Melia volkensii in Kenya: current domestication and...
Transcript of Melia volkensii in Kenya: current domestication and...
Melia volkensii in Kenya: current domestication and
improvement programme
Superior melia tree in Mutha, Kitui Photo by J.M. Kimondo
Kimondo, J.M1., Kigwa, B.K.2 and Mbuvi, M.T.E.2 November 2008
1KEFRI, Karura Forest Products Research Centre, PO Box64636 – 00620 Mobil Plaza, Nairobi
2KEFRI, Kitui Regional Research Centre, PO Box 892 – 90200 Kitui
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Melia volkensii in Kenya: current domestication and improvement programme
Introduction
Melia volkensii Gürke (of the family Meliaceae) is a multipurpose tree species endemic in the arid
and semi-arid lands (ASALs) of Eastern Africa. It is generally a fast growing tree, tolerant to dry
conditions and is compatible with most crops, though management through root and crown pruning
are recommended to minimize competition. The growth of Melia volkensii in well-managed plots in
arid and semi arid lands far exceeds those of other indigenous tree species in the same areas.
However, its wide scale planting has been constrained by lack of quality planting material. The
planting of the species has been going on for the last 20 years in small scales on the farms. This has
been mainly from collection of wildings which are then planted directly in the desired place on the
farm or in the nursery where they are managed for some time before planting out. Other planting
has been of seedlings raised in tree nursery from seeds which were generally collected from any
available tree near the nursery with little consideration of the quality of the mother tree. During the
last ten years or so, KEFRI in collaboration with two development partners, namely Japanese
International Cooperation Agency (JICA) through Intensified Social Forestry Project (ISFP) and
Belgian Technical Cooperation (BTC) through Integrated Natural Resources Management of
Ukambani (INRMU), has spearheaded the improvement programme of M. volkensii to enhance the
survival of planted trees on the farms as well as increasing the realised productivity. The programme
involved: (i) selection of phenotypically superior trees in the natural range of the species and on the
farms; (ii) testing of different vegetative propagation techniques to allow multiple replication of
identified mother trees; (iii) testing of appropriate establishment of hedgerows to allow frequent
harvesting of scions or cuttings; and (iv) establishment of clonal seed orchard. Details of each of
these steps are given below.
Species description
Melia volkensii occurs naturally in the semi arid zone of Ethiopia, Somalia, Kenya and Tanzania at
altitudes between 350 and 1700m, in areas with mean annual rainfall of 300-800mm. Though the
species can grow on most soils; sandy, clay and shall stony soils, it prefers sandy soils with good
drainage. The species is common in deciduous bushland in association with acacia-commiphora
vegetation. The tree is deciduous, shedding leaves early in the dry season with new leaves emerging
two to three weeks before the onset of rains. The shedding of leaves is actually triggered by reduced
availability of soil moisture. On cultivated lands therefore, leaves are normally shed late into the dry
season. It grows 6 to 20 metres tall with diameter of around 25 cm though bigger trees are common
in suitable environments.
The species is highly preferred for its high valued timber that is durable and termite resistant in use.
The timber is used for construction and furniture making and locally is one of the main species used
in the construction of log hive because the wood is easy to work. Besides growing fast, the species
coppices readily and is also a valued fodder (twigs, leaves and fruits) especially during the dry season
for goats, cattle and sheep.
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Selection of phenotypically superior trees
The natural stands of Melia volkensii in the wild or natural environment continue to decline
drastically because of population pressure on land for agriculture and human settlement.
Consequently genetically diverse and superior trees required to be conserved in whatever form and
propagated in large populations. In 2004, a country wide survey of Melia was carried out to identify
the location of natural stands and trees where the tree information was captured (appendix 1).
Initially 40 trees were selected in six transects as the base population for the breeding programme.
They were however re-evaluated for their form, growth vigour, apparent resistance to disease and
pest and their branching habits. During this exercise some trees were dropped while new ones were
added to the list. The guiding factor in the selection was identification of trees that could enhance
timber production. Some of the selected trees are as shown:
Table 1 Location and description of some selected plus trees of Melia volkensii
Tree No. 1
Location: Kithima Market, near Assistant chiefs office,
Kithima tree nursery on Isiolo-Meru road
Co-ordinates: 00:21:133 N; 037:33:603 E
Size: 12.0m height, 8 m clear bole, 21.5 cm DBH
Date: 5/12/2005
Class: B
Stressed: Yes, scions to be collected
Status: Secure
Tree No. 1
Tree No. 2:
Location: Maua-Kina Road
Co-ordinates: 00:17:912 N; 038:06:022 E
Size: 8m Ht, 5.5m cler bole and 25.8cm DBH
Date: 5/12/2005
Class: C
Stressed: No, scions collected and grafted
Status: Not Secure, land sold to new owner
Tree No. 2
Tree No. 3:
Location: West of Kina in Rapsu settlement area
Co-ordinates: 00:15:719 N; 038:14:435 E
Size: 9 m Ht, 4,2 m cler bole
Date: 6/12/2005
Class: C
Stressed: Yes, scions to be collected
Status: Secured, acquired from farmer
Tree No. 3
Tree No. 4A
Location: Ishiara-Marimanti Road
Co-ordinates: 00 15 106S; 037 54 531E
Size: 21m Ht, 51cm DBH,
Date: 7/12/2005
Class: B
Stressed: Yes, scions to be collected
Status: Secured from farmer. Tree a replacement of the older nearby tree previously selected
Tree No. 4
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Table 1 (cont)
Tree No. 9
Location: Mbeere, Ishiara, nguthi sub loc.. Ishiara-Marimanti Road
Co-ordinates: 00 27 314S; 037 44 544E
Size:11.5m Ht,
Date: 8/12/2005
Class: C
Stressed: Yes, scions to be collected
Status: Secured from farmer.
Tree No. 9
Tree No.10:
Location: Embu-Ishiara Road
Co-ordinates: 00 27 586S; 037 44 739S
Size: 11m Ht.
Date: 8/12/2005
Class: A
Stressed: Yes, scions to be collected
Status: Secured from farmer.
Tree No. 10
Tree No. 11:
Location: Gatunga-Marimanti area
Co-ordinates: 00 08 609S; 038 04 048E
Size: 10m Ht
Date: 7/12/2005
Class: A
Stressed: Yes, scions to be collected
Status: Secured from farmer for 2 years
Tree No.11
Tree No. 12
Location: Next to Tharaka County Council Offices
Co-ordinates: 00 09 333S; 037 58 239E
Size: 10.5m Ht
Date: 7/12/2005
Class: C
Stressed: Yes, scions to be collected
Status: Secured from farmer for 2 years
Tree No. 12
Tree No. 1 S (Special)
Location: Mwea Riakanau , North of Riakanau Primary school
Co-ordinates:00 49 592S; 037 23 700 E
Size: 1.5 m circumference ie 47.2cm, 13mHt
Date: 8/12/2005
Class: A
Stressed: Yes, scions to be collected
Status: Secured from farmer for 2 years
Tree No 1S
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Table 1 (cont)
Tree No. 10:
Location: Mutha Inyali, Ndakani Loc.
Co-ordinates: 02 581 186N; 046 33 878E
Size: 8m Ht, 19.5cm DBH
Date: 12/12/2005
Class: A
Stressed: Yes, scions to be collected
Status: On-farm, secured from farmer for 2 years
Tree No. 10
Tree No.11:
Location: Mutha Inyali, Justus Munyalis range
Co-ordinates: 02 54 475N; 046 48 083E
Size: 8.5m Ht; 21.5cm DBH
Date: 14/12/2005
Class: B
Stressed: Yes, scions to be collected
Status: Wild, secured from farmer for 2 years
Tree No. 11
Tree No. 12
Location: Mutha Inyali, Justus Munyali range
Co-ordinates: 02 54 442 N; 046 48 089 E
Size: 11m Ht, 25.8cm DBH
Date: 14/12/2005
Class: B
Stressed: Yes, scions to be collected
Status: Wild, secured from farmer for 2 years
Tree No. 12
Tree No. 13
Location: Mutha Inyali, Justus range
Co-ordinates: 02 54 359N, 046 47 302E
Size: 9m Ht; 20.8cm DBH
Date: 14/12/2005
Class: B
Stressed: Yes, scions to be collected
Status: Wild, secured from farmer for 2 years
Tree No. 13
Tree No. 14
Location: Mutha Inyali, Ngaani Loc
Co-ordinates: 0253 608N; 046 44 564 E
Size: 10.5m Ht, 29cm BDH
Date: 14/12/2005
Class: B
Stressed: Yes, scions to be collected
Status: On-farm, secured from farmer for 2 years
Tree No. 14
Tree No. 15
Location: Mutha Inyali Ngaani Location
Co-ordinates: 02 53 956N; 046 44 601E
Size: 11m Ht, 18cm DBH
Date: 14/12/2005
Class: B
Stressed: Yes, scions to be collected
Status: On-farm, secured from farmer for 2 years
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From these selected trees, scions were collected and grafted on melia root stock for the
establishment of clonal seed orchard. Further, the trees had their roots exposed and severed to
encourage them to sprout and later harvesting of the same for planting. However, the sprouting of
the roots took place on the root stump away from the tree and did not develop any root hair. It was
therefore not possible to harvest these sprouts as they did not have immediate roots of their own
that they could depend on. Cuttings were also taken and trials on their rooting undertaken in Kitui
Nursery.
Vegetative propagation techniques
Several methods of mass production of melia planting material have been tested in Kitui and
Muguga. The use of tissue culture manipulation was carried out in laboratories in Muguga where
some encouraging results were realised. In Kibwezi (Fig 1a) and in Kitui (Fig 1b), grafting of scions of
melia on to root stock of melia was carried out and good results obtained. Actually, over 90 percent
success rate was realised and the main limiting factor in the use of the method is the availability of
stock.
Figure 1. Grafted Melia volkensii seedlings in (a) Kibwezi nursery (b) Tiva nursery glass house
While the above procedure meant nursing the grafts in the
nursery and then planting them in the field, it established
that the scions would be grafted directly on to established
saplings in the field and therefore allow the harvesting of
scions within a short period and also avoid the planting
process altogether (Fig 2).
The success of these activities can only be achieved when
the cuttings obtained from the grafted trees can be rooted
en-mass and distributed to potential tree growers.
Currently this is one step that has only achieved marginal
success. While some cuttings have actually rooted (Fig 3a,
b, c), their production in large numbers has remained a
challenge. It is apparent that the rooting success depends
Figure 2. Grafted sapling in Tiva, Kitui on a number of factors that need to be in specific quantum.
Research continues in this area and more need to be done.
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Figure 3. Vigorously growing rooted cuttings at Tiva, Kitui (a) potted seedlings (b) exposed roots (c) two
rooted seedlings at different stages of development
Establishment of melia hedgerows
Hedgerows are normally established to ensure the parent material is kept at the juvenile stage
where irrigation and fertilization can be carried out to ensure vigorous growth. As a result, the hedge
can be harvested more frequently therefore allowing the access of adequate planting material.
Experience so far in the country has revealed
that Eucalyptus grandis should be
established at a spacing of 0.4m by 0.8 m
and between every two rows, a 1 metre
space is left to facilitate harvesting of scions
(Fig 4). There exists no experience in as far as
Melia volkensii is concerned. With due
regard to the broad branching habit of Melia
volkensii, other wider spacing were put in
the trial in November 2006 short rain season.
The other set up was 1m by 1m by 1m and
1m by 1m with a 2m space between every
two rows of seedlings.
Figure 4. Hedge row established at 0.4m by 0.8m and 1m
between pairs of rows of Melia volkensii seedlings
With a wider spacing, the crowding of
branches of neighbouring trees is
reduced as compared to the closely
spaced ones above (Fig 5). However, the
canopy of trees is also intertwined at the
age of two years.
Figure 5. Hedgerows established at 1m by
1m and 1m between rows of Melia volkensii,
at Tiva
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Where an even wider space is
allowed between pairs of seedlings,
the canopies are barely touching at
two years (Fig 6). This implies that
this could be at least the minimum
arrangement to facilitate the growth
of the trees to a reasonable diameter
that could support a large number of
sprouts and at the same time allow
access during harvesting. If larger
diameters of stumps are necessary it
may require that a wider spacing
between pairs of hedgerows are
utilised with the cutting of the trees
Figure 6. Hedgerows established at 1m by 1m and 2m between carried out at later age (Fig 7).
pairs of rows of Melia volkensii at Tiva
During the cutting of the tree to initiate the
sprouting process, cutting must be carried out
above the grafting point (see arrow in the
inset of Fig 7) so that the sprout realised are
those that originated from the scion part and
not the root stock. Actually all sprouts from
the root stock should be removed
immediately they start developing.
Figure 7. Grafted seedlings established at Tiva in
2005 at a spacing of 2m by 4m at age 3.5 years.
Way forward
The current research efforts are geared towards domestication of melia for timber production. As
the species has different uses, it is possible to carry out an improvement programme for other
purposes. The controlling factor in most situations remains the selection of the appropriate mother
trees to provide germplasm that meets the desired product. For instance, selection for drought
resistance requires identification of mother trees in extremely dry environments for collection of
scions. This assumes that there is no dilution effect due to the stock utilised.
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Appendix 1: Tree data collection sheet 1. District……………………………………………………………. 2. Division…………………………………………………………… 3. Location…………………………………………………………… 4. Sub location……………………………………………………….. 5. Transect name…………………………………………………………… 6. Ecological zone…………………………………………………… 7. Altitude…………………………………………………………….. 8. Latitude…………………………………………………………….. 9. Longitude…………………………………………………………… 10. Location of tree (a) on farm ((b) In the wild (c) Others
(specify) 11. Tree No. …………………………………………………………….. 12. Dbh…………………………………………………………………. 13. Height……………………………………………………………….. 14. Clear bole height……………………………………………………. 15. No. of branches …………………………………………………….. 16. Size of branches………………………………………………………. 17. Tree health (1) Die back (2) Diseased (3) Pest 18. Deforms/Defects score………………………………………………….
(1) Excellent (None) (2) Moderate (3) Few (4) Many (5) Extreme
19. Canopy condition:………………………………………… (1) Green with full canopy (2) Fruiting with full canopy (3) moderate canopy
4) Shedding leaves (5) No leaves
20. Bole quality……………………………………………………………………….
1) Spiral grains on bark (2) less spiral (3) No spiral bark (4) Normal plain
bark
22. Benchmark of selected tree: 1) Type ……………………………… 2).Distance……………………………….3). Direction…………………………….
23. If on-farm… Yes/No Name of the farmer…………………….