Small bubbles coming out of a cut maple stem under vacuum 

Sap sugar content is comparable to a mature tree. This sapling was growing out in the open however. Sap collection from a 2" stem with 25" Hg vacuum will yield a little under a gallon of sap over the season. However, on a per acre basis, this style of collection will yield up to about 10X the amount of syrup compared to typical production in a high-density maple plantation.

​@@UVMProctorMapleResearchCenter and does the 2" stem heal enough to cut and "retap" the next season

In a plantation setting, the stem will vigorously resprout new branches just below the cut. The approach is to recut the stem about 5-6" below the original cut. Better yet, choose a multi-stemmed sapling and rotate to a different stem each year so it takes 4-6 yrs to return to the originally cut stem. For regenerating in woods, regrowth is less vigorous, but still happens. Basically, this resprouting is similar to what happens when saplings are browsed by deer. Many species (including maple) are well adapted to handle this. @@shawntobin-ii9cq

Thank you ​@@UVMProctorMapleResearchCenter

Not at all. Essentially we are making the stem akin to a sugar-filled straw in the ground. By putting a strong vacuum on the cut stem, we are pulling water out of the soil and up through the stem and out of the cut top where we can collect the sweet sap and boil it down to make maple syrup.