pierre laszlo

Terminalia catappa (Combretaceae)

Terminalia catappa (Combretaceae).

This handsome tree is commonly known under names such as tropical almond tree or Indian almond tree. It grows to 35 m (75-115 ft) tall, with an upright, symmetrical crown and horizontal branches, with a spread of 20 m (50-70 ft).
The genus owes its name to the Latin word terminus, in reference to the leaves being found at the ends of the branches. The leaves are leathery, broad-ovate, lustrous, dark green. They are spirally arranged in rosette-like clusters at the branch tips. And they are big: 15–25 cm (5.9–9.8 in) long and 10–14 cm (3.9–5.5 in) broad. It is a deciduous tree, leaves turn red before dropping.
Separate male and female flowers grow on the same tree. Both are inconspicuous with no petals, small 1 cm (0.39 in) in diameter, white to greenish. They appear at axillary or terminal spikes. The fruit, cherry-like, is a drupe 5–7 cm (2.0–2.8 in) long and 3–5.5 cm (1.2–2.2 in) broad, green at first, ripening to red, containing a single edible seed, likened to an almond — hence the name given to the tree.
It is an important timber tree in the Maldives. The timber is strong, elastic, moderately hard, smooth and lustrous. It is brown or reddish-brown in color, rather coarse in texture. It is widely used in boat building, for the keel mainly.
The native range is maritime areas of tropical Asia, northern Australia, Polynesia, Malaysia. It has been introduced elsewhere, in Brazil for instance, as an ornamental species.
But back to the leaves: they enjoy current use as sequestering agents for heavy metal pollutants, metals such as  cadmium, chromium, lead, mercury, silver, … Such a practice occurs in countries such as India primarily, Ethiopia, Guyana, Nigeria, … What happens to the leaves after they have soaked up the pollutants ? One should hope for recovery of the heavy metals, rather than a massive dump that, at least, would be localized and identified.
My hunch is that the large format of the leaves, their abundance as well, led to such an application. Probably many other trees would provide broad leaves also capable of similar bioremediation. I can only recommend the FAO site on the Web that lists and beautifully illustrates such species, ‟Broad leaved trees and shrubs‟ (http://www.fao.org/docrep/010/ai387e/AI387E05.htm).