The amazing part of that picture is that the trunk is intact. How can a fire be burning inside a tree trunk without first burning the bark?
PHYSICS.
The outer layer of the tree, especially one as beautifully majestic as this one has a strong layer of cambium just under the bark layer. The cambium is fluid. Before the cambium/bark burns in such an inferno, it has to first boil to reach the temperature where it will meet the temperature of the burning WOOD of the tree. The wood inside the tree is dry and lacking the kind of moisture of the cambium/bark.
An inferno like this where the wood is burning white-hot will cause the cambium to boil, expanding the fluid in the cambium hence exploding the cambium/bark layer.
Don't ever, ever, ever go into or near a burning inferno like this. It is extremely dangerous. I am sure fires fighters can tell stories of "popping noises" while the fire is being extinguished. Those noises are either exploding trees or imploding trees if they are cooled down quickly with water or retardants.
Leave the fire fighting to the people who know their business. Even they get trapped by wind and the unforgiving nature of fire and it's the ability to create it's own weather.