It is now no longer possible to burn your tree cuttings/dead plants etc.
A new law was passed earlier this year https://www.boe.es/buscar/act.php?id=BOE-A-2022-5809 that is intended to create a 'Circular economy' but has been very badly conceived.

More details can be found here: https://revistajaraysedal.es/quemas-vegetales-denuncia-asaja/#:~:text=ley%20de%2... or search for 'prohibido quemar restos vegetales'

The town halls will obviously not be issuing burning licenses.

It is possible this will change in the near future as it is really unworkable but at the moment it is in force.