Didn’t say anything about it being an iron civilization.
Even felling big trees doesn't need iron tools - controlled fire will do most of the work: http://www.cherokeeheritage.org/attractions/dugout-canoe/
https://youtu.be/zVPUFMwm73Y?t=228
Relevant: Coppice
https://en.wikipedia.org/wiki/Prehistoric_pile_dwellings_aro...
Not fine woodworking, perhaps, but possible.
Most early construction was based on found shelter (caves), hides, sod or turf, brick, or stone. Locally-available and hand-workable with very simple tools.
Ale native American lodgehouses and pueblos (adobe walls, timber roofs), also stone tools.