Article ends with:

There was no independent verification of the surgeon’s claims.

The internet tells me that “plant growth requirements” are air, water, nutrients, space, and light.

Let’s imagine. The growing plant was found in a lung. It must have:

Air. Plants ingest carbon dioxide, exude oxygen. Both gasses are present in our own respiration. So that checks out.

Water. I guess water was leeched from the lungs’ blood supply, since we’re all just bags of mostly water.

Nutrients. See water, above. If the mamallian reproduction system can supply a growing embryo with required nutrients, why not those required by a fir sapling? Sure, they’re different requirements, but press on.

Space. Assuming that no other competing species of plant is growing in the lung, this isn’t a problematic issue.

Light. Ah, well. Photosynthesis requires sunlight, and I am reminded of a joke attributed to Groucho Marx, Abraham Lincoln, Nicola Tesla, and Albert Einstein:

Outside of a dog, a book is a man’s best friend. Inside of a dog, it’s too dark to read, or to cultivate horticulture.

I am as dubious of this fir sapling story as my quoted joke’s provenance.