Previous pageTable of ContentsNext Page

Chapter 10

CEDARWOOD OILS

DESCRIPTION AND USES

Although termed cedarwood oils, the most important oils of this group are produced from distilling wood of a number of different junipers/cypresses (Juniperus and Cupressus spp.), rather than true cedars (Cedrus spp.). A cedar leaf oil is distilled from Thuja occidentalis but is not discussed here.

Cedarwood oils each have characteristic woody odours which may change somewhat in the course of drying out. The crude oils are often yellowish or even darker in colour and some, such as Texas cedarwood oil, are quite viscous and deposit crystals on standing. They find use (sometimes after rectification) in a range of fragrance applications such as soap perfumes, household sprays, floor polishes and insecticides. Small quantities are used in microscope work as a clearing oil.

All the cedarwood oils of commerce contain a group of chemically related compounds, the relative proportions of these depending on the plant species from which the oil is obtained. These compounds include cedrol and cedrene, and while they contribute something to the odour of the whole oil they are also valuable to the chemical industry for conversion to other derivatives with fragrance applications. The oils are therefore used both directly and as sources of chemical isolates.

In India, Cedrus deodara oil has been shown to possess insecticidal and antifungal properties and to have some potential for control of fungal deterioration of spices during storage. However, its commercial use for this purpose remains, at present, speculation.

WORLD SUPPLY AND DEMAND TRENDS

Markets

Excluding the People's Republic of China, for which the magnitude of consumption of domestically produced cedarwood oil is not known, the United States, Western Europe and Japan are the major markets for the oil. (After processing, the derivatives that are produced and their formulated products have a more diverse range of markets.)

The USA utilizes much of its own Texas and Virginia cedarwood oils but also imports significant quantities of Chinese oil. Imports for the period 1989-93, and their sources, are shown in Table 19. Levels of imports over the five years averaged just under 400 tonnes annually, with a range of 320-460 tonnes but no clear trend.

Japanese imports for the same period are shown in Table 20. They averaged about 170 tonnes pa, most of which was from the USA. This suggests that imports are intended mainly for derivative manufacture - Chinese oil has a lower cedrol content than American oil and is used more in its own right as a fragrance oil than as a source of chemical isolates.

In Europe, demand for oil is mainly of the Chinese type. Essential oil dealers indicate that demand is good and should remain so providing supplies continue to be adequate from this source.

Supply sources

Production data are not available for either of the main producers, the People's Republic of China and the United States, and export statistics are also incomplete (US exports of cedarwood oil, for example, are not recorded separately but included with clove and nutmeg oils). It is not possible, therefore, to be precise about the scale of world production or trade. However, Chinese exports are probably of the order of 400-500 tonnes pa, with American exports something over half of this.

East Africa used to be an important source of cedarwood oil but over-exploitation of the wild resource has meant that only very occasional shipments are now available.

Morocco produces cedarwood oil from trees growing in the Atlas mountains but the volumes are believed to be small.

Himalayan cedarwood oil is a relatively recent addition to the list of cedarwood oils produced commercially. Production began in India in the late 1950s and was estimated twenty years later to be around 25 tonnes pa. Most of the oil is consumed domestically. In the seven years 1986/87-1992/93, average recorded exports amounted to less than one tonne pa.

Quality and prices

While overall olfactory properties are important and will be judged by prospective buyers, the use of cedarwood oils as raw materials for derivative manufacture means that chemical composition is also important.

International (ISO) standards exist for Texas and Virginia cedarwood oils. For the former, an alcohols content (expressed as cedrol) in the range 35-48 percent is specified, with a minimum cedrol content of 20 percent. For Virginia oil, a maximum cedrol content of 14 percent is stipulated. Various physico-chemical data are also defined.

In the United States, recent FMA standards replace older EOA ones and are available for Chinese as well as Texas and Virginia cedarwood oils. Compositional data for the American oils are somewhat different to those cited in the ISO standards and illustrate the fact that standards can only be treated as guidelines for facilitating the assessment of quality and not as definitive statements. The alcohols content ("cedrol and related isomers") is specified as falling in the ranges 25-42 percent and 18-38 percent for the Texas and Virginia oils, respectively. For the Chinese oil, the alcohols content is required to be 8 percent minimum.

The price of Chinese cedarwood oil has been quite stable in recent years. In the period early 1991 to early 1994 it has been available from London dealers at US$2.90-3.50/kg, the most recent price being at the lower end of this range. In comparison, Texas and Virginia cedarwood oils at the same time were approximately US$7/kg and US$13/kg, respectively.

PLANT SOURCES


Botanical/common names
Family Pinaceae
Cedrus deodara (Roxb.) Loud.
C. atlantica Manetti;
Himalayan cedarwood, deodar 
Atlas cedarwood 
Family Cupressaceae 
Cupressus funebris Endl.  Chinese cedarwood 
Juniperus virginiana L.  Virginia cedarwood, Eastern red cedar 
J. mexicana Schiede
[correct name said by ADAMS
(1987) to be J. ashei Buch.] 
Texas cedarwood 
J. procera Hochst  East African cedarwood 
Widdringtonia whytei Rendle  Mulanje cedarwood 

Cupressus funebris is commonly stated to be the source of Chinese cedarwood oil but one Chinese source indicates that Juniperus chinensis, J. formosana and J. vulgaris are also used.

Description and distribution

Cedrus deodara is a tall, evergreen tree up to 50 m high, occasionally more. It grows extensively on the slopes of the Himalayas in northern India, Pakistan and Afghanistan and is often the most important conifer at elevations of 1650-2400 m.

Cedrus atlantica occurs in the Atlas mountains of Morocco and northwestern Algeria.

Cupressus funebris is an evergreen tree or shrub with a wide distribution in Guizhou, Gansu and Sichuan provinces in the People's Republic of China.

Juniperus virginiana is a slow-growing evergreen tree, up to 18 m tall. It occurs in North America and in the USA is distributed widely from the east coast to the mid- west. Young forests are commonly formed in abandoned fields from seed spread by birds.

J. mexicana is a small tree, up to 6 m tall, and occurs in the southern United States (Texas), Mexico and parts of Central America. In the USA, like J. virginiana, it invades abandoned fields and overgrazed rangelands.

J. procera is a tall tree, up to 30 m or more. It is found in the drier highland forests of East Africa, particularly Kenya, at elevations of 1000-3000 m.

Widdringtonia whytei is a tree of rather restricted occurrence in Africa. The greatest concentration is in the Mount Mulanje area of southern Malawi.

Effects of oil production on the natural resource

Most of the cedarwood oils are obtained from wild trees but little information is published on the extent to which oil production may have affected the natural resource. In Kenya, as already noted, there has been a serious depletion of the wild trees as a result of over-exploitation for timber and oil. The position in the People's Republic of China is not known. American oil production utilizes waste wood from trees felled for timber as well as the considerable areas where the junipers grow as invasive "weeds".

HARVESTING/PRIMARY PROCESSING

For those cases where the trees are utilized for both timber and oil production sawdust, wood shavings and other waste wood materials from the saw mills are taken to the distillery for steam distillation and recovery of oil in the normal manner. Sawdust should not be exposed to direct sunlight before distillation, otherwise oil yields and quality are diminished.

In other instances, where the trees are not of a size or form that makes them suitable for primary timber utilization, such as J. mexicana, the trees themselves are cut, chipped and steam distilled. Heartwood and stumps contain the most oil although the latter are not widely utilized.

Yields and quality variation

Not unexpectedly, oil yields vary widely according to the type of cedarwood oil produced and the form in which the wood is distilled (sawdust vs chips). Heartwood is richer in oil than sapwood and commercial distillers of Texas cedarwood oil recognize higher yielding trees to be the older, slower growing ones with a strong, central axis. Yields of oil are in the range 1-5 percent.

Some chemotaxonomic studies have examined foliage oils from the various species but little systematic research has been conducted on wood oils. The variability between, and particularly within, species (for even-aged trees) is not known in any great detail. ADAMS (1987) has reported the heartwood oil yield and composition of eleven Juniperus spp. growing in the United States. The relative proportions of the important aroma constituents of the oils (alpha- and beta-cedrene, cedrol and thujopsene) varied markedly.

VALUE-ADDED PROCESSING

Rectification of the crude oil to obtain fractions with different olfactory properties, and to isolate individual constituents for derivative manufacture, is carried out either in the country of origin - where there is large-scale production and domestic consumption (e.g. China and USA) - or by end-users in importing countries (e.g. Japan and Europe).

PRODUCTS OTHER THAN OIL

Some of the species are utilized for timber purposes. Cedrus deodara is one of the most valuable Indian timbers and is used for railway sleepers and in constructional work requiring beams, posts and frames. It is also used for making pencils. The strong odour of the wood and its oily nature limits its use for indoor work.

Juniperus virginiana produces a light-weight timber which is used for some items of furniture and pencil making. In the southern United States it is sold as an ornamental tree, especially at Christmas.

J. procera is used in Kenya for pencil making, joinery, flooring, etc.

DEVELOPMENTAL POTENTIAL

For those countries which possess sufficiently large areas of Cedrus, Juniperus or Cupressus to consider sustainable oil production, then an examination and trade assessment of trial lots of oil would be worthwhile. Acceptance of oil from a new source for the international market, however, will depend on its quality (composition) and price vis-à-vis traditional cedarwood oils. If there is already some use of the wood for timber purposes then waste residues could be utilized to advantage.

Those species such as Widdringtonia whytei, which have a limited distribution, could only provide very small quantities of oil to a local market (utilizing waste sawdust from sawn wood). Economic production of such an oil could probably only be undertaken in conjunction with other oils in order to make full use of the distillation facilities.

Research needs

Areas of research that deserve attention include the following:

- Screening of indigenous Juniperus, Cupressus and Cedrus species. As noted earlier, there is little published information on the wood oil characteristics of many of these species. Leaf oil composition is often very different from wood but may contain the same types of chemical constituents and should also be examined.

- Field surveys of the resource for those species which appear to have some potential. Exploitation of wild trees is only warranted where there is a high degree of natural regeneration or where the plant is considered a weed. In these cases some form of controlled, semi-formal cultivation might be possible.

SELECTED BIBLIOGRAPHY

ADAMS, R.P. (1987) Investigation of Juniperus species of the United States for new sources of cedarwood oil. Economic Botany, 41(1), 48-54.

DIKSHIT, A. and DIXIT, S.N. (1982) Cedrus oil - a promising antifungal agent of Cedrus deodara. Indian Perfumer, 26(2/4), 216-227.

FMA (1992) Cedarwood oil, Chinese. 5 pp. FMA Monographs, Volume 1. Washington, DC: Fragrance Materials Association of the United States.

FMA (1992) Cedarwood oil, Texas. 5 pp. FMA Monographs, Volume 1. Washington, DC: Fragrance Materials Association of the United States.

FMA (1992) Cedarwood oil, Virginia. 5 pp. FMA Monographs, Volume 1. Washington, DC: Fragrance Materials Association of the United States.

GREEN, C.L., WOOD, A.B. and ROBINSON, J.M. (1988) A re-examination of Mulanje cedarwood oil (Widdringtonia whytei Rendle). Flavour and Fragrance Journal, 3(3), 105-108.

GULATI, B.C. (1982) Essential oil of deodar (Cedrus deodara). In Cultivation and Utilization of Aromatic Plants. Atal, C.K. and Kapur, B.M. (eds). 815 pp. Jammu, India: Regional Research Laboratory, CSIR.

ISO (1984) Oil of cedarwood, Virginia (Juniperus virginiana Linnaeus). International Standard ISO 4724-1984 (E). 2 pp. International Organization for Standardization.

ISO (1986) Oil of cedarwood, Texas (Juniperus mexicana Schiede). International Standard ISO 4725-1986 (E). 2 pp. International Organization for Standardization.

LAWRENCE, B.M. (1980) Cedarwood oil. Perfumer and Flavorist, 5(3), 63.

NIGAM, M.C., AHMAD, A. and MISRA, L.N. (1990) Composition of the essential oil of Cedrus deodara. Indian Perfumer, 34(4), 278-281.

ROVESTI, P. (1978) Le essenze di Juniperus procera Hochst dell'Africa orientale etiopica. Essenze Derivati Agrumari, 48(3), 282-288.

SINGH, D., RAO, S.M. and TRIPATHI, A.K. (1984) Cedarwood oil [Cedrus deodara] as a potential insecticidal agent against mosquitoes. Naturwissenschaften, 71(5), 265-266.

VON RUDLOFF, E. (1975) Chemosystematic studies of the volatile oils of Juniperus horizontalis, J. scopulorum and J. virginiana. Phytochemistry, 14(5/6), 1319-1329.

WALKER, G.T. (1968) Cedarwood oil. Perfumery and Essential Oil Record, 59, 347-350.
 
 

Table 19
Imports of cedarwood oil into the United States, and sources, 1989-93
(tonnes)
 
 
 
1989 
1990 
1991 
1992 
1993 
Total 
457 
461 
338 
317 
366 
Of which from: 
China, People's Rep. Of 
259 
342 
na 
na 
na 
Hong Kong 
158 
58 
na 
na 
na 
Canada
23 
15 
na 
na 
na 
France   
14 
na 
na 
na 

Source: US national statistics
 

Table 20
Imports of cedar oil into Japan, and sources, 1989-93
(tonnes)
 
 
1989 
1990 
1991 
1992 
1993 
Total 
159 
191 
157
195
140
Of which from: 
USA 
126 
179 
157 
193 
138 
China, People's Rep. of 
32 
12
-
1
2

Source: Japanese national statistics

 

Previous pageTop of PageNext Page