yea, it's interesting because there are lots of anecdotes about trees exploding but I don't think they explode, especially in a technical sense- this arborist and this article are one of the top hits on exploding trees. explosives are more about brisance which is a measure of the velocity of the expanding gasses. it makes intuitive sense that there are high internal stresses within a large tree like this that might cause rapid stress propagation with variations in energy input(extreme cold or hot, just like other brittle materials- glass porcelain etc.), but compressed cellulose isn't an explosive. it's more like a high-tension cable snapping. there is still a tremendous amount of potential energy released in a short time(someone said 15 tons!), but it isn't an explosion. anyways, who cares? try and bring up brisance when people talk about the exploding tree at a party and watch their eyes instantly gloss over. just let the beautiful people have fun on TV.