How to add a column distinguishing which data fall in which buffer?

Question

I have a database with trees, and certain trees are the 'key' trees. I filtered the rest of my data so that I am only looking at the portion of (non-key) trees that fall within a 100m radius (buffer) of the key tree.

I want to export this new dataset so I can run some analyses. However, when I export it, there is no indication as to which datapoints fall within which buffers - this is necessary as I will be analysing the buffers separately.

How do I label each buffer with a unique ID that the datapoints will correspond to within the attribute table?

Answer 1

Ah I figured it out - when I do 'extract by location', there is an option to "iterate over this layer" (green recycling symbol) - this generates a new extracted output for each buffer.