The key to finding this one was searching for "Round Gordon Castle the woods are green," not "...Gordon's...."

Lyrics copied from The Strathspey Server:

THE DUCHESS TREE
From the Logie Collection (1888),
words by W.M.
key of Ab

Round Gordon Castle the woods are green,
And the flow'rs are fair to see;
And dear is the shade of the leafy screen,
When we meet by the Duchess Tree.

When my heart is stirred at the whisper'd word
Of the voice so dear to me;
And the rustling leaf and the warbling bird
Sound sweet in the Duchess Tree.

Let the gay lamp gleam on the glowing dance,
In the halls that ring with glee;
Far sweeter tome is the moonbeam's glance
Through the boughs of the Duchess Tree.

Like the queen of the glade, it stands arrayed
In the pride of high degree;
And long may the axe and the woodman's blade,
Spare the boughs of the Duchess Tree.

Blest be the hour in a day that is dead,
When its shoot first waved on the lea;
And blest be the hand that reared and spread
The bower of the Duchess Tree.

The world is cold like its great god, gold,
And life is a stormy sea;
But there's peace and rest, where the green boughs fold
Like a robe round the Duchess Tree.