Cbd is really stable.
You had that backwards
But yea environment definitely plays a role. But choosing one cannabinoid or another is outside the realm of possibility without chems and gnarly ways...
Uv forms of potassium and phosphates increase terpene production along with cannabinoids.
Composting stems etc and re using dirt, tilling in root ball etc will help. Phenols can be present in the dirt a lil over a year.
The production of cannabinoids and terpenes are really only split through enzymes thc cbd cbc and the propyl, thcv cbcv etc come from this process.
All we can really do is help the plant produce more precursor compounds to get turned into these cannabinoids