Albizia gummifera

Albizia gummifera has been called Peacock Flower but the Swahili name of Mkenge is more understood in Tanzania.

A tree endemic to East Africa but is also found in West Africa, Ethiopian Zaire and Madagascar. In Tanzania it is found in rainforest from around 600 m - 2 600 m above sea level. There was a very large tree behind out house at Makumira.

Description: A large deciduous [or partly deciduous] tree to 15 m, with branches ascending to form a flat top. Trunk diameter >1 m. Bark is grey and smooth. Leaves are shiny and dark green with leaflets being rectangular and the veins diagonal. Flowers white/pink clusters with prominent stamens. Fruits are pods in bundles and shiny brown, flat with raised edges >20 cm long [sometimes shorter] and 3 cm wide containing 8 - 41 flat, brown seeds.

Uses: Firewood, general use timber, household utensils [no taste to the wood], beehives, traditional medicine, fodder, bee forage, soil conservation, nitrogen fixation, shade, shelter.

Propagation: There are >15 000 seeds per kg which can be stored for a year if kept dry and insect free. Germination is quick, 4 -12 days and with a rate of >80%.
Fresh seed will germinate without treatment but stored seed will need cold water soaking for 12 hours, better though is to nick the seed coat.
In the pot the seedling grows well and needs [or performs best] shade when first out-planted.
The tree is fast growing in good conditions and will coppice.

The gum makes a lather/soap, but despite the name, gum is not harvested from the tree. The pale brown heartwood is reasonably strong and is easy to work.
The nectar in the flower attracts monkeys, and they eat the whole flower. Monkeys can be raiders and damage other crops.
The leaves quicken the ripening of bananas when layered in unripe fruit.
Generally it a an attractive tree.

Acacia xanthophloea

We did not grow Acacia xanthophloea in the nursery because the tree is associated with areas where there is a high water table, so we did not have areas to plant them - though they would be good at Muriet village.
The Swahili name is Mgunga but as well there are a number of tribal names. The English Fever Tree came about (a) because the local people used a bark infusion as a malaria remedy and (b) because early Europeans associated malaria with the tree because mosquitoes live in the water where they grow, so they recognised the association.

Village authorities generally tend to prohibit the cutting of the tree because it grows in groups and the latent belief that it is a malaria cure - which it is not, though who knows maybe it was, because the parasite becomes resistant to treatments as time goes on.

The tree is easily recognised by its green-yellow bark and the fact that it usually grows in groups.

Acacia mearnsii

Acacia mearnsii is the (English) Black wattle, or in Swahili Muwati.

The tree is indigenous to Australia and has a wide natural range - from the hot Queensland in the North to cool Tasmania in the South. In Tanzania it is planted at higher elevation, 1,500 - 2, 500m and is planted on many homesteads.
At Lushoto commercial plantations were established for the extraction of tannin, but the operation seems to be in limbo.

Description: A small tree up to 15 m high. The tree often leans because of the shallow root system. Bark is grey and smooth when young becoming black and fissured with splits and curling with age. The split release brown resinous gum. Leaves are feathery and a dull green, leaflets are small. The stalks are10 - 12 cm long and there is a gland at the base. Flowers are pale yellow, small round heads on branched stalks - sweetly scented. Fruit are pods, either straight or or bent 5 - 10 cm jointed between the seeds. The pods dry to a dull brown colour.

Uses: Very good firewood and charcoal. Poles, posts and tool handles. Good bee forage (pollen), soil conservation, nitrogen fixation, fibre (bark), gum, tannin.

Propagation: There are 50 - 80 000 seeds per kg, they are black and hard and store well.
Germination is >80% if hot water soaked or exposed to fire. Nicking is a sure method but is fiddly because the seed is small.
The tree grows well in nursery pots and performs well at outplanting - responds to super phosphate.

I have grown this species in the NZ nursery as it is used as a chipping crop. However it can become a pest and will even survive amongst P. radiata plantings.
My opinion is that green trees are always good in Tanzania and climate will control its spread. Fuelwood is in short supply so controlling its spread. It does not have thorns.
Thin strips of fresh bark (from young trees) make good cordage - especially in making wattle and daub buildings - drying to be very firm.
The tree grows quickly but tends to be short-lived.
Termites damage the tree from time to time and sometimes there are fungal attacks.
However the tree is useful as cash crop on small scale farms.