Various gum trees make for fairly decent fireword. Not as good as oak or hickory, but better than cottonwood pine or fir. Many species of gum are a pain to split, but once split burn OK.
Yes
Yes, it is safe to burn sassafras and it is commonly burned in many locales.
They provide a raised spot for the fire, letting ashes drop below, and providing air circulation for the wood to burn.
Yes it can
If you keep adding wood, no time limit. A low fire, green logs, banking the fire, a maximum of about 6 hours.
I do.
Yes
Check with Martin for an owner's manual. Unless a fireplace is specifically rated as multi-fuel, a gas fireplace cannot safely burn wood.
No, it is not safe to burn. It is toxic.
Yes.
No. It's illegal.
yes
yes
Its wood isn't it
Yes.
quite good to burn indeed!
Yes.