Crown fires tend to be more beneficial in ponderosa pine forests because they stay close to the ground, burn relatively cool, and clean up forest debris to give the trees a quick burst of nutrients?

The statement above is TRUE. 
The effects of accident fire on Ponderosa pine forest is usually devastating because of the denseness of the forest, because of this controlled fire is usually used to thin down the forest in order to avoid fire incident. The controlled fire used is usually beneficial to the forest and enhance the fertility of the soil.