Oak and all in the deciduous family(To my knowledge) except the black elm can be used as skewers. Pine is fine, too(There are some myths to the contrary) but it leaves a sticky film on your foodstuffs. Technically, oak leaves and acorns are toxic to your kidneys, but you have to REALLY eat them- we're talking like a whole tree at once- to hurt you.

 

Pretty much most woods are good if natural. Not talking fence post or anything chemically treated. Poplar, willow, oak, pine, and cedar is especially good since it imparts a nice flavor. There are only a few that arent safe. I would concentrate on learning those oleander bushes, possibly black walnut and possibly pistachio and possibly cashew trees. Oleander is pretty toxic though from what I understand. Never personally tested it lol

 

I like hickory in GA. I eat acorns too. Twice boiled and drained pulverize into a paste fry like pancakes. Mostly White oak acorns though. Red oak acorns are bitter.