Cinnamomum (PROSEA Spices)

Plant Resources of South-East Asia
Introduction

Cinnamomum burmanni - 1, flowering branch; 2, flower; 3, stamen of 1st and 2nd whorl; 4, stamen of 3rd whorl with glands; 5, staminode of 4th whorl; 6, fruits

Cinnamomum Schaeffer

Protologue: Bot. exped.: 268, 269 (1760).

Family: Lauraceae

Chromosome number: x = 12; 2n = 24 (C. burmanni, C. cassia, C. loureirii)

Major species and synonyms

Cinnamomum burmanni (C. Nees & T. Nees) C. Nees ex Blume, Bijdr. Fl. Ned. Indië 11: 569 (1826), synonyms: Laurus burmanni C. Nees & T. Nees (1823), Cinnamomum mindanaense Elmer (1910).

Cinnamomum cassia J.S. Presl, Prir. rostlin 2: 36, 44-45, t. 6 (1825), synonyms: Laurus cassia L. (1753), Cinnamomum aromaticum C. Nees (1831).

Cinnamomum loureirii C. Nees, Syst. laur.: 65 (1836), synonyms: C. obtusifolium (Roxb.) C. Nees var. loureiri C. Nees ex Watt (1889).

Cinnamomum verum J.S. Presl - see separate article.

Other Cinnamomum species - see chapter on Minor spices.

Vernacular names

General

Cassia (En).
Cassia, cinnamon (Am). Cannellier (Fr)
Indonesia: kayu manis
Malaysia: kayu manis
Philippines: cinnamon, kanela
Vietnam: quế, long não, re

C. burmanni

Indonesian cassia, Padang cassia, cassia vera (En)
Indonesia: kayu manis (Indonesian), ki amis (Sundanese), manis jangan (Javanese)
Philippines: kaliñgag (Manobo), kami (Bagobo)
Thailand: suramarit (Nakhon Ratchasima)
Vietnam: quế trèn, quế rành

C. cassia

Chinese cassia, Chinese cinnamon, cassia lignea (En)
Cannellier de Chine, cannellier casse (Fr)
Indonesia: kayu manis cina (Indonesian)
Laos: s'a: chwang
Thailand: kaeng (Chiang Mai)
Vietnam: quế thanh, quế dơn, quế quảng

C. loureirii

Vietnamese cassia, Saigon cassia, Saigon cinnamon (En)
Laos: kh'e:
Thailand: opchoei (Bangkok)
Vietnam: quế thanh hoá, quế quì

Origin and geographic distribution

Cinnamomum comprises 150-250 species occurring in continental Asia, Malesia, Australia, the Pacific, and a few species in Central and South America. Within the Malesian area some 90 species have been recognized.

Cassia and cinnamon are among the oldest of spices, reportedly reaching ancient Egypt by the 17th Century B.C., but it seems likely that the barks entering the cinnamon trade over the course of time have been of different botanical origin. It seems probable that the Greek and Romans had both cinnamon and cassia, but the Arab traders shrouded the sources in mystery. Cinnamon and cassia were among the first spices sought after by most 15th and 16th Century European explorers.

C. burmanni is distributed in Malesia. It is cultivated in Indonesia (Java, Sumatra) and the Philippines.

C. cassia occurs in South China, Burma (Myanmar), Laos and Vietnam. It has been introduced into Indonesia, Sri Lanka, South America, the southern United States, and Hawaii. It is only commercially cultivated in China and Vietnam.

C. loureirii occurs naturally in the mountains of Annam (Vietnam). In Vietnam it has also been taken into cultivation.

Uses

Although Ceylon cinnamon (C. verum) is more widely used at the household level, the dried inner bark of the 3 types of cassia is similarly used for flavouring foods, domestically and industrially. The derived bark oil (prepared by distillation) or oleoresin (prepared by solvent extraction) are used to a much lesser extent. The preferred cassia type differs from country to country. Cassia bark oils are also used in soaps and perfumes. Chinese cassia is the source of (Chinese) cassia leaf oil (usually referred to as cassia oil), obtained by distilling twigs and leaves. It is used for similar purposes as cinnamon and cassia bark oils in perfumery and flavouring, but it is of special importance in cola-type drinks.

In the United States the regulatory status "generally recognized as safe" has been accorded to Chinese cassia (GRAS 2289), its bark oil (GRAS 2258/2290) and its leaf oil (GRAS 2292). The same holds for Vietnamese cassia (GRAS 2289), its bark oil (GRAS 2290) and its leaf oil (GRAS 2292).

The dried immature fruits of C. cassia are known as cassia buds or "bunga lawang" and are used as flavouring. They have a cinnamon-like odour and sweet pungent flavour, and are extensively used in sweet pickles. In traditional customs, a pair of cassia buds are part of a potion to be drunk by bride and groom.

Powdered cassia bark is listed in the British Herbal Pharmacopoeia as a specific remedy for flatulent dyspepsia or colic with nausea. The barks of all 3 species are well-known folk medicines for a long list of ailments such as diarrhoea, gripe, malaria, coughs and chest complaints. In European phytomedicine, cassia oil (0.05-0.2 g daily intake) is used in teas and other galenicals for its antibacterial, carminative, and fungistatic properties, and also for loss of appetite and dyspeptic disturbances.

Cinnamomum timber or camphorwood is a lightweight to medium-weight hardwood used for decorative work, furniture, and is suitable for plywood manufacture. The heavier timber is used for construction under cover. The fragrant wood is very suitable for making moth-proof chests. Cinnamomum trees (in Indonesia C. burmanni in particular) are frequently planted as wayside and shade trees.

Production and international trade

C. burmanni. Only the bark is economically important. Padang (West Sumatra) is an important production area. The harvested area in Indonesia in 1998 was estimated by FAO at 60 000 ha, with a production of 40 000 t. Indonesian cassia is an important export product from Indonesia: during the years 1991-1994 the United States imported annually about 13 000 t quills from Indonesia, valued at about US$ 23 million.

C. cassia. Only the bark and the leaf oil are economically important. China (Kwangsi and Kwangtung Provinces) is the main producer and exporter of Chinese cassia. The harvested area in 1998 was estimated by FAO at 35 000 ha, with a production of 28 000 t. Exports of dry bark from China during the period 1966-1976 amounted to 1250-2500 t annually. In 1987-1993 the United States imported annually about 600 t of cassia bark and 340 t of cassia leaf oil. Given the considerable domestic consumption in China, the production of leaf oil must be in excess of 500 t. In 1991-1994 cassia leaf oil fetched a price of about US$ 30-35/kg.

C. loureirii. Only the bark is economically important. Vietnam is the main producer of Vietnamese cassia. The harvested area in 1998 was estimated by FAO at 6100 ha with a total production of 3400 t. Exports of dry bark from Vietnam during the period 1966-1976 varied from 5-300 t.

Cassia bark oils and oleoresins are produced in the importing countries in small quantities. Leaf oil is mainly distilled in the producing countries.

Cinnamomum timber is traded in Malaysia in the trade group "medang” together with other Lauraceae genera.

Properties

All Cinnamomum are aromatic, the aromas depending on different substances and mixtures of them. Some are characterized by cinnamaldehyde, others by eugenol, safrole or camphor.

The dried inner bark of the 4 main species is very similar in composition. It contains a steam-volatile oil, fixed oil, tannin, resin, proteins, cellulose, pentosans, mucilage, starch, calcium oxalate and minerals. The characteristic odour and flavour properties are mainly determined by the constituents of the steam-volatile aromatic oils. Of the non-steam and less volatile constituents, only coumarin contributes substantially to the organoleptic properties.

C. burmanni. The essential-oil content of the bark is 1-4%. The bark oil is a colourless to brownish-yellow liquid, mainly consisting of cinnamaldehyde, and lacking eugenol. The leaf oil also mainly consists of cinnamaldehyde, but the main constituent of the root bark oil is camphor.

C. cassia. Bark oil and leaf oil of Chinese cassia have similar compositions. The essential-oil content of the bark is 1-4%. The bark oil consists of 70-95% cinnamaldehyde, with only traces of eugenol. The essential-oil yield from leaves and twigs is 0.3-0.8%. The leaf oil is a dark brown liquid, consisting of 70-95% (ISO: > 80%) cinnamaldehyde, with only traces of eugenol. Cassia buds contain 1.9% essential oil (about 80% aldehydes). A monograph on the physiological properties of Chinese cassia bark oil has been published by the Research Institute for Fragrance Materials (RIFM).

The 1000-seed weight is 370-400 g.

C. loureirii. The essential-oil content of the bark is 1-7%. The bark oil is a yellow-brown liquid, consisting mainly of cinnamaldehyde, with only traces of eugenol. The leaf oil is a pale brown liquid; the composition seems to be rather different from the bark oil. The root oil is a pale brown oil, mainly consisting of cinnamaldehyde.

Composition

Cinnamomum burmanni: Indonesian cassia bark oil (from China) (Source: Ji Xiao-duo et al., 1991)

51.4% 1,8-cineole
12.5% α-terpineol
9.0% camphor
8.5% terpinen-4-ol
1.8% borneol
1.6% α-pinene
1.6% β-caryophyllene
1.0% para-cymene
0.5% β-eudesmol
0.5% camphene
0.4% elemol
0.4% myristicin
0.4% β-pinene
0.3% α-humulene
0.1% bornyl acetate
89.7% total

Cinnamomum burmanni: Indonesian cassia leaf oil (from China) (Source: Ji Xiao-duo et al., 1991)

28.5% 1,8-cineole
16.5% borneol
6.4% α-terpineol
6.1% para-cymene
5.8% spathulenol
4.1% terpinen-4-ol
3.1% bornyl acetate
2.9% β-caryophyllene
1.9% α-pinene
1.7% β-pinene
1.5% cinnamyl acetate
1.2% myristicin
0.6% elemol
0.4% α-humulene
0.4% linalool
0.2% camphene
0.1% β-eudesmol
81.4% total

Cinnamomum cassia: Chinese cassia leaf oil (from China) (Source: Zhu et al., 1993)

74.1% cinnamic aldehyde
10.5% 2-methoxycinnamaldehyde
6.6% cinnamyl acetate
1.2% coumarin
1.1% benzaldehyde
0.7% 2-phenylethyl acetate
0.6% 2-phenylethanol
0.6% 2-methoxybenzaldehyde
0.2% 2-methylbenzofuran
0.2% 3-phenylpropanal
0.2% salicylaldehyde
0.2% cinnamyl alcohol
0.2% nerolidol (unknown isomer)
0.1% acetophenone
0.1% α-pinene
96.5% total

Cinnamomum cassia: Chinese cassia leaf oil (from Australia) (Source: Senanayake, 1977)

77.2% cinnamic aldehyde
15.3% coumarin
3.6% cinnamyl acetate
1.2% benzaldehyde
0.8% 4-ethylguaiacol
0.4% ethyl cinnamate
0.2% 2-phenylethyl acetate
0.2% 2-phenylethanol
0.1% α-terpineol
0.1% eugenyl acetate
0.1% benzyl benzoate
0.1% terpinen-4-ol
0.1% nonanal
trace 1-hexanol
trace chavicol
trace camphene
trace 1,8-cineole
trace cinnamyl alcohol
trace cuminaldehyde
trace eugenol
trace farnesol (unknown isomer)
trace geranial
trace guaiacol
trace α-humulene
trace isoeugenol
trace linalool
trace methyl benzoate
trace 3-phenylpropanal
trace α-pinene
trace β-pinene
trace terpinolene
trace 2-vinylphenol
99.4% total

Cinnamomum cassia: Chinese cassia bark oil (from China) (Source: Vernin et al., 1990)

65.5% (E)-cinnamic aldehyde
8.7% coumarin
3.6% cinnamyl acetate
2.7% 2-methoxycinnamaldehyde
0.9% benzaldehyde
0.7% 2-methoxybenzaldehyde
0.6% benzyl benzoate
0.2% cinnamyl alcohol
0.2% 2-phenylethyl acetate
0.2% eugenyl acetate
0.1% (Z)-cinnamic aldehyde
0.1% 2-phenylethyl benzoate
0.1% 3-phenylpropanal
trace caryophyllene oxide
trace α-pinene
trace camphene
trace β-pinene
trace myrcene
trace α-phellandrene
trace δ-3-carene
trace α-terpinene
trace para-cymene
trace limonene
trace β-phellandrene
trace (Z)-β-ocimene
trace (E)-β-ocimene
trace γ-terpinene
trace terpinolene
trace linalool
trace borneol
trace terpinen-4-ol
trace α-terpineol
trace nerol
trace geraniol
trace linalyl acetate
trace bornyl acetate
trace β-caryophyllene
trace α-humulene
trace α-muurolene
trace δ-cadinene
trace α-copaene
trace p-cymen-8-ol
trace isoamyl isovalerate
trace spathulenol
trace eugenol
trace carvacrol
trace β-elemene
trace methyl eugenol
trace benzoic acid
trace isocaryophyllene
trace γ-muurolene
trace aromadendrene
trace anisaldehyde
trace α-cadinol
trace guaiacol
trace ar-curcumene
trace (E)-β-farnesene
trace safrole
trace acetic acid
trace vanillin
trace chavicol
trace 10-epi-α-cadinol
trace methyl cinnamate
trace calamenene
trace benzyl alcohol
trace trans-linalool oxide (5) (furanoid)
trace cis-linalool oxide (5) (furanoid)
trace α,p-dimethylstyrene
trace ethyl cinnamate
trace 2-phenylethanol
trace salicylaldehyde
trace acetophenone
trace carvotanacetone
trace palustrol
trace α-elemene
trace styrene
trace menthene
trace butyl 2-methylbutyrate
trace (Z)-isoeugenol
trace α-himachalene
trace 3-phenylpropyl acetate
trace isoamyl benzoate
trace 2-phenylethyl formate
trace 2-vinylbenzaldehyde
trace 4-vinylbenzaldehyde
trace p-tolyl propyl ether
trace 4-tolylacetaldehyde
trace (E)-2-methoxycinnamaldehyde
trace dimethoxycinnamaldehyde
trace dimethoxy allyl phenol
trace 3-phenylpropanoic acid
trace o-methoxycinnamic alcohol
trace (E)-cinnamic acid
84.4% total

Cinnamomum cassia: Chinese cassia bark oil (from Australia) (Source: Senanayake, 1977)

87.0% cinnamic aldehyde
4.7% benzaldehyde
2.5% 2-phenylethanol
2.0% 3-phenylpropanal
0.7% 1,8-cineole
0.5% 4-ethylguaiacol
0.5% guaiacol
0.4% ethyl cinnamate
0.4% cuminaldehyde
0.3% chavicol
0.3% coumarin
0.1% benzyl benzoate
0.1% linalool
0.1% cinnamyl acetate
0.1% nonanal
0.1% eugenol
0.1% α-pinene
trace eugenyl acetate
trace terpinen-4-ol
trace camphene
trace cinnamyl alcohol
trace farnesol (unknown isomer)
trace fenchone
trace geranial
trace geraniol
trace 1-hexanol
trace 3-hexenol-1
trace α-humulene
trace isoeugenol
trace methyl benzoate
trace methyl cinnamate
trace 2-phenylethyl acetate
trace β-pinene
trace sabinene
trace safrole
trace β-selinene
trace α-terpinene
trace α-terpineol
trace terpinolene
100.0% total

Cinnamomum loureirii: Vietnamese cassia bark oil (Source: Lawrence, 1995)

92.5% (E)-cinnamic aldehyde
0.8% 3-phenylpropanal
0.6% (Z)-cinnamic aldehyde
0.6% coumarin
0.3% benzaldehyde
0.3% eugenol
0.1% β-caryophyllene
0.1% benzyl benzoate
0.1% camphor
0.1% 1,8-cineole
0.1% linalool
0.1% β-phellandrene
0.1% salicylaldehyde
0.1% α-terpineol
95.6% total

Adulterations and substitutes

In early times, cassia was usually described as a somewhat inferior substitute for true cinnamon, but it now has its own market with, for instance, the United States having a clear preference for cassia over cinnamon, and for Vietnamese cassia in particular. Nevertheless, cinnamon and cassia barks are interchangeable in many applications, and the same applies to cinnamon bark oil, cassia bark oils and (Chinese) cassia leaf oil.

Where cinnamaldehyde is the main constituent, adulteration with synthetic cinnamaldehyde is simple, and is mainly a function of the price of the natural product. Detection methods have much improved and therefore adulteration has become less common.

Methods of distinguishing cinnamon bark oil from cassia oils are based on the presence/absence of minor components such as ortho-methoxy cinnamaldehyde, eugenol and coumarin.

Description

Evergreen or deciduous aromatic shrubs or trees up to 50 m tall; bole usually branchless for up to 30 m, up to 125 cm in diameter, buttresses short or absent; bark surface smooth, rarely fissured, lenticellate, grey-brown to reddish-brown, inner bark granular, pale brown to pink or reddish-brown, with a strong aromatic smell; sapwood whitish to pale yellow.
Leaves usually opposite, subopposite, alternate or arranged spirally, simple and entire, with glandular dots and aromatic when crushed, 3-veined, rarely pinnately veined; stipules absent.
Inflorescence consisting of axillary or terminal cymose panicles of clusters or umbellules of flowers.
Flowers bisexual, rarely unisexual (and then polygamous), trimerous; tepals 6, subequal, united into a tube at base, usually hairy; fertile stamens 9, rarely 6, in 3 whorls, stamens in the outer 2 whorls introrse, in the inner whorl extrorse and with a pair of stalked or sessile glands, anthers 4-celled, rarely 2-celled; a fourth (innermost) whorl consists of 3 staminodes with slender filaments and empty anthers; ovary superior, sessile, 1-celled, with a single, pendulous, anatropous ovule, style slender, with a discoid or obscurely 3-lobed stigma.
Fruit a 1-seeded berry, globose or ovoid to cylindrical, the basal part surrounded by the enlarged and indurated perianth tube often carrying persistent perianth lobes; pedicel usually not enlarged.
Seed without albumen, with a thin testa; cotyledons large, flat, convex and pressed against each other; embryo minute.

C. burmanni. Evergreen shrub or small tree, up to 15 m tall. Leaves subopposite; petiole 0.5-1 cm long; blade oblong-elliptical to lanceolate, 4-14 cm × 1.5-6 cm, pale red and finely hairy when young, when older glabrous and glossy green above, glaucous pruinose below. Inflorescence a short axillary raceme; pedicel 4-12 mm long; perianth 4-5 mm long, after anthesis the lobes tearing off transversely about halfway; stamens about 4 mm long, staminodes 2 mm. Berry ovoid, about 1 cm long.

C. cassia. Evergreen tree up to 18 m tall, strongly aromatic in all its parts; bole up to 70 cm in diameter; bark thick, smooth in young trees, rough in mature trees, grey; twigs brown-hairy. Leaves alternate to nearly opposite; blade oblong-elliptical, 8-20 cm × 4-7.5 cm, dark shiny green. Inflorescence 7.5-18 cm long; pedicel 2-3 mm long; flowers small, about 3 mm long, pubescent, white or whitish yellow; perianth lobes after anthesis tearing off transversely at base. Fruit ovoid to ellipsoidal, 1-1.5 cm long, black to blackish-purple. Seed ovoid, 1 cm long, dark brown with paler stripes.

C. loureirii. Evergreen tree up to 8-10 m tall, similar in shape to C. cassia. Leaves opposite or alternate; petiole 12-15 mm long; blade elliptical to oblong, 7.5-12.5 cm × 3-5 cm, acuminate, rigid, green to dull green. Flowers very small, yellow-white. Fruit and seed similar to but smaller than C. cassia.

Growth and development

There is little specific information on the 3 cassia species. Cinnamomum trees generally produce moderately deep and extensive roots. Seedling growth is rapid, with formation of a well-developed taproot followed by numerous spreading laterals. There is normally a single central stem, but the true cinnamon and cassia species are relatively low-branching. Growth takes place in flushes, young leaves often being reddish in colour, later turning green. Cinnamomum is open-pollinated and various small insects (e.g. flies and beetles) are the main pollinating agents. The fruits are eaten by monkeys, squirrels, bats and birds, the latter being the main seed-dispersal agents.

Other botanical information

Many South-East Asian Cinnamomum species are used as substitutes or adulterants for the true cinnamon and the 3 main cassias of commerce. Some are minor spices (see chapter on Minor spices), others have greater economic importance as timber: Cinnamomum iners Reinw. ex Blume, C. javanicum Blume, C. mercadoi S. Vidal, C. mollissimum Hook.f., C. porrectum (Roxb.) Kosterm., C. scortechinii Gamble, C. sintoc Blume, and C. subavenium Miq.

Substitutes and adulterants of local importance in southern Asia are:

Cinnamomum bejolghota (Buch.-Ham.) Sweet (syn. C. obtusifolium (Roxb.) C. Nees), which occurs from northern India to Indo-China, southern China and the Andaman Islands.

Cinnamomum impressinervium Meissner, which occurs in the Sikkim Himalaya (India).

Cinnamomum tamala (Buch.-Ham.) T. Nees & Eberm., the Indian cassia, which is distributed in India, Bangladesh and Burma (Myanmar). In India it is cultivated for bark and leaves ("tejpat”). Tejpat leaves are extensively used as a spice in India, as well as in ayurvedic preparations.

Taxonomically, the genus Cinnamomum is still poorly known and the literature should be interpreted with great care, as the identity of given names is often obscure. C. loureirii, for example, is sometimes considered as restricted to Vietnam, sometimes as distributed also in Cambodia and Laos, sometimes as also occurring in the central and northern Himalayas, and sometimes it is also confused with C. japonicum Siebold (native to China, Korea, the Ryukyu Islands and Japan) and with C. sieboldii Meissner (native to the Ryukyu Islands and widely cultivated in Japan). A thorough revision of the entire genus is badly needed.

Ecology

Cinnamomum are mostly tropical forest trees, adapted to a wide range of climatic conditions occurring between 30°N and 30°S. They tolerate short periods of waterlogging or drought. As forest trees they are partially shade tolerant, but mature trees grow well in full sunshine. They occur on well-drained, leached hillside soils of low fertility and strong acidity (pH 4-6).

C. burmanni. Indonesian cassia occurs in Indonesia from sea-level to 2000 m altitude, but in the important production area of Padang it grows best between 500-1500 m, with an evenly distributed annual rainfall of 2000-2500 mm. Light, rich sandy loams yield the best bark.

C. cassia. The main production areas in China are characterized by mean daily temperatures of about 22°C and an annual rainfall of 1250 mm in about 135 wet days. The absolute maximum temperature is about 38°C and the absolute minimum is 0°C. It is grown in southern China at altitudes up to 300 m.

C. loureirii. The main production areas in Vietnam have an annual rainfall of 2500-3000 mm, and lateritic soils of old volcanic origin.

Propagation and planting

In the case of propagation by seed, ripe fruits should be selected from mother trees producing thick bark of good aroma. They should be bagged against birds until they are harvested. Harvested fruits are left to ferment, to facilitate removal of the pericarp by washing. Seeds are only briefly viable, and are usually planted in shaded nurseries, preferably in fine sandy soil, and watered regularly.

C. burmanni is usually grown from seed, but also from cuttings. Fresh seed germinates in 5-15 days. The nursery period is about 8-12 months. Transplanting should be done carefully, because damage to roots increases the incidence of stripe canker. Recommended field spacing is 2-4 m × 2-4 m.

C. cassia is usually grown from seed, but sometimes also from cuttings. Seedlings are raised in nursery beds and transplanted when 1-2 years old. Cuttings are taken from flushes when the leaves are horizontal and of firm texture. One, two or multiple leaf cuttings may be used. Field spacing is 1 m × 1 m. A density of 10 000 trees/ha is also considered optimal for leaf-oil production.

C. loureirii is usually raised from seed, sometimes also by cuttings, layers, or suckers. Seedlings are transplanted when about 1 m tall at the age of 1 year.

Field spacing is a compromise between high yield of thin bark (close spacing) or lower yield of thick, high-quality bark (wide spacing). The formation of a tall straight unbranched trunk should be encouraged.

In vitro production of active compounds

Callus tissue and cell suspension cultures obtained from leaves of C. cassia show production of (-)-epicatechin, procyanidin B2, procyanidin B4 and procyanidin C1. These compounds are precursors of condensed tannins, which are assumed to be the main components responsible for the plant's medicinal effects. Cinnamaldehyde was not synthesized by the cell cultures.

Husbandry

After-planting care mainly consists of weeding. Lower branches are removed by cutting off close to the trunk. Cassia plantations generally receive only organic wastes or mulches, but fertilizer recommendations would be similar to those for true cinnamon: phosphate in the planting holes, annual applications of a 2 : 1.5 : 1.5 mixture of urea, rock phosphate and potassium chloride (40-100 kg/ha, depending on the age of the trees), and a nitrogenous top dressing at the beginning of the rainy season for good tree growth and regrowth of coppiced trees. Tephrosia candida (Roxb.) DC. has reportedly been used successfully as an auxiliary crop (cover crop, green manure) in Sumatra, sown 6 months ahead of planting Indonesian cassia, and lasting for about 3 years.

Diseases and pests

Many diseases and pests of Cinnamomum verum also occur on other Cinnamomum. Diseases may include stripe canker (Phytophthora cinnamomi), pink disease (Corticium salmonicolor, syn. C. javanicum), white rot (Fomes lignosus), rust (Aecidium cinnamomi) and anthracnose (Glomerella cingulata). A serious witches' broom disease has recently been found on Chinese cassia in Vietnam. Control with the natural antibiotic berberine has been successful.

Ceylon cinnamon pests, which have also been reported on other Cinnamomum are caterpillars of the cinnamon butterfly (Chilasa clytia), leafminers (Acrocercops spp.), caterpillars of a leafwebber (Sorolopha archimedias), and mole crickets (Gryllotalpa spp.) damaging young seedlings.

Harvesting

Cassia trees are sometimes destructively harvested at the age of 10-15 years, but they coppice well and are now generally grown as a coppiced bush. This entails cutting the stems low down after an initial establishment period and harvesting the bushy regrowth at regular intervals thereafter.

C. burmanni. Harvesting is still mainly by removing entire trees through thinning, gradually reducing the tree density. A stand may be first thinned in the third year to produce some inferior bark. The first proper harvest is done 2 years later, subsequent harvesting by thinning is carried out annually for about 15 years. Harvesting takes place at the beginning of the rainy season. The bark is removed from the lower part of the trunk in strips of 1 m × 5-10 cm. Then the tree is felled and the bark is stripped from the upper part of the trunk and larger branches. The stumps are sometimes allowed to regrow into a new stand with 1-2 shoots per stump.

C. cassia. Trees are first coppiced when 5-7 years old and 1.5-2.5 m tall, the stem being 2.5-4 cm in diameter. Stems are cut a few cm above ground level and stripped of leaves and twigs, which may be used for distillation. The stumps regrow into a new stand. Subsequent harvests take place every 3-4 years, and plantation life is 40-60 years. Some trees are left uncut for the production of cassia buds or mature fruits. The cut stems are ringed at intervals of 30-60 cm (or cut into pieces), longitudinal splits are made and the bark taken off in two pieces. The bitter-tasting epidermis is removed by scraping.

An improved management system has been developed in Hawaii for Chinese cassia leaf-oil production. Trees are not coppiced to near ground level, but are cut and trained into a vertical framework or hat-rack structure to obtain maximum leaf and twig production.

C. loureirii. Harvesting is usually done when trees are 10-12 years old. Bark is removed from standing trees, sometimes with the help of a bamboo scaffolding. Horizontal cuts are made 40 cm apart, and vertical cuts 25-35 cm apart, yielding unrolled slabs. Finally, trees are felled and inferior bark harvested from smaller branches, yielding quills. Stumps are left for regrowth.

Yield

Yield data on the 3 cassia species are very scarce. For C. burmanni, average-sized trees yield about 3 kg of stem bark and 1.5 kg of branch bark. In a crop cycle of 10 years, the total yield is about 2 t/ha of bark.

Handling after harvest

Harvested bark is dried in the sun, making it curl into reddish-brown quills. Grading is mainly by type (scraped, unscraped, quills, quillings, featherings, chips), appearance (length, colour) and volatile-oil content. Sometimes the unrolled bark slabs may undergo complicated traditional methods of curing like alternate washing and drying, and some fermentation in heaps. Slabs are tied around thick bamboo for drying and for assuming a broadly curved appearance.

Grinding is usually carried out in the consuming countries. Ground cinnamon and cassias are often blended for specific purposes.

Genetic resources

Since cassia products are now derived almost entirely from cultivated sources, the pressure on the wild resource has been reduced considerably, but germplasm collections are still badly needed. About 280 accessions of cinnamon germplasm are maintained by the Indian Institute of Spices Research (IISR), Calicut, India, consisting of cultivated types and a few wild and related species. The collection has been evaluated by quality parameters.

Breeding

As propagation is mainly by seed, fruits should be collected from carefully selected mother trees, with a thick bark of good aroma.

Prospects

The demand for the spices cinnamon and cassia has always been satisfactory, and the prospects are still promising, as the competition from synthetic alternatives does not noticeably affect the trade. Consumption is likely to be mainly a function of population growth. The prospects for the essential oils seem to be less bright, as there are many alternatives. However, the market for Chinese cassia leaf oil, for instance, is still expanding, due to the soft-drink market. The increasing number of reports in the scientific literature describing the oil characteristics of Cinnamomum is evidence of the attention the genus is receiving in screening programmes for sources of commercially valuable chemical isolates. In South-East Asia, the Forest Research Institute Malaysia (FRIM) is very active in identifying species with potential for providing raw materials for local industry and farm income.

Little attention has been paid to the production of Cinnamomum wood or camphorwood, as plantation trees are merely valued for spice or essential oil. However, the wood is suitable for special decorative purposes, and there may be scope for multipurpose plantations including timber production. More research is needed on the silvicultural management of camphorwood plantations.

Literature

Coppen, J.J.W., 1995. Flavours and fragrances of plant origin. Non-wood Forest Products 1. FAO, Rome, Italy. pp. 7-17.
Ibrahim bin Jantan, Wiselius, S.I., Lim, S.C. & Sosef, M.S.M., 1995. Cinnamomum Schaeffer. In: Lemmens, R.H.M.J., Soerianegara, I. & Wong, W.C. (Editors): Plant Resources of South-East Asia No 5(2). Timber trees: Minor commercial timbers. Backhuys Publishers, Leiden, the Netherlands. pp. 130-140.
Plucknett, D.L., 1978. Cassia - a tropical oil crop. Hawaiian Agricultural Experiment Station Journal Series 2345, Hawaii.
Purseglove, J.W., Brown, E.G., Green, C.L. & Robbins, S.R.J., 1981. Spices. Vol. 1. Longman, Harlow, Essex, United Kingdom. pp. 100-173.
Richard, H.M.J., 1991. Spices and condiments I. In: Maarse, H. (Editor): Volatile compounds in foods and beverages. Marcel Dekker, New York, United States. pp. 411-447. |6| van Hall, C.J.J. & van de Koppel, C. (Editors), 1946-1950. De landbouw in de Indischen Archipel [Agriculture in the Indonesian Archipelago]. Vol. 3. van Hoeve, 's-Gravenhage, the Netherlands. pp. 746-762. |7| Weiss, E.A., 1997. Essential oil crops. CAB International, Wallingford, Oxon, United Kingdom. pp. 155-179. |8| Yasaki, K. & Okuda, T., 1993. Cinnamomum cassia Blume (cinnamon): in vitro culture and production of condensed tannins. In: Bajaj, Y.P.S. (Editor): Biotechnology in agriculture and forestry 24. Medicinal and aromatic plants V. Springer Verlag, Berlin, Germany. pp. 122-131.

Sources of illustrations

Cinnamomum burmanni: Brown, W.H., 1941--1943. Useful plants of the Philippines. Vol. 1. Department of Agriculture and Natural Resources. Technical Bulletin 10. Bureau of Printing, Manila, the Philippines. (reprint, 1951--1957). Fig. 244, p. 576 (stamens, staminode); Cammerloher, H., 1925. Die Cinnamomum-Arten von Niederländisch-Ostindien [The Cinnamomum species of the Dutch East Indies]. Contributions à l'étude de la flore des Indes Néerlandaises 7. Bulletin du Jardin Botanique Buitenzorg, Series 3, 7: 446--496. Fig. 1, p. 451 (flowering branch, flower); Koorders, S.H. & Valeton, T., 1913--1918. Atlas der Baumarten von Java [Atlas of the tree species of Java]. Trap, Leiden, the Netherlands. Fig. 206 (fruits). Redrawn and adapted by P. Verheij-Hayes.

Authors

Nguyên Kim Dao, Tran Hop & J.S.Siemonsma