Out here in the forest you can keep the fire going a good four or five hours just putting bigger chunks of wood on. The embers stay good long enough to get chores done. If you were really worried about it, you could pile a heap of old fir cones on the embers and let them smolder all day, or old elk or cow droppings if you can find any.

For travel, a good leaf bundle is pretty handy. Grass will work too, but you have to bundle it tight and be able to stick an ember down in the center. Again, bovine dung also smolders along well, as do old fir cones.

I also like to collect coniferous pitch/resin from trees when out and about. It makes a handy fire aid for all kinds of things. For instance, drop an ember in a small amount of pitch, give er a blow or two, and instant flame on.