Five-needle pines are 

 important trees in south- 

 western Oregon. West- 

 ern white pine and sugar 

 pine are valuable be- 

 cause of their fast 

 growth, ability to reach 

 great ages and sizes, frost 

 hardiness, and resis- 

 tance to root disease. All 

 three species have high 

 scenic, wildlife, and wa- 

 tershed values. They 

 contribute significantly 

 to ecological diversity. In 

 the absence of blister 

 rust and mountain pine 

 beetle, these pines thrive. 



Sugar Pine, Western White Pine, 

 and Whitebark Pine Mortality 



6.000 



E-D 



1.200 

 1.000 

 800 

 600 

 400 

 200 



5,000 

 4,000 

 3,000 

 2,000 

 1,000 



Year 



Ponderosa Pine, Douglas-fir, 

 and White Fir Mortality 



q u 3 



o.o 

 > = 



E 



70,000 



60,000 ; 



50.000 I 



40.000 : 



t 



30.000 I 



20.000 ; 



I. 



10.000 

 



Year 



Losses offve-needle pines has 

 been greatest in southwestern 

 Oregon between 1 988 and 1991. 

 a period of severe drought 



Source: Cooperative Aerial Survey, Oregon 

 Department of Forestry and USD A Forest Service. 



Mixed Conifers 



Bark beetle mortal- 

 ity is highest on dry, 

 overstocked sites — ^Ponderosa pine, Douglas- 

 fir, and white fir mortality from bark beetles 

 was particularly high in 1995, especially on 

 dry, overstocked sites. Currently, drought and 

 insects are replacing fire as primary regulators 

 of site stocking. Such uncontrolled distur- 

 bances have serious drawbacks. For example, 

 large ponderosa pines tend to be the first trees 

 killed by bark beetles; such large trees are of- 

 ten important to meet management objectives. 

 Extensive insect-caused tree mortality, par- 

 ticularly in multilayered stands, can create 

 massive fuel buildups, which ultimately can 

 contribute to large-scale, severe wildfires. 



Landscape-scale assessment is becoming in- 

 creasingly common for addressing drought-re- 

 lated mortality issues. Density-management 

 projects are planned or underway in many over- 

 stocked stands. Treatments include thinning, 

 prescribed burning, or a combination of the two. 

 Treatment priorities are assigned by risk-rating 

 systems that take into consideration stocking, 

 elevation, proximity of insect activity, the urban- 

 forest interface, and fire regimes. 



Bark beetle mortality in south- 

 western Oregon has been high 

 since the late 1 980s. The preva- 

 lence of dense stands over ex- 

 tensive areas and a succession 

 of extremely dry years have pre- 

 disposed trees to insect attack. 



Source: Cooperative Aerial Survey, Oregon 

 Department of Forestry and USDA Forest Service. 



Locations of bark beetle mortality in all tree 

 species on the Rogue River National Forest and 

 Bureau of Land Management's Medford District 



in I 995. Source: Cooperative Aerial Survey, Oregon Department of 

 Forestry and USDA Forest Service. 



Oregon — 43 



