Awe come on now Ike, don't take it too hard, besides if you ever stood next to one of the saquaro catcus you would know it's as big as an oak or maple tree. They don't grow their first lim until about the age of 70 and the insides are made up of bamboo like tubes which I would call wood. Many people in the desert use the skelletons for yard art. And believe me the thorns on those are like needles and are very hard. FYI, the barrel catcus is what you look for if you need water for survival, but it is very bitter.
So cactus tree for non-desert people, it's ok to call it a tree, after all they do bloom in the spring.