This section is from the book "The Hygienic System: Fasting And Sun Bathing", by Herbert M. Shelton. Also available from Amazon: The Hygienic System Vol III Fasting and Sun Bathing.
Perhaps before we give our attention to hibernation among animals we may profitably take a hasty glance at the hibernating practices of plants. The "winter sleep" of trees, shrubs and many other plants is seen on every hand during winter. With the approach of Fall, these shed their leaves, their sap descends and they exist in a dormant state until the coming of Spring. In like manner bulbs, tubers, etc., undergo a prolonged "winter sleep." These plants fast through the whole of the winter months, taking no food during the time. They take no carbon and nitrogen from the air and extract no minerals and nitrates from the soil. Metabolism is practically non-existent during this period. The cessation of the flow of sap in trees during the winter season is similar to the almost ceasing of circulation in hibernating animals. Plants like the daffodil, onion, beet, turnip, etc., store up large supplies of food in their roots--bulbs and tubers--during the Summer. Their tops die off in the late Fall or early Winter and they lie dormant during the long Winter, only to send up new stems and leaves when Spring arrives. This storing up of food in their roots is similar to the storing of fat by the bear.