these items have the blocktag #minecraft:saplings but are missing the item tag #minecraft:saplings
('productivetrees:black_ember_sapling')
('productivetrees:brown_amber_sapling')
('productivetrees:cave_dweller_sapling')
('productivetrees:firecracker_sapling')
('productivetrees:flickering_sun_sapling')
('productivetrees:foggy_blast_sapling')
('productivetrees:night_fuchsia_sapling')
('productivetrees:purple_spiral_sapling')
('biomesoplenty:red_maple_sapling')
('productivetrees:rippling_willow_sapling')
('productivetrees:slimy_delight_sapling')
('productivetrees:soul_tree_sapling')
('productivetrees:sparkle_cherry_sapling')
('productivetrees:thunder_bolt_sapling')
('productivetrees:time_traveller_sapling')
('productivetrees:blue_yonder_sapling')
('productivetrees:water_wonder_sapling')

I know, it was an unfortunate necessity to prevent cheesing with mods that allow you to change one sapling into another

Ahh ok wasn't sure if it was intended or not