i had in mind that there could be the option to add more compatible trees using crafttweaker (the user only needs to add the block of the tree he wants to get syrup). or if you want, a config option to add these blocks without crafttweaker (please consider metadata)

hey, i saw that you are moving to 1.15, well i don't have nothing against it, but i only can say that you could consider still supporting 1.12 mostly because of Heat&Climate, i don't have the enough time to test mods right now, but i think that there could be something more than OreDict or recipes that you could implement compatibility with Heat&Climate