A list of tappable trees and syrups.

[Sandersyrup]

I'm looking to create a more definitive list of trees that can be tapped for sugar. Very very low brix is not a concern, just a list of plausible syrup trees specifically through tapping so blue spruce and other bark boiled syrups are not a part of this list.

A little searching on the internet and I have found comments about the following trees.

Trees that definitely bleed sap and can make syrup during springtime:
Maple (all Acer)
Walnut (all Juglans)
Birches (some Betula)
Hickory (all Carya)
Palm (some Palmae) not so much springtime.

Trees that definitely bleed sap during the springtime. Quality, edibility and sugar unknown.
Beeches (Fagus)
Elms (Ulmus)
Grapes (Vitis)
Lindens (Tilia)
Mulberries (Morus)
Poplars (Populus)

I have heard that Apple trees can be tapped but can't verify it.

I ask because my neighbor has a bunch of pear trees he wants to know if can be tapped. He does not like the pear fruit quality.