fir engraver, spruce beetle, and root diseases. Fire problems 

 have increased due to the many dead trees. The probability of 

 high-intensity catastrophic fires, which would be extremely 

 difficult to prevent or control, has greatly increased, hicreased 

 wildfire suppression costs have occurred and will likely continue, 

 and suppression of western spruce budworm outbreaks has 

 been necessaiy in some high-value areas. 



In this forest type, as well as many other forest types in the West, 

 past har\esting practices and successful fire control have also led 

 to increased dwarf mistletoe problems. Harxesting practices that 

 left infected trees have led to perpetuation and intensification 

 of this disease problem (Hawksworth 1958 and 1961). Wildfires 

 were a primary factor in determining the abimdance and 

 intensity of the dwarf mistletoes and tended to keep them in 

 check. With successful fire control, the area affected and intensity 

 of infection have increased (Alexander and Hawksworth 1975). 



Many younger ponderosa pine stands in Oregon, Idaho, and 

 elsewhere are overstocked and susceptible to drought and bark 

 beetles. Many of these stands have been badlv damaged dining 

 the recent drought. 



WESTERN W^HITE PINE TVPE 



White pine blister rust, an introduced disease, has destroved 

 much of the valuable western white pine resource. In manv 

 places, western white pine has been replaced with true firs and 

 Douglas-fir, which are susceptible to drought, pests, and wildfire 

 (Monnig and Byler 1992). Serious root disease problems are 

 occurring in many of the areas where true firs and Douglas-fir 

 replaced western white pine, and these problems are expected 

 to continue. 



LODGEPOLE PINE TYPE 



Some lodgepole pine is dependent on fires to heat and open its 

 cones so that seeds are released. Historically, mountain pine 

 beetle outbreaks were followed by large high-intensit)' wildfires 

 that released the seeds to start a new stand. In recent decades, 

 large areas of the lodgepole pine type reached a size and condi- 

 tion vulnerable to the mountain pine beetle and were attacked 

 and killed. Because of fire control, lodgepole has had difficulty 

 perpetuating itself on some sites and in some cases is being re- 

 placed by the true firs and Douglas-fir, which are highly suscepti- 

 ble to drought, pests, and wildfire (Monnig and Byler 1992). 



10 Forest Health Concerns 



