Not if you are looking at mitigating heat in cities. A 6ft tree will be giving a decent amount of shade after 5 years' growth if you pick the right species. The trick is looking after them.
What does it matter whether it was a lab leak or zoonotic transmission at this point?
Well, possibly quite important if you want to assess the risk posed by wet markets. And if it was a lab leak (personally, I think less likely) you'd want to know where processes failed, and possibly some heads to roll.
An explanation of how this works from the article:
JWST is able to analyse the light that passes through the faraway planet's atmosphere. That light contains the chemical signature of molecules in its atmosphere. The details can be deciphered by splitting the light into its constituent frequencies - rather like a prism creating a rainbow spectrum. If parts of the resulting spectrum are missing, it has been absorbed by chemicals in the planet's atmosphere, enabling researchers to discover its composition.
Note that they say the identification is ‘tentative’ and not robust yet.