Erythrina amasisa Spruce

Erythrina poeppigiana is a large tree, growing to 35 m in height and 2 m in diameter. The crown is moderately spreading and the bole tends to be branchless below 10-20 m. Bark is greyish brown or grey, with thornlike protuberances. Leaves are alternate, trifoliolate; folioles rhomboid-oval or oval, 15-25 cm long, generally larger in saplings than in big trees; glandular stipules below the paired lateral folioles, large and cup shaped. Flowers caducous, orange or reddish, produced in racemes; racemes 10-20 cm long; petals 5; stamens 10; anthers brown; upper petal wide and open. Pods 12-25 cm long, with several seeds, falcate, slightly depressed between seeds, long stalked, pointed at both ends; seeds brown, about 2 cm long, slightly curved, 1-2 cm long, weighing about 183 g each. Erythrina comes from the Greek word ‘eruthros’-red, alluding to the showy red flowers of the Erythrina species.

Perching passerine birds pollinate E. poeppigiana. In Costa Rica, the phenology of unpruned E. poeppigiana shifts from evergreen to deciduous along a rainfall gradient from the humid lowlands to the subhumid mountains. The leafless period is quite short and is possibly caused by flowering rather than drought. A visible reduction of foliage during flowering also occurs under humid conditions.

Tolerates low soil fertility and relatively high acidity (down to pH 4.3). However, tolerance varies by genotype.

E. poeppigiana is native to humid and subhumid tropical lowlands, such as the riverine and upland forests of the Amazon and Orinoco Basins, but cultivated and naturalized trees are now found at elevations up to 2000 m.

Introduced to Central America and a number of Caribbean Islands in the 19th century, E. poeppigiana is widely naturalized in some areas such as Costa Rica and Trinidad and Tobago.

Vegetative propagation methods used include air-layering, where the roots appear after about 6 weeks. The leaves must be removed before planting and the top cut made at an angle of 45 degrees and sealed with paraffin. Cuttings should be long (over 1.5 m). Stakes from lower and middle sections of 1- and 2-year-old branches give best results. Cuttings are planted at a depth of 30 cm. Inoculation of seeds or cuttings with Bradyrhizobium bacteria is not generally required in areas where E. poeppigiana is native or naturalized. However, inoculation is recommended when introducing the species to new areas.

E. poeppigiana can be planted at a spacing of 8 x 8 m for unpruned trees and 6 x 6 m for pruned trees. The seedling survival is generally good, but weed control may be necessary during the 1st year to enhance growth. A formation pruning is recommended about 4-6 months after planting to remove the lowest branches. Normal pruning management may start 9-12 months after planting. Tall crops should not be associated with E. poeppigiana before the 1st complete pruning, but low crops may be planted at the time of formation pruning. In coffee plantations in Costa Rica, E. poeppigiana is usually pruned completely and lopped to a height of 2-3 m twice a year to promote coffee flowering and ripening of berries. Due to the slow recovery of carbohydrate reserves, pruning E. poeppigiana more often than twice a year risks the debilitation and turnover of trees within a few years. Pruning trees periodically will prevent complete leaf fall, and pruning trees once a year is enough to impede flowering.

Adult June beetles (Phyllophaga menetriesi, Coleoptera: Scarabaeidae) feed on young leaves of E. poeppigiana. Because June beetles lay eggs close to foraging areas, the root-eating larvae are a potential risk for associated crops. Only minor damage has been observed in maize alley cropped with E. poeppigiana.

Seed storage behaviour is orthodox. The seeds may be stored for several years in tightly closed containers in a cool, dry place (about 5 deg. C, 30-40% r.h.). There are about 4500 seeds/kg. Immersing the seeds in water at room temperature for 24 hours enhances germination. The germination rate is about 70%.

Shade or shelter: Planted as a shade tree in cacao plantations in the humid tropics, E. poeppigiana conserves soil and contributes to high and sustainable cacao yields. Nitrogen fixing: E. poeppigiana nodulates abundantly with nitrogen-fixing bacteria of the genus Bradyrhizobium. Peak values exceeding 1000 kg/ha of nodules have been reported for unpruned cacao shade trees. Soil improver: The green leaves of E. poeppigiana contain 4.1-4.9% nitrogen, which makes it an excellent species for green manure production. Production of nitrogen-rich litter is abundant, and the nitrogen supply in litter fall exceeds several times the export of nitrogen in the cacao harvest. The nitrogen supplied through pruning residues left on the ground fulfils recommended nitrogen application rates. Intercropping: For alley cropping, E. poeppigiana should be planted in dense hedgerows (1-2 m between trees), with wide alleys (6-8 m) between tree rows. High and sustainable bean yield in the alley-cropping system has been observed. In Costa Rica, E. poeppigiana alley cropping has sustained 2 maize crops per year over 8 years without fertilization. Coffee and cacao may also be planted together with the trees.

Fodder: The green leaves of E. poeppigiana have a good nutritive value (20-22% of dry matter), are high in crude protein (27-34%), and have a good range of in-vitro digestibility (49-57%). However, due to their high cell wall content (55-58%), they should be supplemented with energy sources, such as tropical grasses, which are readily degradable in the rumen. The presence of potentially toxic alkaloids in the leaves of E. poeppigiana has not affected the health of cattle or goats, but feeding leaves to non-ruminants may be risky. Fuel: Although the wood is light, with low calorific value, it is sometimes used as a firewood.