It is a cultural icon whose rasping, eerie sounds evoke the mysteries of Aboriginal Australia. But its recent popularity could be the death of the didgeridoo. The wind instruments have become so popular with tourists that large areas of bush land are being illegally harvested for the wood from which they are made. A genuine didgeridoo is fashioned from a tree branch which has been naturally hollowed out by termites. It takes skill to find such branches, a skill that was until recently the preserve of Aborigines. Likely-looking limbs are now being taken by non-indigenous Australians, who often damage several trees in order to find one suitable branch. The axes used by Aborigines have given way to chain saws. So widespread is this poaching that Aborigines in the Northern Territory are calling for controls on who is allowed to make didgeridoos, while Western Australia requires labels showing didgeridoos have been produced sustainably. In the Northern Territory, white Australians are allowed to harvest branches suitable for didgeridoo-making if they have a permit from the Parks and Wildlife Service. But experts say the number of didgeridoos sold by souvenir shops in Darwin and Alice Springs far exceeds the number that permitted harvesters are able to make. Josh Forner, from the Tropical Centre for Wildlife Management in Darwin, told ABC radio: 'I'd say the majority of didgeridoos are harvested without a permit. Permits [issued by the Parks and Wildlife Service] each year average about 1,500 but a didgeridoo shop in Darwin could sell between 5,000 and 10,000 a year.' Aboriginal leaders say permits should either be reserved for Aborigines, or granted on a limited basis to white Australians on the understanding that part of the profits from the sale of didgeridoos is ploughed back into indigenous communities. The problem has become so acute in Western Australia that two years ago a tagging system was introduced by the state's Department of Conservation and Land Management. Licensed woodcutters attach a label to each branch they remove, which remains on the wood throughout the didgeridoo-making process. Selling or owning a didgeridoo without a tag is an offence. In Western Australia alone, between 1,000 and 2,000 branches are cut each year from mallee trees, a kind of eucalyptus. Stems are sold for about A$50 (HK$221) while a finished didgeridoo fetches at least A$150. Each one is unique, with its own sound. Many Aboriginal people say that the system, no matter how well intentioned, misses the point. They say that didgeridoos should not be cut or made by non-Aboriginal Australians, and are offended by the appropriation of an instrument they consider sacred.