Can you make this sentence with 'si on ne fait rien'?
Yes, you can.
I wonder if we can make this sentence with sinon ? Please enlighten me.
And any reason to reject ce bois au lieu de cette foret ?
That would need a substantial change in the structure, especially turning "si nous ne faisons rien" into the affirmative voice:
"Un bois" is smaller than "une forêt".