Here it is full:

In the woods there grew a tree
And a fine fine tree was he

And on that tree there was a limb
And on that limb there was a branch
And on that branch there was a nest
And in that nest there was an egg
And in that egg there was a bird
And from that bird a feather came
And of that feather was
A bed

And on that bed there was a girl
And on that girl there was a man
And from that man there was a seed
And from that seed there was a boy
And from that boy there was a man
And for that man there was a grave
From that grave there grew
A tree

In the Summerisle,
Summerisle, Summerisle, Summerisle wood
Summerisle wood.

From the website: http://www.wicker-man.com/musicofthewickerman.php