(Schwandt and Zack 1996). Unfortunately, 

 western white pine are also very susceptible 

 to attack by the mountain pine beetle, even 

 when they exist as relatively isolated 

 individuals or small groups in mixed-conifer 

 stands; damage is chronic in the Inland 

 Empire. 



• Mountain pine beetle 



Mountain pine beetle is a native North 

 American bark beetle with 4 major hosts, one 

 being western white pine {Amman et al. 

 1989). Historically, when extensive stands of 

 mature western white pine still existed, 

 mountain pine beetle outbreaks could kill a 

 large majority of trees just as mountain pine 

 beetles do today in extensive stands of 

 lodgepole pine {Pinus contorta). The 

 occurrence of pitch tubes along the bole is 

 one way to determine if attacks by mountian 

 pine beetles have occurred. Pitch tubes on 

 successfully attacked trees are generally very 

 numerous, 1/4 to 1/2 inch in diameter, and 

 consist of cream- to dark-red-colored masses 

 of resin mixed with frass. Pitch tubes on 

 unsuccessfully attacked trees are widely 

 scattered over the bole of the tree, 3/4 to 1 

 inch in diameter, and mostly cream-colored. 

 Confirmation of mountain pine beetle attacks 

 can be done by looking for the characteristic 

 gallery patterns on the inner side of the bark. 

 Bark beetles attacking western white pine 

 also introduce aggressive blue-stain fungi 

 that grow into the sapwood and contribute to 

 the death of the tree. 



Mountain pine beetles have 1 generation per 

 year, sometimes lasting longer at higher 

 elevations. The beetles overwinter mostly as 

 larvae within the egg galleries, then maturate 

 and emerge as adults to attack more trees 

 from June through August. The foliage of 

 trees that have been successfully attacked 

 during the current year can change color 

 anywhere from a few months to a year later. 

 Therefore, mountain pine beetle brood trees 

 attacked the previous summer and removed 

 during late-winter or spring salvage 

 operations may still have green foliage. 



• Pir Engraver 



The fir engraver is a wide-ranging bark beetle 

 in the western United States that has grand fir 

 as one of its primary host species (JFeneW 

 1986). For the past several years, the fir 



engraver has been killing grand fir in Swan 

 Valley at levels not seen for decades (Steve 

 Kohler, DNRC forest entomologist [retired], 

 personal communication). Nonoutbreak 

 populations of fir engraver beetle are closely 

 associated with trees affected by root disease 

 or other localized factors that stress trees 

 (Goheen and Hansen 1993). They can attack 

 vigorous trees, but often only damaging 

 instead of killing them (Ferrell 1986). 

 However, when grand fir become stressed 

 during periods of severe drought, such as 

 that occurring for several years prior to 2004 

 in western Montana, the fir engraver can 

 begin killing trees across a landscape, and 

 the association with localized stress factors, 

 such as root disease, becomes much less 

 distinct {Goheen and Hansen 1993). 



Management of the fir engraver is 

 problematic. In general, silvicultural practices 

 that promote the vigor of grand fir stands, 

 thinning, for example, will also reduce the 

 chances of extensive damage during periods 

 of drought {Ferrell 1986). Management 

 practices aimed at reducing the impact of root 

 disease will also help lessen the long-term 

 impacts of the fir engraver. Such practices 

 include the promotion of less root-disease- 

 susceptible species, such as western larch, 

 western white pine, and ponderosa pine, in 

 areas with extensive root disease. 



Indian Paint Fungus 



Indian paint fungus, so called because Native 

 Americans used the interior of the fruiting 

 body to make pigment, is a true heartrot that 

 very commonly infects true firs and hemlocks. 

 It is the predominant cause of heartrot and 

 volume losses in these species in western 

 North America {Hansen and Lewis 1997). 

 True heartrots are generally confined to the 

 heartwood of trees, consistently produce 

 fruiting bodies or conks on the stems of living 

 trees, and do not rely on mechanical 

 wounding as their principal infection court 

 {Etheridge and Hunt 1978). Large diameter 

 grand fir with decay caused by Indian paint 

 fungus provide important habitat, both when 

 standing and downed, for various species of 

 cavity-nesting birds and mammals {Bull et al. 

 1997). 



Echinodontium tinctorium spores infect trees 

 via the exposed stubs of small, broken-off 



Page D-4 



Forest Insect and Disease Report 



