Lancaster Ontario - Cooper Marsh OR Abject Ignorance...

Yesterday was a real summer day, sunny and warm with a gentle breeze. We spent the morning wandering through the Cooper Marsh Conservation Area near Lancaster, Ontario, and the afternoon at the pub.



Despite the distant hum of highway traffic in the distance, the walkways over the marsh and through the woods were quiet and peaceful, with only an occasional bird-call or cricket-chirp from the bushes and trees. Frogs rested in the deep grass. Here's one, the picture of relaxation:



Most places in the province of Quebec are named after saints; the most obscure and unidentifiable saints possible. For instance:

Saint Telesphore:



Saint Zotique and Saint Polycarpe:



Saint Clet:



Telesphore sounds especially mysterious to me; I hope he was an astronomer of some kind.

And now we come to the real moment of ignorance; if anyone can tell me what these trees are, I would be grateful and would try to lodge this information permanently in my brain.

First tree:





Second tree:



Third tree:



Fourth tree (birch?):



And a little yellow flower:



Thank you!