Better Globe Forestry

Silvicultural management on mukau and Jatropha curcas

The ideal silvicultural management schedule of mukau is a work in progress. Information about spacing, pruning and thinning in monoculture plantations is gradually merging into a coherent management table. Several crude models have been established, such as the one below:

Management schedule for mukau in semi arid to arid areas

Year Item Remarks
1 Clearing, ripping and harrowing By bulldozer, ripping down to 80cm, and tractor
1 Pitting 20x20x20cm, 400 pits
1 Planting 400 seedlings + 20% beating up (5x5m planting distance)
1 Fertilising 50g fertiliser per seedling
1 Maintenance Ploughing or harrowing, 15-20cm deep
1 Spraying with herbicide Close to the trees where the harrowing did not reach
1 1st pruning Up to 1m, at 4 months (secateurs and by hand)
1 2nd pruning At 6 months (pruning saw, secateurs and by hand)
1
3rd pruning At 8 months (pruning saw, secateurs and by hand)
2
Maintenance Ploughing or harrowing, 15-20cm deep, 4 times
2
Fertilising 200g fertiliser per tree, mixed with superficial soil layer
2
Spraying with herbicide Close to the trees where the harrowing did not reach
2
4th pruning With ladder, selectively removing branches
2
5th pruning With ladder, selectively removing branches
3 6th pruning
With ladder, selectively removing branches
3
Maintenance Ploughing or harrowing, 15-20cm deep, 4 times
4
7th pruning Up to 5m
4
Maintenance Ploughing or harrowing, 15-20cm deep, 4 times
5-7
Maintenance Ploughing or harrowing, 15-20cm deep, 2 times
8 Thinning 1/4 or 100 trees, DBH 25 cm, 5 m
volume/ha (m3) 17.17
8-19 Maintenance Ploughing or harrowing, 15-20cm deep, 2 times
20 Felling 300 trees, DBH 50cm, 5m
volume/ha (m3) 206.06
TOTAL VOLUME/HA 223.23
MAI – mean annual increment  (m3/ha/y) 11.16

Serious work still needs to be done on optimisation of pruning schedules, while the concept of a single thinning can be challenged, as superior genetic material is not yet available. The number of thinnings is related to planting distance, as thinnings are only a means to eliminate inferior material and favour better quality trees.

A silvicultural treatment trial has been established in Kiambere (June 2009) for Jatropha curcas, concentrating on the interaction of different levels of fertilising (0, 50 and 100g of Mavuno) with two different spacings (2mx2m and 3mx3m) and different pruning treatments. The trial was done in cooperation with Endelevu Energy and ICRAF.

 
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