ocr: Sequoia some of the growth rings, each corresponding toa a significant historical event. Note that even one thousand years ago, represented by the fourth mark from the center, this was a very big tree. These rare and remarkable natural treasures grow in sixty-three groves scattered along the western slopes of the Sierra Nevada Mountains. Containing from as few as six to many thousands of trees, the groves cover a total of about fifteen thousand acres at elevations of twenty-nine hundred to eighty-eight hundred feet. Today, it is illegal to cut down giant sequoias. 66