1. Maple Syrup in the Classroom Lesson 3 Sap Movement Physiology

2. Maple Syrup in the Classroom SAP… Too Move or Not Too Move? Many factors effect sap movement during the syrup season. – –Freezing Nights and Warm Days – –Minimum and Maximum Temperature – –Length of Freeze and Thaw – –Availability of Soil Moisture – –Sap Sugar Concentration – –Barometric Pressure 3.1

3. Maple Syrup in the Classroom The Details Freezing temperatures cause the gases in the tree (CO 2 and O 2 ) to contract causing a negative pressure (vacuum) in the tree. This allows more water (if available) to be absorbed by the roots. Warm temperatures cause the gases to expand creating a positive pressure in the tree. 3.2

4. Maple Syrup in the Classroom The Details Cont. The taphole allows pressure to escape the tree in the form of gases and liquids (sap). This cycle continues throughout the season. Pressures of up to 50 PSI (pounds per square inch) have been recorded. 3.3