Agroforestree Database

Local names:
 English (mkanyi fat,kagne butter), Swahili (mwaka,mshambe,mkimbo,mkanye,mkani,mkange)

Allanblackia stuhlmannii is a tall evergreen forest tree to 40 m tall, with a
straight, occasionally buttressed bole. The branches are usually drooping and often conspicuously whorled. Bark dark grey or black, sometimes smooth or with rough squares scales. The slash is red with white stripes, fibrous/ granular, exuding a clear exudate latex, which later turns yellowish.

Leaves simple, opposite, deep green, 5-19.5 cm long by 1.2-7 cm wide; oblong or elliptic elongated, abruptly and sharply acuminate, cuneate at the base; with many pairs of very thin lateral nerves running at a wide angle to the midrib; stalk stout, 1-2 cm long.

Flower large, waxy, unisexual, usually solitary in axils, very fragrant, up to 5 cm across when expanded and 1.5 cm across in bud form. Stalk 6-8 cm long with 5 unequal overlapping, rounded and concave red or pale yellow sepals. Petals 5, cream or scarlet rounded about 2 cm long. Male flowers in a terminal raceme, crowded towards the apex of the drooping branches. Anthers on both faces of stamen bundles. Stamen-bundle flattened, club-like, yellow, and waxy, about 1.5cm long. Female flowers with stamens reduced to staminodes; ovary ovoid, 1.5 cm long, glabrous with 2-4 ovules per locules, arranged in 2 rows; with the large 5-lobed stigmas forming a cap over the apex.

Fruit is a large ovoid 5-lobed drupe, 16-34 cm long by 15-17 cm wide with tough flesh, brown or red-brown, oblong or subglobose, producing a yellow latex, hanging at the end of a short stalk.

Seeds brittle-shelled, four-angled, about 4 cm long by 3 cm wide, 40-100 per fruit, embedded in a gelatinous pulp.

The generic name ‘Allanblackia’ is after a 19th-century Kew botanist, Allan Black.

There are 9 species in the genus Allanblackia accepted according to Bamps (1969). These are A. ulugurensis Engl., A. stuhlmannii Engl. (endemic to East Africa), A. kisonghi Vermoesen, A. kimbiliensis Spirl  (endemic to Congo-Kinshasa). The rest such as Allanblackia floribunda Oliv., A. parviflora A.Chevalier, A. gabonensis (Pellegr.) Bamps, A. marienii Staner, A. stanerana Exell & Mendonca occur in several countries of Central Africa.

Ecology

A. stuhlmannii is found in intermediate evergreen montane rain-forest on seaward slopes of Usambara, Nguru and Ulunguru mountains associated with Cephalosphaora usambarensis, Newtonia buchanannii, Beilschmedia kweo, Parinari excelsa, Myrianthus arboreus, Isoberlinia scheffleri and Macaranga kilimandscharica.

Native range
Tanzania

Tree management

This is a potential plantation species that should be grown in full sun on well-drained soil.

Mature fruits fall on the ground from which they can be collected. The fruit is opened. In freshly fallen fruit the flesh inside is fairly tough; but as fruit decays, its toughness decreases. The seeds are extracted from decaying tissues and dried in the sun. The seed storage behaviour is recalcitrant. There are about 100 seeds/kg.

A. stuhlmannii is found in intermediate evergreen montane rain-forest on seaward slopes of Usambara, Nguru and Ulunguru mountains associated with Cephalosphaora usambarensis, Newtonia buchanannii, Beilschmedia kweo, Parinari excelsa, Myrianthus arboreus, Isoberlinia scheffleri and Macaranga kilimandscharica.

A. stuhlmannii regeneration occurs in natural forest although few seedlings reach sapling stage due to fruit borers such as the giant rats (probably Cricetomys emini),  excessive seed collection for oil extraction and sporadic, prolonged germination, which exposes the seed or seedling to detrimental environmental elements.

Very little has been done to raise the tree vegetatively. No seed pre-treatment is required during sowing. The germination starts at four to five months and continues sporadically for two to three months like other recalcitrant species which exhibit delayed germination eg. Strychnos cocculoides, Xymalos monospora and Ocotea usambarensis. The use of wildings for potting is another alternative although poor survival rate has been reported. Grafting and wildings has been tried with success in the Usambaras.

 Seeds are pounded and cooked to extract an edible fat. In Amani (Tanzania), the seeds were extensively used as a butter substitute in manufacture of chocolate during the First World War. Recently, GAPEX company had been buying seeds at 2-3 Tshs per kilogram for oil extraction.

The bitter seedcake is used as an animal feed

Apiculture: The Tree is a bee-forage 

Timber: The wood has timber value and is used in furniture, boxes, crates, beehives and water containers.

Shade or shelter: The tree is used for shade and amenity.

Tannin or Dyestuffs: The bark produces a yellow dye.

Lipids: Seeds yield an edible fat used in cooking, lighting and liniment. Seed kernels amount to 60-80% of the whole seed weight. The unusual hard white fat consists of 52-58% stearic acid and 39-45% oleic acid. It therefore has a considerable attention, based on its unusual fat composition.

Medicine: Fresh leaves are chewed to cure coughs. The oil from seeds is drunk in small quantities twice a day for rheumatism. Leaves and roots are used as medicine for impotence.