Stinging Trees

Arguably the most painful plant in the world, the giant stinging tree grows in the rainforests of coastal Queensland and New South Wales, eastern Australia. They like to grow in areas near river courses, especially in clear or disturbed areas. They are supposed to gow to about 40 metres high, but the largest ones at Barrington Tops National Park grow to about 20 metres high, with a trunk about 0.5 metres in diameter. The bark is light in colour, and older trees, you can touch the trunk without being stung.

The leaves, however, are covered in silica - glass - spikes, and when touched causes immediate pain which can last for days. The young trees grow rapidly. They are a rainforest pioneer species. The wood is very soft and if a tree is felled it will rot away within months.

The leaves of the tree are heart shaped and usually have large gaping holes in them caused by beetles. The leaves are covered in dense hairs which the tree uses to sting it predators. Each tiny silicon hair contains neurotoxin and on touch they break off and inject the venom. Even dead leaves can sting. My wife was severely stung by a dead leaf at the bottom of a shallow pool at Dorrigo National Park. It took days for the sting to subside.

There are only male flowers or female flowers on a giant stinging tree. Giant stinging trees are easily recognised from the six other species of Australian stinging tree. For starters, they are big. The tree is easily identified by its large, heart shaped leaves, covered with dense hairs. The leaves are often full of holes; this is caused by a beetle which eats the leaves. Flowers are yellow-green, and the fruit is a small nut on an expanded fleshy stalk resembling a mulberry in colour and texture. These stalks are an important winter fruit for the Green Catbird and the Regent Bowerbird.

Stinging trees grow right along the east coast of Australia. They grow only if they get both strong sunlight, and protection from the wind. Stinging trees play an important part in the ecology of a rainforest. Many native Australian animals, birds and insects are not bothered by the sting, and happily devour the leaves and fruit. Red legged pademelons - small fat wallabies about the size of a small dog, reportedly love eating the leaves. They are certainly endemic in locations where stinging tress grow.

You need thick gloves to stop a stinging tree. Cotton or denim is not sufficient to ward off a sting. The silicon hairs penetrate your skin, and then break off. They're so tiny, that often the skin will close over the hairs. So sometimes, once you've been stung, you can't remove the stinging hairs. What's worse is that you can get stung even after the leaf is dead. My wife once stepped on an almost completely rotted leaf at the bottom of a river bed, and was severely stung by the dead leaf. There are reports that the stinging hairs can be potent for decades after the leaf has died.