Deep in the woods.(Focus on Poland)

Once hunting grounds for Polish monarchs, Bialowiezski National Park has welcomed back the European bison

In Eastern Poland there is a 650-year-old oak tree. It grows straight and tall like a fir tree before its canopy bursts into life about 40 metres up. The ancient tree is dying now but its gnarled trunk will remain standing for many years, supporting a community of living organisms. When it finally topples, mushrooms, bigger and more mouthwatering than anything you can imagine, will grow on its decaying bark.

The tree is perhaps the oldest in the vast 150,000-hectare Bialowieza Forest, the last lowland primeval forest in Europe. Stretching across the former Soviet Russian border into Belorussia, the forest has existed since the last Ice Age, about 10,000 to 12,000 years ago. Only part of the forest is protected. Bialowieski National Park, Poland's first national park established in 1921, covers just 10,500 hectares of the forest.

The geographical location of the forest has played an important part in its preservation; as the borders of Poland have changed many times under Russian, Prussian and Austrian rule, Bialowieza has often found itself in no-man's land.

A two-metre high wire border fence cuts through the trees, a reminder that although the forest is wild it still falls under national laws. Even the forest's animals are separated by nationality. Wolves live in the national park along with European bison (reintroduced in the 1950s), elk, stag, wild boar, lynx, pine marten, otter and beaver. The only species missing is the bear, hunted to extinction in the 1870s.

The European bison is the largest mammal in Europe and weighs up to 1,000 kilograms. In 1916, the population of bison living in Bialowieza Forest was 150. They were totally wiped out three years late, with the only surviving ones living in zoos. In 1929, however, several of the zoo animals were brought into the forest to breed. The breeding programme has been successful and today there are about 250 bison roaming freely in the forest. More than 350 have been sent to other places in Poland.

Black alder grow in the boggy parts of the forest. It is the only tree that can grow in the humidity and stagnant water. When the alders die, saplings take root on their dead trees until they too can grow in these dank hollows.