Deep in my Slumber <<< Riddle poem

Deep in my slumber
you rise tall above me
like a great tree above the land

You protect me from dangers
and ward off the evils
whose hisses and howls
wish to stir me from my solitude

You are my towering soldier
Spreading the word of my story
for all the world to see

While I'm deep asleep
in my grave

do you know what it is ?