I wonder - are these pine forests man-planted for commercial use?
I wonder if a living forest has to have a diversity of species for a balanced symbiotic relationship
so that the range of insects and predators can keep fatal infestations at bay?
FIRE! Another option for pest control has always been the use of low-level, small controlled burning. Not only does this open space up for sunlight and air, encouraging predator birds such as the woodpecker and other insect-eaters, but it safeguards against wild-fire which in dense pine forests quickly gets out of control.
"Many of the sites have grown so dense that fire would be uncontrollable. Significant damage to watershed and resources would occur.
In these areas, mechanical treatments such as thinning may be needed to reduce the amount of fuels before burning. This would increase the success of subsequent prescribed fire treatments in restoring these forests to their historical conditions. Forests would be more open and savannah or park-like, with well-spaced, large-diameter trees dominating a grass under story. These forests would allow for low-intensity fire to occur. In addition, they would be much more resistant to attacks from the mountain pine beetles."
(Look at the Tree behind these gallant fire-fighters!!)