Oxytenanthera abyssinica

Cultivation Details

A plant of the drier to moist tropics, but avoiding the humid zones, it is found at elevations up to 2,000 metres, but mainly at 300 - 1,500 metres^[2]. It occurs in savannah woodland areas subject to a climate with an average annual rainfall of over 800 mm and 3 - 7 dry months (where the average rainfall is less than 50 mm). It is absent from closed forest and extends little into semi-arid wooded grassland and thicket. Prevailing average annual temperatures are 20 - 27°c, with monthly average daily maxima of 30 - 36°c and daily minima of 7 - 17°c. Locally occasional frost may occur; if severe, this may scorch leaves^[2]. Succeeds on a range of soils so long as they are moisture retentive and also well-drained^[2]. Clumps take up to 6 years (from rhizome offsets) or 8 years (from seedlings) to reach the stem harvesting stage^[2]. A pure stand of Oxytenanthera abyssinica contains up to 750 clumps and 30,000 stems per ha^[2]. A newly germinated seed produces a single shoot in the first year, which may reach 1 metre in height from a small rhizome. By the third year, several shoots 1.8 - 3 metres long and 12mm in diameter can be produced from a rhizome that is 30cm long^[2]. The plant reaches full height and diameter within 4 - 8 years^[2]. Bamboos have an interesting method of growth. Each plant produces a number of new stems annually - these stems grow to their maximum height in their first year of growth, subsequent growth in the stem being limited to the production of new side branches and leaves. In the case of some mature tropical species the new stem could be as much as 30 metres tall, with daily increases in height of 30cm or more during their peak growth time. This makes them some of the fastest-growing species in the world^[PFAF]. New stems break through the soil surface in the rainy season, growing very quickly for their first 3 - 4 weeks then slowing down and reaching their final height after 2 - 4 months^[2]. Canes mature in 3 years, and may survive for 8 years, but they are over-mature and unsuitable for harvesting from 6 years of age onwards^[2]. Clumps of plants grown for sap production are thinned from the second year onwards to prevent stem congestion, while pruning branches to around 2 metres favours access, and loosening peripheral soil promotes rhizome extension and unhindered shoot emergence^[2]. Bamboos in general are usually monocarpic, living for many years before flowering, then flowering and seeding profusely for a period of 1 - 3 years before usually dying. Clumps can live for 30 years, but this is less when mass flowering occurs and rhizomes die with the stems. Mass flowering can occur every 7 years in Uganda, 14 years in Zambia or 20 - 21 years in Malawi, whilst sporadic flowering of individual plants has been widely and frequently noted^[2]. Sometimes clumps die after mass flowering, but in other instances they have been known to survive by sending up new canes from the rhizome^[2].