For many people, the moors in the east of England conjure up images of vast fields of wheat, potatoes and sugar beets.
However, research has revealed that this flat, low-lying agricultural landscape was once a vast forest full of giant yew trees.
Scientists examined hundreds of tree trunks dug up by Fenland farmers while plowing their fields.
They found that much of the ancient wood came from yew trees that grew 4,000 to 5,000 years ago in the area, a 1,500 square kilometer stretch of fertile land covering parts of Lincolnshire, Cambridgeshire, Norfolk and Suffolk.
They believe the trees died suddenly about 4,200 years ago after rapidly rising sea levels (possibly linked to climate change) flooded them with salt water.
The trees were perfectly preserved by the peat in which they fell and were discovered thousands of years later.
Several hundred years ago, the land above was drained and turned into farmland.
“Finding these very old trees on a moor is completely unexpected – it’s like turning a corner in Cambridgeshire and seeing an Egyptian pyramid – you just don’t expect it,” says Tatiana Bebchuk from the University of Cambridge.
“Wood rots and decomposes easily, so a tree that died five or four thousand years ago cannot be expected to live that long.”
“A common nuisance for Fenland farmers is that their equipment gets stuck in large pieces of wood buried in the ground, which often happens when growing potatoes as they are planted a little deeper than other crops,” she said.
“This wood is often dug up and piled up at the edge of the field: these huge piles of wood can be seen quite often when driving through the area.”
Fallen trees can be a nuisance by blocking farm equipment, but they provide a wealth of information about what the marsh looked like in the past, the researchers said.
Yews are one of the longest living species in Europe and can grow up to 20 meters in height.
Most peatlands barely rise above sea level, and a sudden rise in sea levels around 4,200 years ago would likely have killed off the peatlands, according to the researchers.
The period of extinction of the Vienna Woods coincided with serious climate changes in other parts of the world.
Around the same time, a megadrought in China and the Middle East may have triggered the collapse of several civilizations, including the ancient Egyptian kingdom and the Akkadian Empire in Mesopotamia.
Although these trees are quite common in the gardens and cemeteries of Cambridge College in southern England, they are not found in the Fens, a low-lying, marshy area in eastern England.
Much of Fens was marshy land until it was drained through artificial drainage and flood control in the 17th to 19th centuries.
Today the area is one of the most productive agricultural areas in the UK thanks to its fertile peat soil.
The study was published in the journal Quaternary Science Reviews.