Date: 3/16/2021
On March 4, the Chicopee Herald carried a very interesting article on local maple syrup production. I make maple syrup in my backyard and sell it at farmers markets. I have two degrees in forestry.
When I was in college in 1962, my professor said the cause of sap flow wasn't fully understood. One of the producers in your article stated that when it’s cool, sap goes down the tree, and comes back up when it’s warm again. This is incorrect.
When the temperature is above freezing, sap flows, but the phloem (sapwood) tubes which carry the sap gradually become clogged. During freezing temperatures, sap freezes in place in the phloem tubes. Sap,like water, expands when it freezes. This enlarges the tubes, and so when the sap returns to the liquid state, the sap is able to flow again.
Thank you again for your article.
Jonathan Tetherly
Chicopee
