Trees, Fruits and Flowers of Minnesota, 1916
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"DON'TS" ISSUED TO PREVENT FOREST FIRES.--1. Don't throw your match away until you are sure it is out.
2. Don't drop cigarette or cigar butts until the glow is extinguished.
3. Don't knock out your pipe ashes while hot or where they will fall into dry leaves or other inflammable material.
4. Don't build a camp fire any larger than is absolutely necessary.
5. Don't build a fire against a tree, a log, or a stump, or anywhere but on bare soil.