A good sap day yesterday but cold again today and maybe tomorrow before warm weather returns. The good news is that everything is running well and the syrup we have produced so far is of excellent quality.
Sap flow from the trees is dependent on two factors-the temperature and the atmospheric pressure. The temperature needs to be above freezing to warm the trees and if there are any dips in the pipe lines to thaw the lines. Sunshine on the tree tops helps to build up the pressure inside the tree to start sap flow.
The maple tree and some other tree species have open cell structures filled with liquid and carbon dioxide gas. It is the expansion and contraction of this gas with changing temperature that pumps the sap up and down the tree in the spring.The sap will run as long as the pressure inside the tree is greater than the atmospheric pressure. We often get the best sap runs when a low pressure system arrives ahead of a storm.
Snowshoes are still needed for travel in the bush off the trails. However, the snow around the tree trunks is melting allowing moisture and warm air to reach the tree roots. This allows fresh sap to be drawn up from the roots which increases the sap flow and sap sweetness.
This is brief explanation of the key factors in sap flow.However, we continue to be surprised by the vagaries of sap flow so there are still aspects we don’t fully understand.
The red shouldered hawks appeared yesterday right on schedule.They have been returning around this date for as long as we can remember. One year in late april we were thrilled to see their courtship flight.
Bright sunshine this morning and a pleasant day for a walk around the sugar bush,