Identification through the seasons

I started studying trees in summer, and it seemed the main way to identify them was by their leaves.  I knew that people did identification by winter twigs, but that seemed hard, so I thought summer was really the main time you can identify trees, and the rest of the time, it's like going blind.  But it turns out that fall and spring bring whole new worlds.

Last summer, I was still learning the difference between sugar maple and Norway maple.  I knew that bark was different, but I didn't know if my hypotheses based on bark were correct.  When fall came, I could easily tell sugar and Norway maples apart -- sugar maples were colorful while Norway maples were green, then sugar maples were losing their leaves while Norway maples were yellow.  When these trees gave away their identities in fall, I then came to know which was which, and thus could see which bark was which, so now I can be more confident in my identifications based on bark.

Now has come spring.  Silver maples have opened their buds to red-brown flowers, and red maples have partially open red buds.  Norway and sugar maple buds are maybe swelling a little, but not doing a lot.  So now, I can easily distinguish certain trees by their buds.  In a cluster of silver maples, I saw one tree that had the same bark as the others, but just closed buds, so I figured it was not a silver maple but an old sugar maple.  And as I walked along looking at the saplings alongside EMPAC, I hypothesized that they were sugar maples.