The best wood to burn is what you can get, On Mayday I went to a party and there was a lovely campfire made from Hornbeam, Lit up quite easy, very hot embers, flames to see by with each new log but if you're in a really big pine and spruce forest it could take over a day to get some ash or whatever you think would burn better. In that situation burn what's there rather than have a cold night and no warm food.