Is Pope's "Windsor Forest" a celebration of Britain and its empire?
Definintely. This poem is an evocation of place above all, as the title suggests, but Pope uses the description of this place to present his view of the moral and physical superiority of Britain and how he hopes that this is something that will be recognised by the entire world through the colonial enterprise. Note the following quote:
Unbounded Thames shall flow for all mankind,
Whole nations enter with each swelling tide,
And seas but join the regions they divide;
Earth's distant ends our glory shall behold,
And the new world launch forth to seek the old.
Then ships of uncouth form shall stem the tide,
And feather'd people croud my wealthy side,
And naked youths and painted chiefs admire
Our speech, our colour, and our strange attire!
In these lines, Pope imagines the river Thames, which is "unbounded" by geography or any other limitation, entering every single nation via the oceans so that the "glory" of Britain can be seen at "Earth's distant ends." He then goes on to contemplate a coming of all distant peoples to London to see the glories of Britain, imagining "ships of uncouth form" and "feather'd people" coming to London to meet the Old World that they are so impressed by. This is a poem therefore that is all about the might and supremacy of Britain and how this makes them a leading world player in Pope's time.