Interpret however you want

Bigleaf Maple

I set out in the fall for the east
Bigleaf maples yellow against the green douglas fir
The grey skies faded into the green
At the top of the pass

And the trees change in the east
Ponderosa pines and quaking aspen
Still yellow and green
But the skies blue at last

Until you climb to the north
Into the tallest mountain's silver country
Where golden larch grow
Against cuts of green argillite