The resinous stumps and pitchy pine logs have been chopped into 70-centimetre pieces, which are stacked by hand to make something shaped rather like a round loaf of bread. Stacking is exact work, because hardly any space can be left between the pieces of wood.
Over a thousand cubic metres of wood was used in the giant pit in Lentiira. Resinous species, especially pine, yield the best tar. The pit, 23 metres in diameter at the top, is shaped like an inverted cone, the tip of which is a couple of metres below the ground surface. The tar runs out through pipes in the bottom of the pit.
The fire had to be lit at several places around the circumference of the stack at exactly the same time. This pit had a circumference of 73 metres, so dozens of people had to be ready with their matches. Once the wood is burning, the edges are also covered with peat and, almost completely cut off from oxygen, the fire smoulders on. As the wood burns the pile shrinks and the tar flows down to the hole - called the "eye" - in the bottom of the pit and through it into pipes.
A "tar dance" celebrating the firing of the Lentiira pit.
Even at the latitude of Lentiira, the nights grow dark in August. Here, the world's biggest wood tar pit glows like an odd volcano in the northern night.
As it smoulders a wood tar pit belches out an impossible volume of smoke. It has to be watched day and night, and any incipient flames doused at once. While the pit is smouldering, the peat cover is whacked with wooden cudgels to keep it dense and poor in oxygen. Wherever a hole has been burned through the peat, it is immediately patched.
The tarmakers in Lentiira made one small concession to modernity by using steel pipes rather than the traditional ones made of hollowed-out trees. More tar is recovered when steel pipes are used, but they were hidden inside tree trunks anyway.
The tar that flows from a pit is not immediately ready for use. For one thing, it contains water and other substances that have dissolved into it, creating what is colourfully called "tar piss". These foreign substances are removed by letting the tar stand and skimming them off. The world's biggest wood tar pit smouldered for two weeks, yielding 35,000 litres of tar and thousands of litres of by-products. It sold well. The Lentiira pit yielded enough tar to treat the shingle roofs of many churches.