English/Common name- Senna siamea, Bombay blackwood
Local name- कसोद, Bombay blackwood, Ironwood,
Botanical name- Siamese cassia
Appearance- Senna siamea is an evergreen, medium-sized many-branched tree legume. It reaches 10- 12 m on average, rarely exceeding 20 m, and can exceptionally reach 30 m. Its root system consists of few thick and deep roots and in a dense mat of rootless roots that spreads rapidly up to 7 m in one year. Siamese Senna is easily uprooted by strong winds. The trunk is straight, up to 30 cm in diameter, with a rounded and dense crown. The bark is grey to light brown, becoming fissured with age. The leaves are alternate, 10- 35 cm long, pinnately compound with 6-14 pairs of leaflets. Leaflets are oblong in shape, 3- 7 cm long and 1.2 – 2 cm in breadth, dark green in color with a midrib ending in a short bristle.
Origin- Bombay blackwood tree is a legume in the subfamily of Caesalpinioideae, native to South and Southeast Asia.
Conditions required for growth- Siamese senna can be sown directly or in containers and then planted. It should be sown in line to a depth of 4-5 cm. After germination, the seedlings should be thinned to a spacing of 30 cm at the end of the first rain and then to 1.8 m x 1.8 m in the following rainy season. Siamese senna grows very fast: in India, a height increment of 2.5 m per year has been recorded. In West Bengal, 3-year old trees were almost 8 m tall with a stem girth of 25 cm. Suitable for: light (sandy), medium (loamy), and heavy (clay) soils, prefers well-drained soil and can grow in nutritionally poor soil. Suitable pH: acid, neutral, and basic (alkaline) soils and can grow in very acid soils.
Uses- Senna siamea is grown for fodder and browsed by livestock. The fruits and leaves are used for food as vegetables or in curries but cooking water should be replaced 3 times to reduce undesirable substances. Though it produces some smoke, the wood can be used as fuelwood to make high-grade charcoal. It’s used to make poles, posts, bridges, mine timbers, and heartwood for cabinet-making joinery and other decorative purposes
Hazards- In any case, it should only be used for feeding ruminants, as its flowers, leaves, and pods foliage contain alkaloids and anti-nutritional compounds that are toxic to non-ruminants such as pigs and poultry, which should be kept away from the plantations.
