I’ve got tree planting list across multiple sheets e.g.,

I’m trying to create a summary sheet whereby you can select projects (i.e., sheets) from a dropdown list and that will automatically generate a list of species and there totals. I’ve managed to do one for all the projects, but ideally would like one that has selected projects on.

I think I’ve figured out how to get the totals (colB) using:

=SUMPRODUCT(SUMIF(INDIRECT("'"&SheetList&"'!"&"A2:A100"),A2,INDIRECT("'"&SheetList&"'!"&"D2:D100")))

However, I cannot figure out how to get a list of unqiue trees species from the selected sheets. I’ve tried:

=UNIQUE(FILTER(VSTACK(INDIRECT("'"&SheetList&"'!"&"A2:A50")),VSTACK(INDIRECT("'"&SheetList&"'!"&"A2:A50"))<>""))

But this doesn’t seem to work.

Here is a link to my sheet.
https://easyupload.io/dyc7ne