Leucaena macrophylla istmensis
Leucaena macrophylla istmensis is a consistently single-stemmed, deciduous tree with a compact narrow crown; it can grow 10 - 12 metres tall[
The tree is occasionally harvested from the wild for local use as a food and source of wood[
Leucaena macrophylla is of little conservation concern. It is widespread and often locally abundant and is present in several protected areas. The plant is classified as 'Least Concern' in the IUCN Red List of Threatened Species(2013)[
Southern N. America - southern Mexico (Oaxaca, Veracruz)
Dry deciduous tropical forest, extending infrequently to mid elevations in foothills in moister oak forest. Most abundant in disturbed areas and secondary vegetation; at elevations up to 400 metres, occasionally up to 1,500 metres[
|Conservation Status||Least Concern
|Other Uses Rating||
Leucaena macrophylla istmensis is a truly tropical form of the species, growing mainly at lower elevations to 400 metres and occasionally to 1,500 metres. It is found in areas of seasonal rainfall, with a mean annual rainfall in the range 700 - 1,500mm and a 4 - 6 month dry season[
Leucaena species generally require a sunny position. They are often found in the wild on poor, shallow and dry soils, usually overlying a calcareous rock. Most of them do not thrive on acid soils. Most species experience a long dry season and are more or less drought tolerant.
The plant is a common element of secondary vegetation and has the potential to spread under open ruderal conditions and become a weed[
A fast-growing tree[
The unripe seedpods are harvested by climbing the trees and lopping the terminal branches or groups of pods, often crudely, with machetes, small knives or cutting poles. Annual pollarding in this way apparently causes only limited damage to the trees which resprout and fruit annually[
This subspecies may have some potential for wood production, although this is limited by its susceptibility to damage by psyllids. In a replicated trial in Honduras, it was found to grow more than twice as fast as subsp. macrophylla and was one of the most productive taxa of all, forming a tall, single-stemmed tree with good diameter growth and high wood biomass production[
The tree is moderately susceptible to damage by psyllids1518].
This species has a symbiotic relationship with certain soil bacteria, these bacteria form nodules on the roots and fix atmospheric nitrogen. Some of this nitrogen is utilized by the growing plant but some can also be used by other plants growing nearby[
Immature seedpods - raw or cooked[
]. Only used very occasionally[
]. The seedpods are 90 - 240mm long and 9 - 26mm wide. There are 2 - 4, occasionally 8, pods produced per flower head[
Seeds - raw or cooked[
]. Often eaten raw as a snack when working in the field, Leucaena seeds are also often used as a garnish on cooked foods or added to stews, mixed with beans and maize tortillas etc. After removal from the pods, the unripe seeds can be dried and stored for later use or ground into a flour and mixed with wheat, corn etc[
]. The seeds are 5 - 6mm wide and 5 - 8mm long, there are around 46,000 seeds/kg[
Young leaves - raw or cooked[
]. Only used very occasionally[
The plant is most abundant in disturbed areas and secondary vegetation where it is fast growing and can dominate early succession, later forming a sub-canopy or understorey tree as the forest cover develops[
]. With the added bonus of fixing atmospheric nitrogen, this sounds like an excellent pioneer species for use in restoring native woodland[
The wood density is below average foe a species of Leucaena, with moderate formation of heartwood. It is locally prized for use in local construction[
The wood is prized as a fuel[
Seed - it has a hard seedcoat and may benefit from scarification before sowing to speed up germination. This can usually be done by pouring a small amount of nearly boiling water on the seeds (being careful not to cook them!) and then soaking them for 12 - 24 hours in warm water. By this time they should have imbibed moisture and swollen - if they have not, then carefully make a nick in the seedcoat (being careful not to damage the embryo) and soak for a further 12 hours before sowing.
Cuttings of semi-ripe wood.
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