Hello!

My name is Andrea and I just joined this forum! I am fairly new to bonsai care and had a question concerning my bonsai. My bonsai had recently gone through a lot. It was losing a ton of leaves and I had no idea what to do. I should mention that I live in Canada and I believe the climate had to do with this. Recently the leaves have begun growing back and the bonsai is looking well, though none of the leaves have begun growing on the back branches of the tree. Is it safe to assume that the back branches are dead? Should I trim them off? Also, is there anything else I could do to aid in my bonsais regrowth? I attached some pictures of bonsai from before the leaf fall-out and after for reference.

Thank you!

I do want to mention that this is a bonsai purchased from Costco and I know it's bound to have its issues. Regardless, I still want to take care of it well as it is still a plant of mine

Hello and welcome.

Well, first of all, this is by most not considered a bonsai. It's a mass produced ficus, the branches of one type grafted on the roots of another.
The only thing it has to do with bonsai really is the label, and that is only for commercial purposes. So, treat it as any other houseplant/ficus and it will do fine.

lucR wrote: the branches of one type grafted on the roots of another.

Like lucR said, the branches are grafted on a understock of a other tree. The graft with small leaves died.
The understock roots of a other ficus is still alive, but that will push out bigger and bigger leaves.
If you don't mind the bigger leaves, then go ahead and grow it that way. Then you can remove the dead branches.
If you don't like that foilage. Buy a new one, as there not expencive.

Thank you so much for your help! I was a bit confused with the idea of branches being grafted onto another tree, but your message had cleared this up for me! I'll take your suggestions into consideration. Thank you so much again!