rick like justin said cedar bark is the best. its good you are doing it with local material. you should continue to experiment with different materials. theres a lot of stuff that works as an extender and as tinder. cattail down is one of the best extenders there is . dried up tree mushrooms are great as well as the pollen inside puffballs.. for tinder grass , leaves , pine needles milkweed down, thistle down, phragmites heads. inner barks from basswood, blacklocust, tulip, and so on. like you already know birch is highly flammable once you have ignition itll burn even in the pouring rain because of the wintergreen oils. keep trying . once you get it in your head you'll just see things that work. walking in the woods has become a trip to the store. i earmark plants, trees , everything. was camping in new yourk when somebody cut themselves pretty bad. the catalog in my head opened and i ran to grab plantain and yarrow. one to stop the bleeding the other to heal. i just remembered seeing the stuff so was able to put it together before the first aid kit came out. keep playing brother