- [Mark] This is Mark Isselhardt,
maple specialist with University of Vermont Extension,
and this is another Vermont Maple Minute.
A modern tubing operation
relies on a tubing system with vacuum
to maximize sap production.
The innovation of plastic tubing
originally came as a labor-saving device
and not to increase sap yield from an individual trees.
As the materials used to produce maple tubing
became more robust and vacuum pumps were employed,
the increases in sap yield became obvious.
There are many questions about how the use of vacuum tubing
does or does not impact the tree
or the sap harvested from the tree.
Research at the University of Vermont
Proctor Maple Research Center
sought to answer some of the common questions.
To answer the question
if the naturally occurring concentrations of minerals
change as more vacuum is applied to the taphole,
groups of trees were tapped
and exposed to various levels of vacuum
ranging from 15 inches to 25 inches of mercury.
Inches of mercury is a unit used in weather reporting
and is a measurement of intensity of vacuum.
A control treatment with no applied vacuum
was also included.
Samples of sap were collected throughout the season
and analyzed for the most abundant,
naturally occurring minerals in sap.
The results indicate
that compared to sap collected using vacuum,
sap collected from gravity had similar concentrations
of calcium, phosphorus, potassium,
magnesium, iron, and manganese.
As with many experiments,
the results lead to more questions
and the need for additional research.
This is Mark Isselhardt,
maple specialist with the University of Vermont Extension,
and this has been another Vermont Maple Minute.