Drop Trees Before The Sap Runs?

[GeneWengert-WoodDoc]

WDH--
I thought that the sap moves up in the wood and down in the bark (phloem).  That is what I was taught and what I see in textbooks too.

[beenthere]

Xylem up and phloem down.

WDH pointed out it wasn't in the sapwood wood.  But then I don't have a PHD

[WDH]

Yep.  That is right.  My interpretation of "sap" was the sugars produced in the crown and translocated to the roots via the phloem.  However, probably, most use of the term "sap" would be any liquid flow in the tree, up or down. 

The confusing thing is that moisture content in the wood does not vary drastically year round, so what does "the sap is up" even mean?  Maybe it means that the crown is actively calling for water to start the growth engine, and water is being actively translocated to the growing crown. 

[POSTON WIDEHEAD]

...... sugars produced in the crown and translocated to the roots via the phloem.   

say_what

[WDH]

The roots have to eat.

[Peter Drouin]

Up and down up and down I don't know but I can only make mayple syrup in the spring, I think something is going on in the tree :D :D :D ;)

[Stephen1]

Up and down up and down I don't know but I can only make mayple syrup in the spring, I think something is going on in the tree :D :D :D ;)

Actually you can make syrup in the fall.I read an experiment years ago where they made syrup in the late fall when there were some cold nites and warm days. The issue was there not as much syrup was made. It added to many holes in the trees as they still tapped in the spring. It was hard to clean up and put things away as winter had set in. The best part was that it was easy to get around and tap without  snow up to your waist 8)

[ArborJake]

 Pressure built up by gases wich develope when the sap freezes and then thaws is the main reason you can tap trees in spring and fall. When the pressure inside the tree is greater than the pressure outside the tree in flows out. Whenever a low pressure system moves through the area id get lots of sap. If it stops freezing at night. You wont get sap. That is also how a vaccum pump works for increasing sap yeild. It creates slightly lower pressure just outside the tap hole.