Species of the Month: Euphorbia tirucalli

This post marks the first in a new series. Each month, we will feature a new species from one of the six biological kingdoms. We will, look at their characteristics and possible duties they can perform for us.

Species of the Month: Euphorbia tirucalli
by Douglas Barnes

Other names that E. tirucalli has gone by include Arthrothamnus tirucalli, Euphorbia media var. Bagshawei, Euphorbia scoparia, Euphorbia media, Euphorbia rhipsaloides, and Euphorbia rhipsalioides.

Euphorbia tirucalli is an African tree that grows in semi-arid, savannah conditions. It is very drought resistant, withstanding long dry seasons. It is salt tolerant and can withstand to just under 5000 ppm arsenic. It will grow from 4 to 15 m tall and at altitudes to 2000 m elevation in hot savannah climates.

It is a coppiceable tree. When coppicing it, cut it at 20 to 30 cm from the ground. It makes good fuel wood with 17,600 kilojoules per kilogram of dry wood; and through pyrolysis, it makes not only charcoal, but also a high octane gasoline substitute. (One to two tonnes of fuel per hectare is what you can expect.) It can also be used as a diesel source.

The timber is useful. And it can be used as a living fence as it is not grazed by animals. Caution must be applied when planting this tree near any human settlement. It must not be in a location where it can contaminate wells or water collection sites as the tree contains co-carcinogens. Latex from the tree can be used as an insecticide and as a fish poison. As an insecticide, it is effective against Colletotrichum capsici, Fusarium pallidoroseum, Botryodiplodia theobromae, Alternaria alternata, Penicillium citrinum, Phomopsis caricae-papayae and Aspergillus niger and against the nematodes Hoplolaimus indicus, Helicotylenchus indicus and Tylenchus filiformis. The latex can also be used as a glue.

It has medicinal properties, though one would use caution obviously. The young twigs from the tree are roasted (presumably breaking down the poisons) and chewed to sooth sore throats. A poultice made from the greenwood is used to treat broken bones. Despite the toxins and co-carcinogens it contains, some of its compounds have been used to treat cancers.