Vitex (PROSEA Timbers)

Plant Resources of South-East Asia Introduction

List of species

Vitex L.

Protologue: Sp. pl. 2: 638 ("938"; 1753); Gen. pl. (Ed. 5): 285 (1754).

Family: Verbenaceae

Chromosome number: x= 6, 8; V. altissima: n= 12, V. negundo: 2n= 24, 32, V. quinata: n= 16.

Trade groups

Vitex: medium-weight to heavy hardwood, e.g. Vitex altissima L.f., V. cofassus Reinw. ex Blume, V. glabrata R.Br., V. parviflora A.L. Juss., V. pinnata L., V. quinata (Lour.) F.N. Williams.

Vernacular names

• Vitex
• Indonesia: gupasa, laban (general), ketileng (Java), serawet (Sulawesi)
• Malaysia: leban (Peninsular, Sarawak), kulim papa (Sabah)
• Papua New Guinea: garamut
• Philippines: molave, bongoog
• Burma (Myanmar): kyetyo
• Thailand: tinnok
• Vietnam: bình linh.

Origin and geographic distribution

Vitex consists of about 150 species and is distributed throughout the tropics and subtropics with a few species in temperate regions. About 30 species occur in Malesia, but only about 8 reach a size which makes them useful for timber. Some shrub-sized species (e.g. V. negundo L. and V. trifolia L.) are widely cultivated as ornamentals and hedge plants and sometimes naturalized.

Uses

Vitex timber is used for high-grade construction, interior finishing, flooring, window frames, ship building, wagons and carts, sleepers, railway ties, buffalo yokes, cogwheels, docks, fence posts, paving blocks, furniture, agricultural and household implements, sculpture and carving. The wood is sometimes also used for canoes, cabinets, furniture, carving, tools and toys; it serves as firewood.

A decoction of the wood and bark has medicinal properties, and is particularly used as febrifuge. Some species may produce a fish poison and others a yellow dye, whereas a few species have edible fruits.

Production and international trade

Vitex timber enters the international trade market in very small amounts from South-East Asia. It is mostly used locally, but has at least someimportance as an export timber in Papua New Guinea and Irian Jaya. In Papua New Guinea, it is ranked in MEP (Minimum Export Price) group 3, which in 1992 fetched a minimum price for saw logs of US$ 50/m³. However, fairly large amounts of Vitex timber are exported from the Solomon Islands, mainly to Japan.

Properties

Vitex wood is medium-weight and moderately hard to heavy and hard. The heartwood is pale straw-coloured or greyish to pale brown or yellowish-brown, sometimes greenish-brown, and usually not very distinct from the sapwood which is slightly paler and 4-8 cm wide. The density is (340-)520-940(-1010) kg/m³at 15% moisture content. The grain is straight or slightly interlocked or wavy, texture fine to moderately fine and even. Freshly-cut wood of V. cofassus has a leathery scent.

V. cofassus wood from Papua New Guinea tested at 12% moisture content showed the following mechanical properties: the modulus of rupture 113 N/mm², modulus of elasticity 13 600 N/mm², compression parallel to grain 64 N/mm², compression perpendicular to grain 10.5 N/mm², shear 16.5 N/mm², cleavage 61 N/mm tangential, Janka side hardness 5520-5650 N and Janka end hardness 6140 N. A test on V. parviflora wood from the Philippines showed the following mechanical properties at 40% moisture content: the modulus of rupture 92 N/mm², modulus of elasticity 12 840 N/mm², compression parallel to grain 42 N/mm², compression perpendicular to grain 10 N/mm², shear 10 N/mm², Janka side hardness 6135 N and Janka end hardness 5695 N.

The wood usually seasons well with little degrade, provided stacks are weighted down, and with little to moderate shrinkage. Shrinkage of V. cofassus wood from green to 15% moisture content is 0.9-1.5% radial and 2.6-3.6% tangential, from green to 12% moisture content about 1.8% radial and 4.1% tangential, and from green to oven dry 3.5-4.2% radial and 6.8-8.0% tangential. Wood of V. parviflora shrinks 2.3% radial and 3.6% tangential from green to 15% moisture content, and 5.4% radial and 7.7% tangential from green to oven dry. Kiln drying from green condition to 12% moisture content takes 9-10 days, and after preliminary air drying to 25% moisture content about 4 days. Checking of V. cofassus wood may be severe during kiln drying. Warping may develop in back-sawn boards, but weighting of stacks and close spacing of stickers may prevent this. A high-humidity treatment is recommended after drying to relieve stresses. Once dry, the wood is stable in service.

In spite of its comparatively high density, the wood is easy to work as it contains no silica. It planes and machines well and a good finish can be obtained. It is rather difficult to split and nail, but it holds nails well and can be polished to a very smooth surface. The gluing and painting properties are variable. The steam bending properties are good. V. cofassus wood is probably not suitable for slicing because of discoloration and some difficulties in cutting. For peeling the logs should be heated, whereas the irregular, fluted logs may cause problems.

Vitex wood is durable, even when used outside and in contact with the ground; stakes may last over 5 years under tropical conditions. It is fairly resistant to fungal, termite and Lyctus beetle attack, but not to marine wood borers. The heartwood is difficult to treat with preservatives and the sapwood moderately difficult; in a test using wood of V. cofassus and a pressure treatment the heartwood absorbed only 32 kg/m³of preservative and the sapwood 172 kg/m³.

Wood of V. parviflora contains 73% holocellulose, 36%α-cellulose, 39% lignin and 1.6% ash. The solubility is 7.8% in alcohol-benzene, less than 1% in cold water, 2.3% in hot water and 7.0% in a 1% NaOH solution.

A yellow extract is obtained when shavings are soaked in water for a few hours, and a yellow resin exudes when the wood is treated with lime. The wood often takes on a yellowish-green or greenish-brown tint when boiled in water, and it has an appreciable flavone content.

Description

Shrubs and small to medium-sized trees, sometimes large, up to 45 m tall, with crooked or straight bole, up to 125(-200) cm in diameter, usually without buttresses but sometimes with distinct buttresses, often strongly fluted; bark surface rather smooth, shallowly fissured or flaky, pale grey to pale yellowish-brown, inner bark pale yellow to bright orange; crown often spreading. Leaves opposite, palmately compound with 1-7(-9) leaflets (leaves seemingly simple in V. cofassus with only one leaflet present, but articulation present in petiole), without stipules. Flowers in a terminal panicle or axillary cluster, bisexual, zygomorphic; calyx cup-shaped, with 5 lobes; corolla with a short tube, 2-lipped, upper lip 2-lobed, lower lip much larger and 3-lobed, pubescent outside; stamens 4, inserted on the corolla tube, exserted, didynamous; ovary superior, 2-4-chambered, with 1 filiform style having a bifid stigma. Fruit a juicy or dry drupe, sessile on the often enlarged calyx, 1-4-seeded. Seed obovoid or oblong, lacking endosperm. Seedling with epigeal germination; cotyledons green and leafy; leaves opposite, conduplicate, first ones simple, margins toothed.

Wood anatomy

• Macroscopic characters:

Heartwood greyish-white, grey, yellowish-grey, olive-grey or purplish-grey, through shades of reddish or olive-brown to brown, not distinctly demarcated from the sapwood. Grain straight, or more or less wavy on radial surfaces. Texture moderately fine to fine; the wood is dull to slightlylustrous, and without characteristic odour or taste. Growth rings distinct, but inconspicuous, generally 2-5/cm; vessels medium-sized to small, usually invisible or hardly visible to the naked eye; parenchyma relatively sparse, sometimes visible as very narrow bands; rays moderately fine to fine, just visible or not visible to the naked eye, inconspicuous on radial surfaces; ripple marks absent.

• Microscopic characters:

Growth rings usually distinct, demarcated by denser fibrous tissue in the outer portion of the growth ring and frequently by a narrow line of parenchyma or by larger earlywood vessels. Wood diffuse-porous or semi-ring-porous; in the latter case vessels largest in the inner third of the growth ring, quite evenly distributed, 10-26(-31)/mm², predominantly solitary and in radial rows of 2-4, rarely in longer rows or clusters, generally oval, average maximum tangential diameter 120-180μm; perforation plates simple; intervessel pits alternate, numerous, oval to rounded or hexagonal, 6-10μm in diameter; vessel-ray pits numerous, with reduced borders to simple, oval or round, 5-11μm in diameter; gummy inclusions occasionally present, white deposits sometimes occluding the vessel segments; tyloses abundant or sparse. Fibres 0.5-1.6 mm long, thin-walled to medium thick-walled, septate, with simple, slit-like pits, mainly confined to the radial walls. Parenchyma scanty, paratracheal to vasicentric, sometimes scanty apotracheal diffuse and in narrow marginal bands, in 3-6-celled strands. Rays 5-7(-10)/mm, mostly multiseriate, 1-4(-6) cells wide, up to 1.8 mm high, homocellular with all cells procumbent or weakly heterocellular. Crystals prismatic, usually 1-2 per cell in ray parenchyma cells; gummy deposits scarce to abundant in parenchyma and ray cells and in fibres. Silica absent. Axial intercellular canals absent.

Species studied: V. altissima , V. leucoxylon L.f., V. peduncularis Wallich, V. pinnata , V. quinata .

Growth and development

Young Vitex trees grow moderately slowly. V. altissima showed a mean annual diameter increment of 0.6 cm in Burma (Myanmar), V. glabrata 0.8 cm in Burma (Myanmar), V. parviflora 0.7-1 cm in the Philippines, V. pinnata 0.6 cm in Burma (Myanmar) and slightly over 1 cm in Java, and V. quinata 1.2 cm in Java. One-year-old seedlings of the last two species may reach 2 m in height in East Java, and the mean annual height increment for the first 15 years after planting is 1 m. The mean annual height increment of V. parviflora in the Philippines is recorded as much less, only 0.4 m, although in some plantations a height growth of over 1 m/year has been reached.

The crown often covers more than half of the total height of the tree and is wide spreading, and sheds its leaves partially or entirely during the later part of the dry season. However, most species are evergreen. The trees usually flower in the rainy season and fruits ripen within a few months. Planted V. parviflora trees have been observed to start flowering 5-6 years after planting, but in Java trees of V. pinnata and V. quinata do not start to flower until 11-12 years old.

Other botanical information

Vitex is usually placed in the subfamily Viticoideae together with Callicarpa , Clerodendrum , Gmelina , Premna and Tectona . Premna is probably most closely related, but can be distinguished by its simple leaves and very small flowers. Teijsmanniodendron is very similar to Vitex . It differs in the swollen stalk apices of leaves and leaflets. In general, Vitex species can be recognized easily by their opposite, palmately compound leaves (but 1-foliolate in V. cofassus ) and their indehiscent fruits seated on the persistent calyx. Viticipremna philippinensis (Turcz.) H.J. Lam, the timber of which is used in the Philippines, is often treated under the synonym Vitex turczanihowii Merr.; it differs in the 4-merous corolla.

Ecology

Vitex occurs most commonly in comparatively dry regions in lowland forest, often in deciduous forest on rocky ground, on grassy slopes and on dry limestone soils, but sometimes also in littoral rain forest or hill forest, occasionally up to 2000 m altitude. It is usually found in regions with distinct wet and dry seasons. Vitex species often occur gregariously in secondary forest (e.g. V. pinnata ). V. pinnata is a pioneer tree species and may grow in alang-alang ( Imperata cylindrica (L.) Raeuschel) vegetation and may even occur in recently burnt grasslands (e.g. in South Kalimantan); it is moderately fire-resistant. In primary forest, Vitex is found in places with little overhead shade such as river banks and gaps. V. parviflora occurs in the Philippines in secondary forest and open primary forest in association with Intsia , Pahudia , Sindora , Toona and Wrightia species. V. cofassus may predominate together with Pometia pinnata J.R. Forster & J.G. Forster in forest in Papua New Guinea, and associated with Araucaria , Elmerrillia and Spondias species.

Propagation and planting

The number of seed per kg is 10 000-12 000 for V. pinnata , about 10 500 for V. cofassus , 10 000-18 000 for V. parviflora , and about 7000 for V. quinata . Seed starts to germinate 10-40 days after sowing, and germination rates differ between the species: 60-80% for V. pinnata , 25-35% for V. parviflora and only 0-20% for V. cofassus . Removing the pericarp and soaking the seed in hot water (70C) may enhance the germination rate considerably; up to 70% for V. parviflora and V. cofassus . V. pinnata seed can be stored for one year, provided the pulp is removed. Dark brown fruits of V. parviflora are ripe and ready for seed collection; ripe fruits should be collected from the trees.

Seed of V. cofassus is sown 1 cm apart in rows 15 cm apart or broadcast, and covered with 1 cm ofsoil. Mulching of the seed-bed is recommended to reduce evaporation during the dry season. V. pinnata does not need shade in the nursery to obtain a high germination rate.

Propagation by stumps and wildlings is also practised, but the production of stem cuttings has not been very successful to date. The use of stumps was recommended for V. cofassus in Sulawesi (Indonesia) because it does not regenerate very well under natural conditions, which makes it difficult to collect large numbers of wildlings. Root suckers are produced, but it is not known whether these can attain a size required for quality timber.

Under a dense forest canopy, the germination of V. pinnata is completely inhibited, but seed remains dormant and viable for more than 6 months. Seed under light shade differentiates into two fractions: one fraction with seed germinating within 2 months, the other one with seed remaining dormant and only germinating when exposed to full sunlight.

Planting should be done early in the rainy season. Generally V. cofassus , V. pinnata and V. quinata are planted at 1 m × 3 m in Java, occasionally at 1 m × 1-2 m on very fertile soils. In the Philippines, V. parviflora is generally planted using bare-rooted seedlings at 2 m × 2 m, but plantations for wildling production are spaced 2 m × 6 m. Spacings have not been tested for maximum stand development in plantations.

Silviculture and management

Survival of young trees is enhanced by removing weeds 3-4 months after planting and from then on annually up to 10 years. V. parviflora is suggested for the Philippines as a tall tree in shelterbelts. Vitex is not very sensitive to the effect of fire.

Diseases and pests

Vitex trees are not very susceptible to attacks of wood fungi. In the Philippines and Java, however, some insect pests are known to cause serious damage to 9-25-year-old trees. The most prevalent and destructive insect is the carpenter moth ( Xyleutes ceramicus ). Its larvae may damage the cambium of trunk and branches. Mixed planting with resistant species is recommended.

It is undesirable to have Vitex near teak plantations as it serves as an alternative food plant for Hyblaea purea (teak defoliator) at the time teak is leafless.

Beetles of Leucopholis irrorata and Anomala sp. and an unidentified Melothonthid beetle have been observed to defoliate V. parviflora . Young trees of V. pinnata in Java were attacked by black bug ( Tingide spp.) and young leaves and branches of V. quinata by Zeuzera coffea . Cromerus kalshoveni , a top-sucking insect ("tip wilter") has been observed on V. quinata , whereas larvae of Chalcolampra pustulata bore into the shoots of V. pinnata .

Harvesting

Trees may attain the required dimensions for sawn timber in 60 years. Sustainable management of natural Vitex forest is recommended by selectively logging and harvesting trees with a minimum diameter of 35 cm. In addition, manual felling and the use of cables for yarding are recommended. Brittle heart may be present in logs as is the case in V. cofassus ; it is about 15 cm in diameter.

Yield

A 29-year-old plantation of V. parviflora in the Philippines planted at 2 m × 2 m yielded 76 m³/ha (mean annual increment 2.6 m³/ha). A 15.5-year-old plantation of V. quinata in Java, spaced at 1 m × 3 m on fertile soil yielded 84 m³/ha of clear-bole timber (mean annual increment 5.4 m³/ha), whereas a 13.5-year-old plantation of V. pinnata on fertile soil produced 53 m³/ha (mean annual increment 3.9 m³/ha). A 10-year-old plantation of V. cofassus on fertile soil yielded only 8 m³/ha (mean annual increment 0.8 m³/ha). All yields are irrespective of wood from thinnings. The timber volume of a clear bole of V. cofassus is about 2.3 m³.

Genetic resources

Most Vitex species do not seem to be readily liable to genetic erosion as they are widespread and generally regenerate easily and abundantly after disturbance of the forest. However, some species which occur only very locally may become more easily endangered, e.g. V. erioclona H.J. Lam, an endemic and rare species of Sulawesi, the wood of which is reportedly favoured for boats and building materials, and V. urceolata Clarke, a rare tree in Peninsular Malaysia. In 1960 V. parviflora was considered to be nearly extinct in those areas in the Philippines where it used to abound, because of its extensive utilization for house construction and railway ties. Nowadays, it is one of the protected species in the Philippines.

Appreciable variation in wood characteristics in some species is reflected in the different vernacular names local people give the various forms, e.g. for V. cofassus in the Moluccas and for V. quinata in Sulawesi.

Prospects

Although Vitex trees are rather slow-growing, planting may be worth while as they produce high-quality timber and can be planted successfully in dry areas. Vitex is not recommended for large-scale plantations because there is still a lack of knowledge on aspects of silviculture, vegetative propagation and breeding. Research on these aspects is desirable.

Literature

• Aminuddin, M. & Ng, F.S.P., 1982. Influence of light on germination of Pinus caribaea, Gmelina arborea, Sapium baccatum and Vitex pinnata. Malaysian Forester 45(1): 62-68.
• de Guzman, E.D., Umali, R.M. & Sotalbo, E.D., 1986. Guide to Philippine flora and fauna. Vol. 3: Dipterocarps, non-dipterocarps. Natural Resources Management Center, Ministry of Natural Resources and University of the Philippines, Manila. pp. 362-363.
• Fundter, J.M. & Wisse, J.H., 1977. 40 belangrijke houtsoorten uit Indonesisch Nieuw Guinea (Irian Jaya) met deanatomische en technische kenmerken [40 important timber species from Indonesian New Guinea (Irian Jaya) with their anatomical and technical characteristics]. Mededelingen Landbouwhogeschool Wageningen 77-9: 205-209.
• Garcia, M.U., 1980. Effect of pericarp removal on the germination of molave (Vitex parviflora Juss.) seeds. Sylvatrop 5(1): 61-66.
• Kochummen, K.M., 1978. Verbenaceae. In: Ng, F.S.P. (Editor): Tree flora of Malaya. A manual for foresters. Vol. 3. Malayan Forest Records No 26. Forest Research Institute Malaysia. Longman Malaysia SDN. Berhad, Kuala Lumpur. pp. 297-313.
• Lam, H.J., 1919. The Verbenaceae of the Malayan Archipelago, together with those from the Malayan Peninsula, the Philippines, the Bismarck Archipelago and the Palau-, Marianne- and Caroline-Islands. M. de Waal, Groningen, the Netherlands. 370 pp. + 3 plates.
• Leafblade, C.F., 1981. Basic research to explain why depulping of molave seeds enhances their germination. Canopy International 7(10): 10-11.
• Maun, M.M., 1960. Silvical characteristics of molave (Vitex parviflora Juss.). Philippine Journal of Forestry 16(1-2): 95-110.
• Reyes, L.J., 1938. Philippine woods. Technical Bulletin No 7. Bureau of Printing, Manila. pp. 432-437.
• Seran, D., 1987. Percobaan penanaman Vitex cofassus Reinw. pada daerah dataran rendah di kompleks hutan Andi Pangerang Pettarani, Pare-Pare, Propinsi Sulawesi Selatan [Trial on the cultivation of Vitex cofassus Reinw. in the lowland area of the Andi Pangerang Pettarani Forest Complex, Pare-Pare, South Sulawesi]. Jurnal Penelitian Kehutanan (Ujung Pandang) 1(1): 9-16.