Read the article. Yeah, this is just silly. It's basically DIY (do it yourself) Vicks Vaporub which can, yes, make you feel better if you have a chest infection but it's only relieving symptoms such as sore throat, cough (which, by the way, we're SUPPOSED to cough; it's ridiculous to suppress a cough when you have a bunch of junk in your lungs that needs to get out), airway constriction, etc.
Let's look at this logically from the perspective of a CF patient: most CFers have PA colonization. Breathing a VERY dilute vapor (you aren't even nebulizing it; you're just relying on natural steam action which doesn't make properly sized particles to penetrate deep into the lungs anyway) is not going to kill Pseudomonas (one of the hardiest bacterias out there) and your odds go down even further if you have Cepacia or something (which is so hardy it can live in disinfectant and betadine). Pseudomonas doesn't even attack trees, so trees would have no reason to evolve a defense against PA attacks. If all it took to fix CF exacerbations was tree oil, don't you think medical scientists would have explored that option? There isn't some international conspiracy that revolves around forcing us to take antibiotics and suppressing "natural" remedies - the reality of it is, natural remedies often just don't work or only treat some of the symptoms if they do anything at all rather than the underlying problems.
For example, Vicks Vapo Rub might make you feel better if you have a chest cold, but it's your body's immune system that kills the viruses. Vicks just alleviates some of the common symptoms without actually doing anything at all to resolve the underlying issue.