Piptadenia buchananii Baker

Newtonia buchananii is a tall deciduous tree 10-40 m high, with a rather flat crown. The tree trunk is often short but can be extremely high in forest valleys, with strongly fluted buttresses. Bark is smooth and light grey. Branchlets with rust-brown hairs. Leaves bipinnate, leaflets numerous (24-)38-67 pairs, linear or falcate 2-9 mm long, tiny and light green when young. Leaf rachis with a stipitate tiny gland between each pinna-pair. Inflorescences in erect cream spikes fading to brown, 3-18 cm long. Flowers sessile or nearly so, anthers with an apical gland that soon falls off, ovary densely pilose outside. Pods brown, 1.3-2.5 cm, thin 15-30 cm long, splitting open on one side. Seeds lying longitudinally in the pod, seeds flat, distinctive red-brown, to 4-7 cm long, 1-2 cm wide, surrounded by a membranous wing. The generic and specific epithets are honorary for Sir Isaac Newton, the famous English scientist, and Buchanan, a botanical collector and Vice Consul in Malawi from 1877-1890.

N. buchananii is common in lowland and upland rain forest, usually near streams, ground water, or as a component of riverine, mist or swamp forest.

The main propagation methods are direct seeding, root suckers and wildlings.

N. buchananii is a fairly fast growing tree once established, but needs care during the establishment phase.

Germination percentage rates are up to 90% in 20-30 days. There are 3 000-13 000 seeds/ kg. No pretreatment is necessary. However the seeds remain viable for only a few weeks at room temperature storage. Pods should be collected from the tree crown immediately they turn brown, then dried before seed extraction. Direct sowing does not appear to be a suitable method for regenerating N. buchananii: survival (26%) and growth were slow in trials at Amani, Tanzania.

Erosion control: The tree protects riverine soil from erosion. Shade or shelter: The tree’s crown gives light shade. Soil improver: The leaves are used in agriculture as mulch. Ornamental: N. buchananii has a graceful form, flat topped and tall, making an ideal choice for gardens, parks and homes. Boundary or barrier or support: Poles are used for fencing. Intercropping: N. buchananii’s crown gives light shade, which may not injuriously affect other crops in agroforestry systems.

Fodder: The foliage and pods are eaten by livestock and can be gathered as fodder. Apiculture: N. buchananii is a good source of nectar and pollen for bees. Fuel: A good source of quality firewood. Timber: The brown to red-brown hardwood is durable in water and thus a favourite for boat/ canoe building. Poles from the tree are used in house construction. Gum or resin: A yellow-brown resin exudes from the bark when cut.