mature trees is poor[].

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