It thrives in altitudes below 500 m and prefers climates with rainfall between 600 - 3,000 mm annually. It can withstand rainfalls as low as 250 mm and is able to tolerate some salinity and waterlogging. It requires full sun and grows best in deeper, well-drained soils. It does not grow well on acidic soils and is vulnerable to heavy frosts.
Leucaena
Leucaena, also known as the "Pioneers" plant, is a fast-growing tree that can reach heights of up to 20 meters. It has three distinct forms: a low shrub with abundant foliage, a tall forest tree with little seed production, and a medium-sized tree with close-to-ground branching. Leucaena is commonly used as a nurse tree in tropical agriculture, providing shade and a nitrogen-rich humus source. It is also a valuable stock feed due to its high protein content and can be used for timber, energy production, and various culinary purposes.
Eucaena leucocephala
Mexico
Other Relevant Information: - Leucaena is known for its nitrogen-fixing ability, which helps improve soil fertility. - The plant has been used for erosion control due to its extensive root system. - Leucaena is used as a shade tree in agroforestry systems, providing protection for crops. - It has been used in traditional medicine for various purposes, including treating skin conditions and gastrointestinal disorders. - The plant is also valued for its ornamental qualities, with its bright, showy flowers. - Leucaena has been introduced to many countries around the world and has become naturalized in some regions. - The wood of the leucaena tree is resistant to termites and decay, making it suitable for construction purposes. - The plant has been studied for its potential as a biofuel crop, as it is fast-growing and produces significant biomass.
It grows best in deeper, well-drained soils and does not grow well on acidic soils.
The most commercially exploited of the genus, it takes three distinct forms. The common form is a low shrub rarely exceeding 5 m which produces abundant foliage, flower and seed. The giant or Salvador type is a tall forest tree reaching over 20 m which produces little seed but the fastest bio - mass rate (varieties include: Hawaiian giants - K8, K28, El Salvador - K67). Peru type is a medium sized tree to 10 m which branches close to the ground and produces an abundance of foliage and seed.
It is fast growing (often claimed to be the fastest growing tree in the tropics) and is usually an evergreen, although it can shed its leaves in frost, storm and drought. It can withstand rainfalls as low as 250 mm but does best in rainfalls between 600 - 3,000 mm annually. It gives best growth at altitudes less than 500 m. It is able to withstand some salinity and waterlogging, although best results are achieved in deeper, well drained soils. It has been successfully grown right down to the high water mark in exposed coastal situations. It requires full sun. The plant can be killed by heavy frosts and does not grow well on acidic soils.
In the tropics, the giant form of the tree is used extensively as the classic nurse tree to crops such as cacao. The tree provides a shaded environment and the leaf drop from the leucaena is a good humus source which is rich in nitrogen. Alley cropping between rows of leucaena is used to grow crops such as corn, tobacco, yams and rice. The rows of leucaena are kept pruned so as not to rob the crops of light. Leucaena is also used to stabilise ground subject to shifting agriculture. Once a leucaena system is in place, agriculture can remain, taking the pressure off otherwise at risk forest.
The young leaves, pods and flower buds are eaten raw, steamed, in soups and stews, with rice, or mixed with chillies and spices. Unripe seeds, mixed with grated coconut and fish or meat are cooked wrapped in banana leaves. The mature, but not dried out seeds, are eaten raw or cooked. Dried seeds are made into tempeh type ferments, are also ground as a coffee substitute and are eaten as sprouts. Mimosine contents would have to be explored before these could be taken seriously as staple foods.
Leucaena is a high protein stock feed. Some of the highest stock weight gains ever recorded are attributed to leucaena. Leucaena can recover from browsing and be ready for further browsing in just two weeks. The ideal leucaena forage system incorporates a range of other species including grasses. Leucaena fed alone will result in mimosine toxicity. Ideally, leucaena should only form about 30% of the long term diet. Sheep fed for a few days on an exclusive leucaena diet suffer a fracture in their wool which makes it possible to shear them by simply pulling the wool away.
The giant types provide significant timber in short rotation. They are thin barked with a yellow - white sapwood and a yellow to reddish - brown heartwood. It has similar density and strengths (tensile, compressive, and shear) to oak, ash, birch and sugar maple. It is fine textured and easily worked. In India, a small demonstration house has been built complete with furniture and fittings from 2 year old leucaena trees. It is one of the best tropical hardwoods for paper pulp and rayon manufacture and is also used in chipboard production. The round logs can be used as fence posts, bean poles, girders, floor joists and rafters.
Leucaena is a primary energy source in many tropical communities. Plantations are harvested in a three to five year rotation. Wood from young trees has a heating value of 4,600 kcal per kg. Charcoal from leucaena has a heating value of about 7000 kcal per kg.
Leucaena stands of 10 m or more in width can suppress the spread of fire. The plants soon recover and regenerate after fire.