Not exactly but your on the right track. Spanish cedar offers the following advantages.
First and most importantly it offers protection from tobacco worms – through the cedar’s special odoriferous quality
Secondly, it has high humidity absorption capacity – this ensures that a stable climate will be maintained inside the humidor and mold is prevented. In simple English it has the ability to absorb AND reject humidity just like a humidifying propylene glycol element.
These two things properly support the cigar aging process.
The cedar also has a positive effect on the*flavor of the cigars due to it's very neutral scent. "Strong" American and Canadian cedar has a very powerful scent and is not the best liner for humidors. If provides the same protection and humidity advantages as Spanish cedar but imparts too much flavor into the cigars. Most cheaper humidors have American cedar in them. If your serious enough about cigars too buy a box or more your serious enough to demand Spanish cedar.
Sorry to be super anal about the matter but I like cigars and reps about the same.