I’m not too picky. Dead and down with a good dry “snap” to it is good.  Mostly I use breaking size wood with a few sawn wrist size pieces. I use the homemade egg carton/dryer lint/wax firestarters.  I just light the candle and let the wax drop onto the lint.

I see that beaver wood is mentioned.  I don’t know about the Q, but the BW frowns on its use … to the point where you could get ticketed. From page 2 of the BWCA Rules and Regulations under “Campfires”,   (You need to Login or Register  “When making a fire only use dead wood found lying on the ground; collect it away from campsites, portages, and shorelines to prevent enlarging and defacing these areas.” Rangers will interpret driftwood, as well as beaver wood and overhangs falling under this rule.

In their “Angler Ethics” brochure,   (You need to Login or Register , they spell it out better. Page 3, Item #4 Minimize Campfire Impacts: “Don't use driftwood, snags arching over water, or wood from beaver dams and lodges.”

I'm sure three are other references.