Found this fallen Poplar tree while out walking.
The bark is also good to burn as it burns slowly, smouldering rather than flaming and gives off a a lot of heat (the end of a long piece can be placed in a fire and once smouldering, used to carry fire with you).
To make a fire for a brew, I collected a hand full of damp leaves from the ground and rubbed them vigorously between my hands to break down the fibres and remove moisture. I placed these on the ground and using flint and steel, sparked onto a piece of Crampball fungus and once glowing, placed it on the leaves. I then placed another handful of buffed leaves on top leaving a small cavity around the fungus. By gently blowing, the glowing Crampball produces heat and the cavity acts like an oven to hold heat and gradually remove moisture from the leaves. Eventually the leaves will dry sufficiently for a flame to appear.
Here is a rather nice example I found on another website.