The increment borer is a special tool designed to remove a corefrom the tree trunk. Counting the rings on the core corresponds to counting the rings on the stump. To show annual rings in the classroom, use a cross-section of a small tree limb. Many species of evergreen trees send up a whorl of new branches each year. By counting the number of branch whorls you can determine the age of the tree.
Whorls are the layers of branches that grow from the main trunk.
The sap of trees does not go into the tree roots in winter. Sap stays distributed throughout the tree during the entire year. The big difference between summer and winter is that in winter very little movement of the sap occurs. When the warm days of spring approach, the sap begins to move as the tree becomes active. Spring is the time when we tap maple trees for sap to make syrup.