I know EXACTLY what caused these fires. The pine beetles have been killing trees in colorado and southern Wyoming for several years now resulting in huge swaths of dead pine trees. NONE of these trees can be harvested for lumber. The only way to properly manage this problem is to take the infected and dead trees, put them in a pile and burn them. Since we haven't done that nature has decided to do that for itself.
Furthermore why the heck does the forest service even need this stuff? Wouldn't it be better for the much better funded military to have these tank vehicles given that not only do they have the cash but they would also have more use given that being able to put out fires in other countries might come in handy for the army.