What are these trees that grew on their own?

[Suhan]

Can you help identify these trees? Are they weeds? I’ve been getting lots of pests on my other plants so wanting to know if these trees are the cause.

 

[Suhan]

 

[cpp gardener]

Can you post some close-up pictures of individual leaves, twigs, flowers and fruits (if there are any) and the main trunk? I have some ideas, but I need more info and controlling each can be very different.
As far as ‘weeds’ go, if you didn’t plant it and don’t like it, it’s a weed.