Royal empress tree
One thing you should know is that the Pawlonia or Empress Tree is considered an invasive plant in Oregon. It can reseed itself into our native area landscapes and dominate native plants. Be vigilant to remove any new seedlings you find. I would encourage you to remove it but I hesitate to try to make it grow better with more pruning or fertilization. Any tree that is making weak growth is normally helped by pruning back leggy limbs and improving the soil around it. Think about removing it, especially if you start finding seedlings.
I know royal empress is supposed to be invasive so I'm keeping an eye on it we have three acres and I check periodically for new trees so far nothing my question of the flower buds in the fall and why I don't get flowers in the spring also the pruning to thicken up the shade area