I think some of the wise, sacred salmon in wells are said to have got their wisdom from eating hazelnuts that fell into the water.

Burl gives rather a good description of what was in the primary mound under Silbury Hill, (or in the middle if Pete's around) to set the picture it was probably late summer.
First they erected a circular hurdle-work fence of spaced stakes. At the centre they heaped clay with flints which were specially brought to the mound. The builders then covered the mound with a stack of turfs, then topsoil - containing great quantities of moss in comparative freshness. A few sarsen boulders were scattered around the base and "on top of these were observed fragments of bone, and small sticks, as of bushes and ... of mistletoe.... and two or three pieces of the ribs of either the ox or the deer" (this quoted under "rubbish" by Merewether-1849). Burl puts these relics as offerings to the the "spirit" world of the fecund world desired by these farmers.. What is evident from Writtle's summing up, is that there were a lot of wild flowers in the grasses round Silbury, something not many people take note of..

And here's one of my favourite celtic stories, taken from Ann Ross- Pagan Celtic Britain.
Finn and the Man in the Tree;
One day as Finn was in the wood seeking him he saw a man in the top of a tree. A blackbird on his right shoulder and in his left hand a white vessel of bronze fillled with water in which was a skittish trout and a stag at the foot of the tree. And this was the practice of the man cracking nuts; and he would give half the kernel of a nut to the blackbird on his right shoulder, and the other half he ate himself; and he would take an apple out of the bronze vessel that was in his left hand, divide it in two, throw one half to the stag and then eat the other half. And he would take a sip of the water in the bronze vessel that was in his hand so that he and the stag,and the trout and the blackbird drank together.......
The man is Dercee Corra Mac Mac Hui Daighre - The Peaked Red one -, probably a cloak of disguises, which Ross goes on to say may lay behind the small representations of the "genii cucullati". Theres a relief of these three hooded figures found in Bath.,

Underneath this hazelin mote,
There's a braggoty worm with a speckled throat,
Nine double is he,
Now from eight double to seven double
And from seven double to six double
(and so on)
And from one double to no double,
No double hath he.

(An old charm for curing an adder bite).

Hazel certainly seems to have been credited with 'magical' properties. There was a small (about 6" long) hazelwood wand on show during the recent Witchcraft Exhibition at the Essex Record Office (not sure if the exhibition has finished or not). Hazelmead, made from hazelnuts, may have had psychotropic if not magical properties (or is that one and the same thing?) and reminds me of the recent discussion we had about the possible psychotropic properties of the yew.

"I went out to the hazelwood, Because a fire was in my head..."

W B Yeats

If I remember rightly I think that hazel is one of the first trees to re-colonise woodland clearences. I've read that small woodland clearances may have occured during the Mesolithic specifically to encourge the growth of hazel and ensure a ready source of high protein food which could be gathered and set aside against a bad winter.
I guess the people of later times would have continued cultivating these autumnal larders

Hi Peter

Seem to recall there's a well called Silvernut Well close to Otterburn in Northumberland. And not too far away a hillfort on a hill named Colwell Hill.
Can't find anything on the history of either at the moment but maybe someone else knows?