Corylus avellana

Corylus avellana in New Zealand is called 'Hazel Nut' and in America it is known as 'Filbert' , which is the way with common names.

We never grew Hazels in Tanzania, but it is a species that could grow in cooler areas. However the reason I want to discuss this species is that it is useful throughout the world and there is a story about it.

The production of hazel nuts was deemed to be a cash crop for people who have such and interest so at the nursery we decided to produce some for sale.
The idea was that roasted hazel nuts, coated in chocolate could be sold at a premium - especially targeting the Japanese market.
The 'demand' was that the nuts should be of a large, even size. So cultivars were produced and one called 'Whiteheart' was deemed to be the best. But the variety did not pollinate well because of the different ripening times of the male and female flowers. Several varieties of pollinators were identified.

We sought guidance from the academics Lincoln University and they could provide cutting material. Corylus avellana is difficult to propagate from cuttings, and were were advised that the cuttings needed to be set into trays at the very earliest instance. The cutting material was from suckers.
The first year we took the cuttings and packed them in water-retaining crystals and set the cutting into trays back at the nursery. Then sat them on heat and under mist. Out of all that, the result was a 10% take. Very expensive plants indeed, especially so because Lincoln University is some 300 km from the nursery and workers needed to be accommodated and fed.

The next few years, we ran a ferry service of filed trays to Lincoln where the cuttings were set and ferried back to the prop house at the nursery - all on the advice of the academics - but all very expensive. The take was not improved by doing this and the cost of production had to be subsidized by other crops. The pollinators were doubly difficult to produce and the cutting material was not available in good amounts.

When I returned from Tanzania the production of Corylus avellana was still lower than demand and the method had not improved. Below is the method I devised that results in a take of around 90%.

But I'm not all that sure that 'Whiteheart' are any better than than other varieties and for sure do not produce a large nut.
I like all nuts and particularly enjoy hazels, but I'm not much of an expert on confectionery. Those Ferrero Rocher chocolates are a testament to marketing with tiny hazel nuts that I would probably reject - and for me they do not rate when compared to chocolate scorched almonds!
So big nuts are not all that important when it comes to confectionery.

Description: A shrub or small deciduous tree up to 3 m. Many branched and often with suckers. Growing tips hairy. Bark is greyish and smooth - growing tips green. Leaves ovate and toothed >10cm but often smaller. Mid green. Make flowers are drooping catkins and female are inconspicuous, small, green. Nuts are in winged husks that open to reveal a hard shelled nut - sometimes in clusters of up to 4.

Uses: Mainly known for nut production, but provides good, low shelter shelter. Hot burning fuelwood and coppices well.

Propagation:

Well the pic isn't all that clear.

Grow stool plants and allow suckers to start. Place over two old car tyres and fill with sawdust [or other media]. It is reasonable to wound the suckers.
After the growing season, remove the tyres and strip away the media. This reveals rooted suckers that can be cut off and potted on.

Otherwise plants are produced by growing the nuts as a seed - I usually crack the hard shell.

Here in New Zealand aphids are attracted to the leaves but do not seem to do harm. However the aphids are able to move on to other plants.
In production orchards the suckers become a problem and are removed when small by using a chemical desiccant.

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.

Acacia albida

Acacia albida is also known botanically as Faidherbia albida and the Swahili name we used was Mgunga, which is known a a strong upright tree.
Mgunga is indigenous to the Middle East and much of Africa - the drier, semi-arid areas, as well as riverine zones in Tanzania where it will grow to an elevation of 1800m. The species generally prefers well drained soils.

Description: Mgunga is one of the tallest of the Acacias - to 30m, with a high rounded crown. It is deciduous often spring to life just before the rains. The branchlets tend to zigzag and are shiny grey. Bark is dull grey, fissured with scales. Thorns are in pairs and often pointing downwards - straight about 2cm. Leaves are compound 3 -8 pairs of pinnae each with 5-25 pairs of grey/green leaflets up to 1cm - rounded and overlapping. Flowers are slender spikes to 14cm, creamy white and attractive to bees, fragrant and appear before foliage. Fruit are distinctive twisted pods, twisted and brown-orange to 25cm long, thick - especially the edges, containing >20 distinctive, hard seeds.

Uses: Timber - local construction, firewood and charcoal, posts, utensils, food flavoring (pods), stock fodder (especially the fallen pods), shade, nitrogen fixation (soil conservation).

Propagation: There are >9000 seeds per kg with 75% viability. Seeds are able to be stored for a long period if kept dry and free from insect attack.
Nicking the seed before direct sowing provides the most even germination. Treating with hot water and soaking for 24 hours is effective but needs to be repeated on seeds that do not swell on the first attempt.

The pods fall to the ground and are much liked by livestock. Of all the indigenous trees that we supplied, Mgunga was the most widely accepted. This is because it is useful and farmers liked the fodder supplied.
In some areas where the tree was unknown, we had to do some talking for the species to be accepted.

After outplanting, the tree grows rapidly - which is a good thing because it does not have to be protected from browsing animals for an extended period.
The species is good to shade crops because it does not compete and enriches the soil.

Cordia africana

Cordia africana, or Mringaringa is a large tree that somehow always looks dry because of the colour of its foliage. Most usually I encountered the species standing alone in farms as a remnant of mixed forest cover. The smell of the flowers drew me to the tree.
Mringaringa was one of the indigenous trees that farmers were prepared to plant.
It is a forest tree and tolerates a wide variety of soils but does not tolerates extremes of drought.

Description: A much branched semi-deciduous tree with a rounded crown growing to about 12 metres. Bark is pale brown and finely grooved but rougher with age. The leaves are large and oval, slightly pointed at the tip and rounded at the base. The underside is covered with soft brown hairs. The leaves feel dry/leathery. Flowers are showy, with white petals and are funnel shaped, scented and attractive to bees.. Fruits are yellowish, 1 cm and in hairy cups. The flesh is sticky and each fruit contains 4-6 seeds.

Uses: Mringaringa is valued for its timber and makes fine furniture, roof shingles and traditional beehives; firewood, medicine (roots & bark), bee forage, shade in coffee plantations, soil conservation and is used as a boundary marker.

Propagation: There are >3000 seeds per Kg with a viability of around 70%. Fruits become ripe August/September. Seed stores for 1 year.
Soak seed in cold water for 12 hours prior to sowing directly into pots and the seedlings are big enough for outplanting after 1 year.
Protected trees establish quickly in the field.

The heartwood is hard and makes very nice bowls and furniture taking polish very well.
The tree does not compete greatly with crops like coffee because the leaves become mulch and as the shuts down, losing its leaves, it provides the opportunity for the soil to rehydrate.

Morus Species

Mulberry is a common tree in parts of Europe and the Middle East and while probably origination from temperate climates, it grows successfully in Tanzania.
There are actually three main species of Morus - alba, indica and nigra. The Swahili name is Mforasdi - usually for the larger fruiting alba and nigra; and the local name Mandela for the smaller fruiting indica. Indica is smaller in leaf and habit as well, but still I will lump these trees together here.

Description: A semi [sometimes] deciduous shrub, much branched <6 metres. Bark is grey and rough with age and resinous gum when cut - young wood has milky sap. Leaves are heart-shaped and toothed - alba having larger leaves and indica < 4cm. Dull green and with hairy underside. Flowers are separate sexes on the same tree - female with long soft hairs. Fruit are compound berries, red and turn black when ripe.

Uses: Fruit, fodder, also fodder for silk worms, fuel, shade, live fence.

Propagation: Easily struck from 8cm cuttings and grows quite fast.

Mandela is not popular because the fruit is small and insignificant but children eat them. However it is a very good tree for fodder as it regrows well, so good as a shelter fence that can be harvested.
The trick to be able to eat the fruit of the Black Mulberry is to beat the birds and monkeys. We had a tree outside our window and cheeky monkeys would regularly rob the pre-ripe fruit!
I was surprised how easily it is to propagate after buying Black Mulberry at home for an expensive price - and they did not perform well at all!
A vet called on me at Makumira wanting me to produce Mulberry trees in large number to start a silk industry - I was able to help him but by focus was not to set individuals up in their own industry. It turned out to be just an idea on his part, but it would be viable in the future.