It's a political allegory about the US pushing Canada around. And what Canadians would do to the US if they had the wherewithal to turn the tables.
And they'd do... what? Put a tax on hockey? Take back Niagara Falls?
"Niagara Falls! Slowly I turned...."
They'd cut us down to size (literally, see the bolded part).
There is unrest in the forest
There is trouble with the trees
For the maples want more sunligh
And the oaks ignore their pleas
The trouble with the maples
(and they're quite convinced they're right)
They say the oaks are just too lofty
And they grab up all the light
But the oaks can't help their feelings
If they like the way they're made
And they wonder why the maples
Can't be happy in their shade?
There is trouble in the forest
And the creatures all have fled
As the maples scream `oppression!`
And the oaks, just shake their heads
So the maples formed a union
And demanded equal rights
"the oaks are just too greedy
We will make them give us light"
Now there's no more oak oppression
For they passed a noble law
And the trees are all kept equal
By hatchet,
Axe,
And saw ...