There is dry rot wood, dead wood and punk. Dry rot wood is wood inside a dead tree, light weight, dry, crumples in your hand. dead wood might be a dead branch that snaps in two easily. punk is in a dead tree trunk and is resilient or spongy. You can depress it and it bounces back. Not all dead wood is punk. You can char punk and it will work but punk untreated will hold an ember. You can create the ember with flint and steel or a magnifying glass.