You've got a wonderful tree on the go here. I'm struggling to see the difference in leaf compared to a trident maple. Do you know an easy way to tell? The reason I ask is that I have some seedlings and I'd like to know if they are tridents or Amur.
Thank you.
It's really not that hard once you know what to look for and the variations that both species have in leaf shape.
Acer rubrum generally have tri-lobed leaves WITH SERRATIONS at the leading edges. Trident leaves, for the most part don't. Also, bark and twigging gives additional ID. Trident maple bark is thin and exfoliates (falls off in strips). Acer rubrum is thicker barked and doesn't really exfoliate all that much. The final thing is that acer rubrum is native to North America. Tridents aren't. If you see a tri-lobed leafed tree in the woods, it is most likely acer rubrum.
Amur maple leaves tend to have an elongated lobe in the middle of their leaves. Their leaves also tend to be smaller than acer rubrum or trident in most circumstances. They are invasive in N. America, so they pop up everywhere.
All three throw a few shape variations in their leaves, but understanding context in where the specific tree is can help narrow down which it is.
Acer Rubrum first, trident second, amur third: