Brachylaena hutchinsii O. Hoffm.

Brachylaena huillensis grows to 35 m tall with a dbh of 85 cm under favourable conditions; fluted and often curved bole, which makes it difficult to obtain large dimensions of timber; bark grey, smooth or rough with longitudinal cracks. Leaves entire or dentate, oblanceolate, up to 13 cm long and to 2.5 cm wide, grey felty beneath; apex acute; base long cuneate; petiole 1.2 cm long. Capitula small, white, cylindrical, up to 2.5 cm long, in axillary woolly panicles; male capitula shortly pedicellate, with about 12 flowers; female capitula subsessile, with about 5 flowers; pappus in 1 row of scrabid bristles; flower heads white, in small terminal panicles or racemes; flowers tubular or discoid. Fruit a small, winged achene in a white capitulum. On the flowers, the bracts surrounding the discs are shorter than the flowers and are the basis of the generic name, which is based on Greek words meaning ‘short’ and ‘cloak’. The specific name means ‘of Huilla’, a place in Angola.

B. huillensis is a dioecious plant. The male has 2-3 times as many capitula as the female in each branch of the inflorescence. The flowers are small, and dissection of newly opened flowers and buds just about to open reveals no nectar. Flowering coincides with the rainy seasons. In Kenya, B. huillensis flowers twice a year, between mid-April and the end of June and between mid-November and early January. The flowers develop slowly for the next 2-3 months until the next rainy season. Opening is delayed until the rains come, and should they fail, all the buds shrivel and the next season’s buds start to appear. Male flowers almost always open earlier than female one. Bees collect and feed on pollen, which is possibly the main attraction of these flowers. Other pollinators include small flies such as Aprostocetus spp., Eupelmus spp., Mesopolopus spp., Pteromalus spp. and Trupanea albicans. The period available for fertilization is brief, and the development and maturation of the fruit is very rapid. About 10-20% of the seeds are sound at dispersal.

Prefers deep, well developed, red, volcanic clayey loams in plateau forests and red soils in the coastal belts.

In Kenya, B. huillensis is common in semi-deciduous tropical forests of the central highlands and the lowland dry coastal belts. It is also found in the northern forests of Tanzania.

B. huillensis is normally propagated by seed. Seeds from fruits collected only 7 days after the maturation of the buds will germinate.

The trees are easy to raise in plantations. On average, growth increment is fast on good soils.

B. huillensis is notable for its high durability in the soil and resistance to fungal and insect attack. For example, it is resistant to the marine borer or shipworm, Teredo navalis.

Seed storage behaviour is uncertain; viability is lost within 6 months in open storage at room temperature. There are 333 000-500 000 seeds/kg.

Boundary or barrier or support: Due to its durability, B. huillensis is used as fence posts, for example in northern Tanzanian along the border with Kenya, where it is overexploited. Ornamental: B. huillensis is planted as an ornamental tree around dwellings in Kenya.

Fuel: During the 1st 2 decades of the 19th century, B. huillensis was the main fuel for Kenya. It was also exported as short logs to India as an inferior substitute for sandalwood for use in cremations. It is suitable for charcoal because of its high density, and is exploited for this in Kenya. Timber: The wood is pale yellow to pale brown, with characteristic storeyed structure, scented somewhat like sandalwood, straight grained with conspicuous growth rings; texture is very fine, even, strong and stiff. But its failure in bending is sudden and complete. It is hard to work but does turn and work well with sharp tools. It takes a high polish but splits easily along the grain. It is used in flooring, furniture and joinery. In Kenya, it is a favourite wood for carving artefacts. Essential oil: Oil distilled from the wood has a pleasant, vetiver-like perfume.