Senna siamea (Lam.) Irwin & Barneby
Cassod tree, Kasia, Siamese cassia
|Author: Le Houérou|
Small to medium sized tree, originating in the Asian tropics, up to 15-20 m tall, but 5-10 m in the Sahel., with a short bole and low branching high crown. Leaves bipinnate, alternate, rachis 25-30 cm long, with a marked furrow, 8-13 pairs of leaflets of different size. Leaflets oblong, rounded at the base and at the apex, slightly retuse. Upper side dark green and shining, underside dull-green, shortly haired. Flowers yellow, up to 3..5 cm long, in dense racemes at the end of the shoots, and in their axils. Racemes 15-30 cm long. Glabrous, brown, slightly curved pods in dense clusters, up to 25 cm long with ca 20 seeds in each
Water requirement is 500 to 1500 mm of MAR.
In the Southern Sahel it needs deep fresh soils in this region, and preferably the presence of a water table.
Originates in India, Burma, Sri Lanka, Indonesia and Malaysia. Today pantropical in semi-arid and subhumid tropics.
Propagation by seeds, stumps and nursery-grown seedlings.35,000 to 40,000 seeds per kg. Seeds remain viable for 2-3 years under the Sahel conditions. Seeds germinate readily without treatment, but older seeds must be scarified, seedlings and young trees are very sensitive to fire, root system liable to damage from various insects.
Hardly used in afforestation in the Sahel, but in the Sudanian ecozone it is a rather fast growing species for the production of pole timber and fuelwood, regenerates vigorously by coppicing, rotation of 4-7 years for pole production. Used as fuelwood throughout the Sahel., wood fairly heavy with a specific gravity of 0.6-0.8, hard , splits easily, rapidly attacked by insects. Heartwood dark almost black with yellow streaks. When in appropriate size suitable for furniture, turnery and cabinet work ; poles and posts are widely used. Leaves and pods are browsed by ruminants but highly toxic to pigs and possibly to other monogastrics. Suitable for shelterbelt plantations, but not as shade tree in agroforestry because of root competition. Roadside and courtyard planting in the South Sahel., widely used as ornamental and line-planting, villages and squares in the Sudanian ecozone. The heartwood has laxative properties and is used for a variety of ailments, of blood forming organs, genito-urinary tract, also for herpes and rhinitis. Leaves are said to be poisonous.