birchbarks

At first sight you would never believe that sea-power could be lost or won as well by birchbarks as by battleships.

Flag and Fleet How the British Navy Won the Freedom of the Seas William Charles Henry Wood 1905

They used birchbark canoes a great deal at Roaring Water Portage in the summer-time, but there was too much ice about for birchbarks to be safe yet.

A Countess from Canada A Story of Life in the Backwoods Bessie Marchant 1901