FOR rent: 830,000 hectares of pristine tropical rainforest. Rich in wildlife, including forest elephants and gorillas. Provides a regionally important African green corridor. Price: $1.6m a year. Conservationist tenant preferred, but extractive forestry also considered. Please apply to the Cameroonian minister of forestry.

That, in essence, is what the government of Cameroon has been offering since 2001 in an attempt to make some money from a forest known as Ngoyla-Mintom. The traditional way would be to lease the land to a logging company. But Joseph Matta, the country's forestry minister, would rather lease it to a conservation group. The trouble is, he cannot find one that is prepared to take it off his hands.

The idea of conservation concessions has been around since 2000. It was introduced by an American charity called Conservation International, which realised the going rate for logging concessions was often so low that it could afford to outbid the foresters. It has since leased forests in Guyana—where it has 80,000 hectares of Upper Essequibo—and in Peru, Sierra Leone, Papua New Guinea, Fiji and Mexico. But even in 2001 it reckoned that at $2 a hectare Ngoyla-Mintom was too dear. Its land in Essequibo costs a mere 37 cents a hectare.

Mr Matta, of course, thinks Ngoyla-Mintom is worth every penny. Indeed, the price has gone up. The government now wants additional money to compensate Cameroon for forgoing the jobs and local development that come with logging. The forest is pristine habitat of a sort likely to contain some extremely valuable pieces of timber. It also connects three other large protected areas (see map), and thus forms an important part of a regionally important green corridor. Mr Matta says that if one group of conservationists or another doesn't cough up soon, he really will be forced to get on the phone to the loggers.

A compromise put forward by the World Wide Fund for Nature has failed to find favour. The WWF suggested keeping an unexploited core of Ngoyla-Mintom while the rest is opened to limited “sustainable” hunting and forestry. The quid pro quo would be a lower rent.

Cameroon, not surprisingly, would prefer the higher rent. Mr Matta also points out that even a little forestry would mean building roads that will present additional threats to the area. Ngoyla-Mintom is thus turning into an interesting test of what the conservation market will bear. There is a willing seller, but not yet a willing buyer. The fine words of the rich-world's armchair conservationists butter few parsnips in the poor world. Here is a good opportunity to spread some butter.