Let me take you back in time, when The Stories were born. This one comes from The First Nation folklore.
It was a hot day, and Old-man was trying to sleep, but the heat made him sick. He wandered to a hilltop for air; but there was no air. Then he went down to the river and found no relief. He travelled to the timberlands, and there the heat was great, although he found plenty of shade. The travelling made him warmer, of course, but he wouldn't stay still.
"By and by he called to the winds to blow, and they commenced. First they didn't blow very hard, because they were afraid they might make Old-man angry, but he kept crying:
"'Blow harder -- harder -- harder! Blow worse than ever you blew before, and send this heat away from the world.'
"So, of course, the winds did blow harder -- harder than they ever had blown before.
"'Bend and break, Fir-Tree!' cried Old-man, and the Fir-Tree did bend and break. 'Bend and break, Pine-Tree!' and the Pine-Tree did bend and break. 'Bend and break, Spruce-Tree!' and the Spruce-Tree did bend and break. 'Bend and break, O Birch-Tree!' and the Birch-Tree did bend, but it wouldn't break -- no, sir! -- it wouldn't break!
"'Ho! Birch-Tree, won't you mind me? Bend and break! I tell you,' but all the Birch-Tree would do was to bend.
"It bent to the ground; it bent double to please Old-man, but it would not break.
"'Blow harder, wind!' cried Old-man, 'blow harder and break the Birch-Tree.' The wind tried to blow harder, but it couldn't, and that made the thing worse, because Old-man was so angry he went crazy. 'Break! I tell you -- break!' screamed Old-man to the Birch-Tree.
"'I won't break,' replied the Birch; 'I shall never break for any wind. I will bend, but I shall never, never break.'
"'You won't, hey?' cried Old-man, and he rushed at the Birch-Tree with his hunting-knife. He grabbed the top of the Birch because it was touching the ground, and began slashing the bark of the Birch-Tree with the knife. All up and down the trunk of the tree Old-man slashed, until the Birch was covered with the knife slashes.
"'There! that is for not minding me. That will do you good! As long as time lasts you shall always look like that, Birch-Tree; always be marked as one who will not mind its maker. Yes, and all the Birch-Trees in the world shall have the same marks forever.' They do, too. You have seen them and have wondered why the Birch-Tree is so queerly marked. Now you know.
Source: Frank Linderman's 1915 collection Indian Why Stories.