DISTRIBUTION

It is found in lowland to upland dry evergreen forests, primarily on some of the wetter mountain slopes in the northern part of Tanzania. In Arusha it grows in the mountain forests on the southeastern slopes of Mt. Meru, and is scattered on the slopes of Mt. Kilimanjaro (RSCU 1992).

Status: Needs to be well-managed to avoid becoming rare.

REQUIREMENTS

Soil Requirements: Prefers deep, loamy, fertile soils with good drainage. It is also found on fertile but powdery volcanic soils and deep rich loams (Watkins 1960).

Minimum Altitude (m): 750
Maximum Altitude (m): 2600
Minimum Rainfall (mm): 800
Maximum Rainfall (mm): 1200
Minimum Temperature (C): 14
Maximum Temperature (C): 18

Light Requirements: Shade tolerant when young.

Influential Factors: Normally immune to termites. It suffers from severe browsing by buck and duiker but recovers well.

PROPAGATION

Means of Propagation: Wildlings, seed, transplants, and striplings.

Seeds per kg: 3000
Germination Rate (%): 35
Germination Length: 2-6 months
Seed Sources: 2000 TSH per kg - Tanzania National Seed Centre 1991.

Seed Treatments: Fruit is small (< 1 cm), round, and hard, containing 1 seed per fruit. Collect ripe fruits from the ground or trees. Fruits are produced every 2 to 7 years. Soak in cold water for 48 hours to clean off all pulp, then dry in the sun for 5 days. Seed stores up to 3 months. It was noted that the seeds digested by wild pigs and bush doves germinated in 4 to 6 months. A large portion of the seed is fertile and in the forest seedlings are abundant.

Seedling Management: Germination rate seems to be low and irregular; between 2 and 9 months, with 3 to 5 months the average. Germination can occur as late as 2 years after sowing (Forest Division 1984). Seed storage requires refrigeration at low temperatures (3 degrees C). Many seedlings die off as a result of disease and damping off (Palmer and Pitman 1972).

SILVICULTURE

Planting Types: Grown in plantations in the highlands in clusters at close spacing and in combination with Grevillea robusta or other mixtures. It is recommended as an agroforestry species in Tanzania. It is said to not interfere with crops (Teel 1984).

Growth Factors: Growth is reported to be fast in young plants but much slower in older trees. Volumes from well-established stands have been recorded to be about 20 m3 per ha for a 25 to 30 year period (periodic MAI) (Forest Division 1984).

Growth Cycle: Rotation length is 75 years.

Limitations to Planting: A plantation in Usa was totally destroyed by elephant browsing.

Management Systems: Planting should be done during the wettest part of the year. It is necessary to reduce the risk of browsing damage by outplanting tall seedlings (1.8 m) with all the lower leaves stripped off and only the terminal pair remaining (Forest Division 1984). It can be planted in groups with Grevillea robusta serving as a nurse tree at a spacing for Grevillea of 2.4×2.4 m and about 9 plants of O. capensis, with an internal spacing of 1×1 m. It can be planted at intervals of 7 to 8 m. It tolerates lopping, pollarding, and coppicing.

IMPORTANT USES

Use #1: FUELWOOD
Firewood from O. capensis is reported to be the best in Tanzania. It also makes excellent charcoal.

Use #2: TIMBER
The timber is heavy, strong, durable, and termite resistant. It is used extensively for heavy construction purposes, veneers, building materials, and furniture. Planting in groups at close spacing produces a good source of withers, and well formed trees can be used for timber.

Use #3: FODDER
O. capensis is a useful fodder tree as the pods, seeds, and leaves can all be used for this purpose.

OTHER USES: The bark is used in local medicine.

Authors: Deborah A. Hines & Karlyn Eckman, 1993

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