Symbols - What does heaven look like
Woodhenges
See Trees and sacred groves.
The sacred nature of trees resulted in ancient cultures recreating sacred groves in wood. Thus a wood circle is simply a sacred grove recreated as a temple structure.
Paul Devereux – Sacred Places
We can be sure that such veneration of trees went far into European prehistory, but because trees eventually perish we cannot see them still as we can say, mountains. What modern archaeology in Britain, using not only excavational methods but also electronic, geophysical detection techniques has begun to reveal, however, is the extent to which timber was used in prehistoric sacred sites and we now know that Stone Age people were also ‘Wood Age’ people building timber circles as well as stone ones and even what appear to have been great timber temples, for example, Woodhenge. Around 50 such sites have been detected in Britain

This timber structure near Stanton Drew, Somerset, for example, has 500 posts in 9 concentric rings, was over 300 foot in diameter and stood 30 foot high. One at Avebury was 600 feet across and spanned the Kennet stream. It used oak posts over 30 foot high, 66,000 foot of timber is estimated to have been used. The structures were encircled by a Water ditch and Earth ramparts. The central sanctuary was usually accessible by one bridge. There is also evidence that Fire was used in a symbolic sense. With the sanctuary protected by a wall of flame during ceremonies.

At Seahenge (Holme Timber Circle pictured above), the central feature was found to be the stump of a giant oak tree that had been placed upside down into the ground with its roots in the air – see Tree of Life. Dating of the tree using the tree rings and carbon dating put it at 2050 BC. There are other examples of felled or uprooted oaks being used as central posts in tent like structures e.g. in Navan Fort Armagh, Northern Ireland the oak tree was 36 foot high.
Most central trees symbolically represent the tree of life. The upside down placing of the tree with its roots in the air matches exactly the symbolism you can see in the section on the tree of life.
The choice of tree as symbol, however, could sometimes depend not on its symbolic meaning but on the type of hallucinogenic substance it supported!
Paul Devereux – Sacred Places
The Samoyed (Nenets) of Northern Russia had a major tree sanctuary at a place known as Kozmin Copse… Researchers have found offerings fixed to the trunks of well over 200 trees on both sides …. The offerings included bells, metal discs, bronze and copper items, rings and even buttons. Most were fixed to birch trees, regarded as sacred trees throughout Europe possibly because it shares a symbiotic relationship with the hallucinogenic fly agaric mushroom, which was used for trance purposes by many Eurasian shamans