When is sap flow the highest?

[toomanyknots]

Just wondering for the best time to cut staves so the bark il peel right off. Last year I don't remember but it might of been the begining of summer or something that it was good for me. I know the maple suger saying is when the nights are cold and the days are warm. But I don't know if this is for when it just starts, and later it gets really going,

[Pat B]

After the leaves are 3/4 the way out or later. Depending on where you live it could be from now until mid may. Mid May to early Just is probably ideal for my area.
  Some folks like to wait until later in the summer so the full ring for this year has been laid down. I prefer early in the growing season when just enough of the cambium has started to lay down a new ring so the bark peels off easily. This way my back ring is last years new ring and it has had all fall, winter and spring to mature and harden off so my back ring is as solid as possible.

[toomanyknots]

Sweeet. Thank ya pat. As always, the info is greatly appreciated. Thank you!

[beetlebailey1977]

Great tip Pat

[DarkSoul]

It greatly depends on the species. Birch is odd enough to have the highest sapflow late in winter, when there aren't any leaves yet. However, most trees have the highest sapflow in early summer, when there are many leaves on the trees. Needle leaf trees, such as juniper or yew, have sapflow all year round (as long as it isn't freezing).
High sapflow doesn't automatically mean the bark and cambium sheds off the easiest, though. Some trees just won't peel at all, while others can even be peeled when sapflow is fairly low.

[toomanyknots]

"It greatly depends on the species. Birch is odd enough to have the highest sapflow late in winter, when there aren't any leaves yet."

Wierd. Crazy wierd. Did not know that.

[Pat B]

Birch was also used for making sugar like with maples.
  I don't think the sap flow and bark slipping necessarily go together. They both happen in spring and the sap flow contributes to cambium growth which in turn allows the bark to slip but sap flow comes first I think.