Grevillea robusta

Grevillea robusta : Silky Oak - Mgrivea
Description : An Australian tree. A large, straight tree (20m) with fern-like leaves with underside silver-grey.
Uses : Timber, firewood/charcoal, fodder, nectar.
Propagation : From seed, they are papery tin discs. Difficult to collect because once the pods are ripe, the seed falls. There are about 80 000 viable seeds per kg. Germination of fresh seed is good >50%. Unless refrigerated, seed remains viable for only 3 months. I have gathered fallen seed - not bad if ground is bare. Small wildlings <80mm>
Management : Newly established seedling a vulnerable to termite attack. Pruned trees give good timber and pollarding is often carried out to provide light for crops beneath and when taking fodder in lean times.
Grevillea is a strong, versatile timber but it is a pity it is susceptible to termite attack. Chemical treatment may be helpful and waste engine oil is painted on to it for protection. This spoils the grain which is actually beautiful.
To control termite when first planted out, I mixed 1kg of chillies in 20 litres of water. (I could get powder from Incofin who produce seed and the powder is a residue. Don't breathe the powder in - it more than clears the sinuses!) Add to the mix a generous portion of Neem oil and the job is done! Chillies have this property of being hot and transfers through the plant systemically. You just water the plant with the mixture.
This was the most requested plant in the nursery! Why? Money can be made from it!
Termites cover their activities by packing mud over their excavations and you don't notice the damage until you check it and I have found all the wood has been replaced by mud! I have repaired schools so damaged.
Losses of Grevillea plantings could be man-made so I had to carry out appropriate education. Children picked the young branches to use as toothbrushes! To them it was a cheap and effective method of dental care. At all schools, a duty class arrives 1/2 an hour early to clean the school and sweep the yard. With no brooms available, tree branches are used. This can decimate school plantings.
I was common to see young men sawing timber in the old fashioned pits that actually produce good quality timber. Of late chainsaws have arrived and make a surprisingly good job of doing something they were not designed to do. But it wastes a lot of wood.
The wood is versatile - I saw a guy using a panga (bush knife) to make scallops in school desks - that is skillful!
We had some large trees in out yard and the monkeys used to feed on the flowers that were full of nectar. They had their aerial path and checked out the mango tree, the Albizzia and Newtonia trees as well as the Avocado. Monkeys are wasteful and eat young shoots unripe fruit and insects living there. These were Sykes Monkeys and playful they were!

Sowing seed.

One of the changes I suggested for village nurseries, and what I did in our own central nursery as to introduce direct seeding into the pots.

It is usual to sow seed into a seed bed, then prick out the seedlings into the pot. But this has a big disadvantage in Tanzania. Most areas suffer from adequate supplies of water, and when seedlings are pricked out, they needed to be 'watered in' and in the first few days require regular watering. [Dampening off is not such a problem but does occur]

Direct sowing allows at least some flexibility, I research what the likely seed viability is and sow accordingly - eg. if viability is 30%, I sow 3 seeds per pot. Sometimes it may be necessary to thin them out - that can be done when weeding, but also if conditions and luck are with you, the seedling can be pricked out into pots that have not germinated; give them a chance!

The pots are cut from rolls of flat polythene tubing (black if possible). Instead of cutting one at a time, whittle down a stick so the circumference (or perimeter, if it is rectangular) equates to around 100mm. Wrap the polythene tubing around it - tightly - about ten times, then cut across it. You will have ten pot +- 100mm ready to be filled. The bottom 1/4 needs to be tightly packed with soil/mix, so it does not fall out the bottom; but you are not making bricks, and seedlings will not grow in bricks!

I drew this diagram to help, but the labelling is too small.

Note that there is no bottom to the pot. Nearly fill the pot with soil/mix and make a depression with your thumb. The seed(s) is placed in the depression and covered with sawdust less than 1 cm.

Cover the sawdust with marram (volcanic ash) or pebbles.

The sawdust holds moisture and does not get too hot. The marram hold the sawdust in place while watering or if windy; it also helps to retain the moisture.

I used to go to portable sawmills to collect sawdust and there were always young men eager to fill the truck for 500/- or so. They became used to me and often asked me what I did with the sawdust.

'I use it in my tree nursery." I told them.

Well soon sawdust became in short supply - people equated my need for it with fertilizer! Applying to their crops. Actually, while it rots down, it robs nitrogen, but release it later. Urea would have been better for them.

I guess any of my vehicles could carry half a cubic metre of marram - that would last perhaps a month or six weeks. There was a huge deposit of it at Engarora and lorries used to buy it there. Again the young men would fill my truck and banter with me about paying more, helping them financially or giving them a job. Have no doubt though, their work war hard and dangerous; and rough as they were, they earned their money!

Roots will soon grow into the soil below the pots, so they must be cut regularly - this is a chore. But has to be done.

I sat my pots on polythene sheeting. As good is a frame of chicken wire (off the ground and the air prune).

I wanted to carry out my operation in the same way I expected the village nurseries to operate, so I hand watered using a 15 litre watering can. Every night taking about an hour. Sometime I watered in the morning as well.

I found I could look village people in the eye and say that nursery work is hard, but rewarding work!

Dovyalis caffra

Dovyalis caffra - Kei Apple - Mchongoma

Description: A thorny tree/shrub tolerating dry conditions once established. The fruits are small yellow apples.

Uses: Used as a secure boundary hedge. Fruits are edible but seldom used.

Propagation: Remove seed from very ripe fruit, wash and dry. Sow fresh as seed does not store well. there are 30 000 viable seeds per kilogram. Germination takes place in 18 - 22 days.

Management: After planting out, tend to keep weeds away and water at least once a week. Trimming is the easiest way to make a tidy hedge.

As with most seed I looked for a boy or someone to collect the fruit for me - I could easily pick it myself but this provides income for someone. The prepared seed is saleable too.

Seedlings of Mchongoma are sought after because they make a secure hedge and many people try to make an income from selling seedlings. Like all nursery production, there are always challenges and the biggest challenge is actually getting paid! There are always hard times in Tanzania and especially in the rural villages, there may be a drought and nobody has the cash to buy seedlings.

The hedge is even more secure if it is plaited instead of being trimmed; but those thorns a large and sharp - the branches are prodded into shape using small forked sticks.

Mwarubaini

In Kiswahili the name of most trees start with 'M' which immediately defines the name as being that of a tree.

There are two Mwarubaini -

• kamili: meaning exact/perfect.
• nusu: meaning half.

Despite the two trees looking alike, they are different species and many people do not understand the difference.

The name indicates that the tree has 40 uses

• Kamili is Azadirachta indica - Neem. This tree has perhaps 60 uses and is an important medicinal tree.
• Nusu is Melia azedarach - Bead Tree. This tree is generally piosonous despite the fact that it is used medicinally. The leaves are a good insecticide.

The trees look alike and the flowers are alike, but see the trees side by side and you can see the difference. Even the fruits look alike. The way to tell which tree is which is by the seed. Strip off the flesh of the fruit and the seed of the Kamili is smooth; the seed of the Nusu is ribbed with a hole at each end making it handy to make a bead out of it. The coat of this 'seed' is very hard and actually there are five small, black seeds inside.

I was demonstrating this with actual fruit to a group at the village of Nadasoito and while I was talking to individuals, I missed the routine nawa, washing hands before eating. I ate a cob of roasted maize. That evening I was violently sick! Poison from the Nusu (Melia) remained on my fingers and I ingested it.

The scary thing is that around the Arusha region, it is just too cold for Kamili to grow well, but Nusu thrives. People think it is Kamili and use it for treatment of several ailments including malaria! Other know that Nusu is piosonous and use it to purge themselves if they think they need a 'good cleanout'. Others try to abort unwanted pregnancy using Nusu - it does not cause abortion - but I do not like to contemplate what it might do for that small child after birth.

A good use for Nusu leaves is to put into books to stop silverfish, and into bags of Maize/Beans to stop insect attack.

I will detail these two species later.

Starting

Working under trees

I decided to do this separate blog from the tree nursery perspective and especially in Tanzania. I hope it becomes a tool to refer to so people do not have to go through the learning process that I did. Having said that, the learning process can be most rewarding. The other rewarding thing is learning to associate with the local people - wherever you are!

On my other blog Footsteps NZ - TZ I have put the old poster and some of the information about our seminars.