I think historians have a methodological commitment to using “actors’ categories” in their research, to maintain a historical context for causal relationships. Situating discourse in terms of how actors perceived their world helps avoid presentism and also helps engage with the concepts they used to understand themselves and others. It seems “frontier” was/is an active word with multiple meanings–and if so, presents itself as a rich historical document in itself to be unpacked by us researchers.

Constance may be referring to Cronon’s The Trouble with Wilderness article–http://www.williamcronon.net/writing/Trouble_with_Wilderness_Main.html.

All the best-
Andrew