The Druids, who celebrated the solstice festival of Yule-tide, held all trees sacred. Among the vestiges of Druidism incorporated into Christmas (decking the halls being the most prevalent), the custom of wassailing the apple trees was preserved in parts of Britain for many years. Here is W. Winwood Reade's account of the tradition:
From the apple-tree the Druids were wont to cut their divining rods. And to this tree at Christmas, in Devon, Cornwall and other counties a curious ceremony is paid. The farmer and his laborers soak cakes in cider, and place them on the trenches of an apple tree, and sprinkling the tree repeat the following incantation:
After which they dance round the tree and get drunk on the cider which remains. They believe that if they did not do this the tree would not bear.
Here's to thee, old apple tree!
Whence thou mayst bud,
and whence thou mayest blow.
Hats full! Caps full?
Bushel, bushel, sacks full!
And my pockets too! Huzza!