The top one is a field buttercup, the lower one a birch tree. The buttercup can be invasive and the birch can quickly grow into a large tree.

The first one is a buttercup - dunno about the second.

the first one is definatly a butter cup and bulbaholic is right it is very invasive spreads like wild fire. the second I agree looks like a birch.
I must say I prefer trees that are going to give something back my self like apples pear etc.