Quote Originally Posted by GeneralStark View Post
6" trees will certainly produce sap, especially if they are vigorous, but if they are suppressed in the understory which seems likely at your density, they will likely slowly succumb to tapping and may not do well if something removes the dominant trees.
At the very least with that level of crowding you are slowing down the growth of all the trees, whether they are tapped or not. You can think of tapping and collecting the sap as an interest rate that you are asking the tree to pay each year you tap it. With a big tree, the interest might amount to a couple of percent. With a small tree (6") on vacuum, you're asking it to pay 15-20% interest -- that is a lot. They'll deal with that level of impact for a while, but it will definitely reduce their vigor and increase mortality in that stand within a 5-10 yr time frame.

The better approach is to thin the stand to allow the crop trees to grow faster. Faster growing trees produce MORE sap and SWEETER sap. You'd probably make more syrup from that stand with fewer trees with higher production rates than you would with it being very high density. Plus it would require less infrastructure (tubing, drops, and spouts) and there would be a reduced opportunity for leaks.

I definitely understand the "thinning with a tapping bit" concept, and it does have its time and place, but it should be used sparingly and is certainly a poor substitute for a good thinning.

Pick your crop trees by looking at spacing, form (good straight stems without root or stem defects), and most importantly, sap sugar content (which you can test with a refractometer).