Leucaena diversifolia


Scientific name

Leucaena diversifolia (Schltdl.) Benth.

Synonyms

Acacia diversifolia Schltdl.
Leucaena brachycarpa Urban
Leucaena laxifolia Urban
Leucaena pulverulenta (Schldl.) Benth. var. brachycarpa (Urban) Zárate

Family/tribe

Family: Fabaceae (alt. Leguminosae) subfamily: Mimosoideae tribe: Mimoseae. Also placed in: Mimosaceae.

Common names

diversifolia, leucaena, red leucaena, wild tamarind (English);  ipil-ipil (Filipino);  leucaena petit feuille (French);  lamtoro (Indonesian);  guaje (Spanish);  guajillo (Mexico):  wild tamarind (Jamaica, as for L. leucocephala )

Morphological description

Small to medium sized tree (5-20m) with an open spreading crown rising from a single stem 20-50 cm in diameter.  Bipinnate leaves with 16-24 (occasionally 14-28) pairs of pinnae;  48-58 pairs of leaflets per pinnae, 4.5-7 mm long, linear-oblong in shape, hairless except at the margins;  petioles (pinnular rachis) covered with white hairs.  Petiole gland highly variable in size and shape.
Flower heads variable in colour from pale pink to bright pink, occasionally bright scarlet, 11-15 mm in diameter, in groups of 1-5, developing in the leaf axils of actively growing, indeterminate shoots.
Pods narrowly linear-oblong and flat, 10-13 cm long x 13-16 mm wide;  1-6 pods per flower head containing 6-20 seeds.  Pods papery in texture, dark brown or reddish-brown, sometimes lustrous, may be hairless or covered in dense velvety hairs, opening along both sides.  Small seeds 4.3-5.5 mm wide, 2.7-3.4 mm long.  It is one of the smaller seeded leucaenas with 60,000-80,000 seeds/kg.

Distribution

Native to:
Restricted to the non-seasonal, wet (>1,200 mm annual rainfall ), mid-elevation, northern and eastern slopes of the Sierra Madre Oriental in central and southeastern Mexico.  Generally frost-free, sub-montane environments with high cloud cover.

Uses/applications

Used as a shade over coffee in frost-free highland tropical locations.  Villagers in Mexico and Guatemala occasionally consume the pods.  Has been extensively evaluated in agronomic and to a lesser extent animal production trials.  Used in hybridisation programs with L. leucocephala to improve the psyllid insect resistance and acid-soil tolerance of the latter species, and to produce timber cultivars.

Ecology

Soil requirements

In the native range, grows in deep, free-draining soils of mildly acid reaction (pH 5.5-6.5).

Moisture

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Native to 1,500-3,500 mm annual rainfall , high altitude regions with very short dry seasons (0-3 months).

Temperature

Grows at 30-1,500 m asl in frost-free climates with average annual temperatures from 18-22ºC.  Young seedlings can be killed by moderate frosts.

Light

Native to regions with constant cloud cover and is therefore likely to possess some shade tolerance.

Reproductive development

Flowers predominantly over early summer (May to June in Mexico) but flowering can occur year-round, with the exception of mid-winter.  Fruits predominantly over autumn and winter (August to February in Mexico) but fruiting can occur year-round.

Defoliation

Most accessions were tolerant of regular cutting in forage production trials in Hawaii, Florida, Australia and southeast Asia.  L. diversifolia CPI 33820 was tolerant of regular grazing by cattle in northern Queensland, Australia.

Fire

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Mature plants are tolerant of moderate intensity fires, regrowing readily from burnt stumps or branches.

Agronomy

Establishment

Similarly slow (or slower) to establish as L. leucocephala cv. Cunningham in trials throughout Australia and southeast Asia.
For best results plant on deep, well drained soils with a pH above 5.0 and maintain a weed-free area of at least 2 m either side of the establishing plants.  Seed must be scarified to break the impermeable testa.  Mechanical scarification, using coarse sandpaper (for small seed lots) or abrasive lined rotating drum scarifiers, is preferred.  Previously, hot-water treatment was recommended but resulted in highly variable outcomes including reduced vigour and/or viability and uneven germination. Specific rhizobium is required (eg. CB 3060, TAL 1145, LDK4).
Complete cultivation is recommended in extensive plantings.  Seeding rates of 1.5-3.0 kg/ha are planted into rows 4-9 m apart.  Post-plant herbicides such as bentazone and imazethapyr can be used to control weed seedlings in the rows.  Rolling cultivators can be used to control very young weed seedlings and break soils crusts before or after emergence of leucaena seedlings.
Small areas can be planted using seed or seedlings.  Seedlings are normally raised in poly bags for plug planting at 3-4 months old.  Seedlings can also be raised in beds and removed for planting as bare-rooted seedlings if topped and tailed.

Fertiliser

Normally not fertilised.  Starter N and P may be used when establishing into depleted soils, and lime may be required on soils with pH <5.0.  Replacement fertiliser is required in highly productive cut-and-carry systems.

Compatibility (with other species)

The low palatability of L. diversifolia under grazing may result in dense canopies and consequently, low productivity of understorey grasses.

Companion species

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Grasses:  Has been grown in combination with signal grass (Brachiaria decumbens ) in humid-tropical northern Australia.

Pests and diseases

Accessions range in susceptibility to the psyllid insect from moderately resistant (eg. K778 and K784) to highly susceptible (K156 and OFI 106/94). 
A range of pathogenic fungi and other insects occasionally attack L. diversifolia .  Newly emerged nursery and field-grown seedlings are susceptible to damping-off diseases caused by the fungal species, Pythium or Rhizoctonia
The soft scale (Cocus longulus) attacks the tall stems causing a reduction in productivity.  The associated sooty mould that develops on the sugary exudates from the scale can cover the stems and temporarily kill under-storey grasses.  Soft scale is generally an infrequent pest, with populations rarely building to cause economic damage.
A range of soil insects such as earwigs, scarab beetles, termites and cut worms can cause serious damage to emerging seedlings and should be controlled using insecticide baits.
Seed production can be reduced by the flower-eating larvae of the moth Ithome lassula , and by four species of seed-eating bruchid beetles of the Acanthoscelides genus.

Ability to spread

Has potential to colonise bare ground from seed but is unlikely to spread under grazing.

Weed potential

Likely to be similar to L. leucocephala , being self-compatible and flowering and fruiting over an extended season.  Has significant potential to become a weed of disturbed areas, but no records of current weediness were cited.

Feeding value

Nutritive value

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Crude protein concentrations range from 25-32% of DM.  In vitro DM digestibility ranges from 56-61% of DM, but in vivo DM digestibility is low due to high concentrations of condensed tannins (6-19% of DM).  The high CT concentrations preclude the feeding of L. diversifolia to monogastrics and limit its value as a protein supplement for ruminants.

Palatability/acceptability

CPI 33820 was reported to be of similar low palatability as L. pallida and L. trichandra in long-term grazing trials.  Well accepted by sheep and cattle in short-term grazing and cafeteria trials.

Toxicity

Contains low concentrations (approx. 2% of DM) of the toxic amino acid, mimosine.  Also contains condensed tannins (6-19% of DM).

Production potential

Dry matter

L. diversifolia accessions are of low to moderate productivity in most tropical locations.  The species is generally adapted to sub-tropical and highland tropical regions with medium to high rainfall (>1,200 mm/year), where forage yields of 3-4 t/ha can be produced.

Animal production

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There are few reports of animal production from L. diversifolia .  In humid-tropical northern Australia, L. diversifolia CPI 33820 supported liveweight gains in steers of 0.53 kg/head/day over a 6-month period, which exceeded that from the sabi grass (Urochloa mosambicensis cv. Nixon) control treatment (0.38 kg/head/day).

Genetics/breeding

L. diversifolia is a self-compatible tetraploid with a chromosome number of 2n = 4x = 104.  Probably an allotetraploid with L. pulverulenta as the maternal parent.  L. diversifolia hybridises well with other tetraploid species but less well with diploid species of Leucaena.

Seed production

Produces large amounts of seed over an extended season under suitable rainfall conditions.  Seed orchards were successfully developed in Hawaii and northern Australia, but no estimates of seed yields are given.

Herbicide effects

Can be controlled by basal bark application of herbicides containing 120 g/L picloram and 240 g/L triclopyr mixed with diesel.
Application of glyphosate to regrowth following slashing will kill trees although repeat applications may be necessary.

Strengths

  • Possesses some low temperature adaptation.
  • Some accessions are psyllid resistant.
  • May possess modest tolerance of acid-soils.
  • Tolerant of regular coppicing .
  • Has potential as a medium density pole timber or fuelwood.

Limitations

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  • Low palatability to grazing ruminants.
  • Relatively low nutritive quality, supporting only moderate liveweight gains.
  • Poorly adapted to dry and/or hot environments, cf. L. leucocephala .

Other comments

Previously referred to in University of Hawaii and other information as "tetraploid " or "4n L. diversifolia ".

Selected references

Hughes, C.E. (1998) Leucaena, A genetic resources handbook. Oxford University Press, UK.
Jones, R.J., Galgal, K.K., Castillo, A.C., Palmer, B., Deocareza, A. and Bolam, M. (1998) Animal production from five species of Leucaena. In: Shelton, H.M., Gutteridge, R.C., Mullen, B.F. and Bray, R.A. (eds) Leucaena - adaptation, quality and farming systems. pp. 247-252. (ACIAR, Canberra, Australia).
Mullen, B.F., Shelton, H.M., Gutteridge, R.C. and Basford, K.E. (2003) Agronomic evaluation of Leucaena. Part 1. Adaptation to environmental challenges in multi-environment trials. Agroforestry Systems, 58, 77-92.
Shelton, H.M., Gutteridge, R.C., Mullen, B.F. and Bray, R.A. (1998) (eds) Leucaena - adaptation, quality and farming systems. ACIAR, Canberra, Australia.

Internet links

Cultivars

Cultivars

Country/date released

Details

No cultivars of L. diversifolia have been formally released.          

Promising accessions

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Promising accessions

Country

Details

K156 Hawaii (not formally released). No longer used, K156 was selected by the University of Hawaii for its psyllid resistance and ability to grow productively at relatively high altitudes in Hawaii.  L. diversifolia accessions of superior psyllid resistance and low temperature adaptation have subsequently been identified.  K156 was incorporated into a range of early KX3 hybrids as the maternal parent.
CPI 33820 Australia (on pre-release 1994, never released). Selected by R. Bray, CSIRO for its psyllid resistance and yield potential and was put on pre-release pending the outcomes of animal production trials.  Its poor ability to support high liveweight gains precluded further accession development.
K778, K784 and K802 Hawaii and Australia. Accessions K778, K784 and K802 were collected by J. Brewbaker et al. at an altitude of 1,200 m asl in Veracruz, Mexico and these appeared to be well adapted to lower temperatures in Hawaii and at Brisbane, Australia.  They also possessed considerable psyllid resistance and were very productive in fuelwood production trials.
K785 Hawaii. Similar to the above accessions, K785 has been used in the development of a recent KX3 hybrid accession adapted to upland tropical environments.