United States 

Department of 

Agriculture 

Forest 

Service 

Northern 

Region 

200 East Broadway 

P.O. Box 7669 

Missoula, MT 59807 

Numbered Report 06-05 March 2006

Mapping Mountain Pine Beetle and White Pine Blister Rust in White Bark 

Pine on the Helena National Forest 

Nancy Sturdevant , Entomologist 

USDA Forest Service, Forest Health Protection 

Missoula Field Office 

Sandra Kegley, Entomologist 

USDA Forest Service, Northern Region Coeur d’Alene 

Introduction 

Mountain pine beetle, Dendroctonus ponderosae

Hopkins, (MPB) populations have been 

increasing in Montana over the past ten years, 

with outbreaks in all host species extending to 

one million acres in the Northern Region. 

Unusually high levels of MPB caused mortality 

of whitebark pine (WBP), totaling 143,000 acres 

were recorded in 2005 in the Region. More than 

8,600 acres with WBP mortality were recorded 

on the Helena National Forest (NF) in 2005. 

During July and August 2005, we assisted the 

Helena NF map mortality of WBP in 32 stands 

on the Townsend Ranger District (RD). The 

areas we evaluated were Edith Peak, Baldy 

Mountain, and Occidental Mountain-Bluebird 

Meadow. We conducted walk-through surveys 

to maximize the number of stands evaluated. 

Our objectives were: 1) to provide training and 

assistance in identifying tree mortality from 

MPB and white pine blister rust, Cronartium 

ribicola Fisch, and 2) to evaluate mortality in 

WBP from MPB. We also noted the presence or 

absence of white pine blister rust in stands 

evaluated. 

Methods 

Stands were selected for mapping beetle-caused 

mortality from different compartments for three 

geographic areas: Edith Peak, Baldy Mountain, 

and Occidental Mountain-Bluebird Meadow. 

Stands within compartments were selected that 

were close to roads or trail systems. A few 

stands were also selected that were located in the 

center of compartments to represent variation in 

beetle and stand conditions. 

The approximate center for each stand was 

located using landmarks and topography from 

stand compartment maps. Starting at the center 

point, a walk-through survey was conducted to 

estimate WBP mortality and other stand 

parameters. This was done by walking several 

transects radiating from the center to the stand 

perimeter and noting information on the 

following parameters: 1) stand compositionWBP versus WBP as a component of a two or 

three species stands, 2) an ocular estimate of % 
2 

mortality of whitebark pine, 3) presence/absence 

of mountain pine beetle, 4) presence/absence of 

blister rust on white bark pine, and 6) remarks on 

the regeneration, including trees per acre by 

species or only as presence or absence of 

regeneration by species. Blister rust was rated 

only as present or absent with no severity 

recorded. We did not include trees in the WBP 

mortality estimate that had been dead a very long 

time as evidenced by the lack of bark.. 

The definition of a WBP stand for this effort was 

one that comprised >60% of the total trees per 

acre > 5 inches DBH in WBP. Two-species 

stands are defined as ones in which two species 

dominated more than 80% of total trees per acre 

greater than 5 inches DBH. Three species stands 

are defined as those where three species were 

dominant. 

In addition to providing assistance with the 

mapping survey, we also established a series of 

FINDIT plots (Bentz 2000) near Edith Peak to 

evaluate trends in MPB activity. Seventeen 

variable radius (BAF 10) plots were established 

at three chain intervals in two areas near Edith 

Peak; the southeast side of Edith Peak (7 plots) 

and along the trail going towards Edith Lake (10 

plots). 

Table 1. Stands mapped on Edith Peak. 

Stand ID Species 

Composition 

%Mortality 

of WBP 

White 

Pine 

Blister 

Rust 

(P/A) 

Moun

tain 

Pine 

Beetle 

(P/A) 

Regeneration 

TPA 

12302061 WBP 90 P P 0 

12302057 SAF/LP/WBP 60 P P SAF-88 

12302061 LP/SAF/WBP 90 P P -- 

12302051 LP/WBP 65 P P SAF-200 

12302042 LP/WBP 25 P P SAF-400 

12302043 LP/WBP 15 P P SAF-600;WBP500 

12302052 WBP/LP/SAF 95 P P SAF 

12202059 WBP 50 P A WBP-300 

12202042 WBP 50 P P WBP-300 

12202039 WBP 0 P P WBP-300 

12202017 LP 0 A A LP 

12202016 LP 0 A A WBP-400 

12202153 WBP 10 P A WBP-1000 

12202035 WBP 60 P A SAF-WBP-450 

12302032 SAF/LP 1 P P SAF-88 

14303010 WBP 60 P P SAF/WBP-400 
3 

Table 2. Stands mapped on Occidental Mountain-Bluebird Meadow. 

Stand ID Species 

Composition 

%Mortality 

of WBP 

White 

Pine 

Blister 

Rust 

(P/A) 

Mountain 

Pine 

Beetle 

(P/A) 

Regeneration 

TPA 

32303033 LP/SAF/WBP 5 P A SAF-WBP-450 

32303083 LP/SAF 1 P P SAF/LP 

32303034 WBP/SAF 20 P P WBP/SAF-1300 

32303020 LP 5 P A SAF/DF/WBP/LP2800 

32303013 WBP/LP 5 P A SAF/DF-6400 

32303057 LP 5 P A WBP 

32303064 LP 50 P P WBP 

32303063 LP 50 P P WBP 

32303058 LP 25 P P WBP 

32303040 LP 25 P A WBP 

32303032 LP 25 P A WBP 

32303050 LP 25 P A WBP 

Table 3. Stands mapped on Baldy Mountain. 

Stand ID Species 

Composition 

%Mortality 

of WBP 

White 

Pine 

Blister 

Rust 

(P/A) 

Mountain 

Pine 

Beetle 

(P/A) 

Regeneration

TPA 

13403021 WBP 20 P P WBP/SAF/ES

13403012 WBP 50 P P WBP/SAF500 

13403016 LP/WBP 30 P P SAF/WBP7100 

13403015 LP/WBP 1 P P WBP/SAF2200 
4 

Table 4. MPB in WBP in vicinity of Edith Peak (FINDIT plot data): 

Area Green 

Trees per 

Acre 

’05 

Attacks 

per Acre 

’04 

Attacks 

per Acre 

Older 

Dead 

per Acre 

Total 

Dead 

per Acre 

% of 

stand 

killed to 

date 

Edith Peak 

(7 plots) 

107 32 82 103 185 72% 

Edith 

Lake Trail 

(10 plots) 

118 11 17 42 59 44% 

Mortality from Mountain Pine Beetle and 

White Pine Blister Rust 

Although there are stands in all three areas 

surveyed where almost all WBP has been killed 

by beetles, there are others with little beetlecaused mortality. Mortality of WBP on Edith 

Peak ranged between 0 and 95%; and 5 and 50% 

and 1 and 50% on Occidental and Baldy 

mountains, respectively (Tables 1-3). MPB was 

present in 20 out of 32 stands surveyed and was 

found attacking both WBP and lodgepole pine. 

Beetle-caused mortality was higher on Edith 

Peak than on Occidental and Baldy mountains. 

In all three areas surveyed, recent mortality from 

MPB occurred within the past three years, with 

the majority occurring in 2004. There was also 

beetle-caused mortality in all three areas that 

probably occurred sometime during the 1950s or 

earlier. 

Similar to the results from the mapping survey, 

FINDITS showed stands near the peak of Edith 

Mountain had the highest mortality from MPB 

(Table 4). Stands surveyed along the trail still 

have a high number of attacked trees per acre, 

but this number has been also declining over the 

past few years. To date, 44% of trees in stands 

near the trail and 72% of trees in stands near 

Edith Peak have been killed by MPB. Both 

numbers will most likely be higher at the end of 

the outbreak because there are still green trees 

available and the remaining stands are still 

susceptible to beetle attack. Beetle-caused 

mortality in both areas is declining due to host 

depletion. 

In the stands surveyed, 30 out of 32 stands had 

evidence of blister rust. Damage from blister 

rust was most severe on Edith Peak. We 

observed significant top-kill in mature trees from 

blister rust in stands in all three areas surveyed. 

Because of this we expect less WBP cone and 

seed production in the future in these stands. We 

also found a few dead trees that were not killed 

by MPB but we suspected were killed by blister 

rust. In the Occidental Mountain area, there 

were considerable numbers of sapling and pole 

size WBP with limited amounts of blister rust. 

We recorded WBP regeneration in almost all of 

the stands surveyed. However, many of the 

stands also had a healthy and large component of 

subalpine fir seedling and advanced 

regeneration. Without management intervention 

to reduce competition from subalpine fir, the 

potential of WBP to survive may be 

compromised. 

Conclusions 

Many of the stands we surveyed did not 

resemble the typical spreading canopies and the 

majestic, wind-battered growth forms of WBP 

that are common in upper subalpine fir zones. 

Instead, they phenotypically resembled more 

densely stocked, mixed lodgepole pine stands 

that are found in those same zones. 

In areas where fire suppression has resulted in an 

abundance of late-successional forests, 

susceptibility of both lodgepole and WBP to 
5 

MPB has increased. In these densely stocked 

stands, WBP is likely to be attacked by MPB 

because of stress from competition with 

subalpine fir. The absence of fire also leads to 

increasing age of the lodgepole and whitebark 

component which further escalates their 

susceptibility to MPB infestations (Tomback et 

al. 2001; Marsden 1983; McGregor & Cole 

1985). 

There are several silvicultural and prescribed fire 

techniques to manage whitebark pine at the stand 

and landscape level that have been little tested. 

These include techniques such as thinning and 

removing the subapline fir component, to reduce 

competition and stress and increase openings 

necessary for whitebark pine regeneration. 

Incorporating fire, either prescribed or wildland 

fire use, can provide long-term benefits to WBP 

survival if planned and implemented properly 

with well-described objectives and prescriptions. 

Thinning from below to 80 square feet of basal 

area is a very effective silvicultural technique 

that reduces lodgepole and ponderosa pine stand 

susceptibility to MPB. Although this technique 

has been shown to reduce stand susceptibility of 

lodgepole pine to MPB, it has not been evaluated 

for WBP stands. Thinning from below may be a 

reasonable management strategy where there is a 

mix of lodgepole and WBP in a stand, or when 

WBP is growing in densely stocked stands to 

reduce the future activity of MPB. 

Other management techniques to reduce losses 

due to MPB incorporate the use of synthetic 

insect pheromones. Verbenone is an 

antiaggregant pheromone for MPB that has 

successfully protected WBP trees from attack 

(Kegley et al. 2003; Kegley and Gibson 2004). 

There are many examples of the use of 

verbenone to protect individual high- value WBP 

across the Region. Trees can also be protected 

from MPB attack by preventative applications of 

the chemical insecticide carbaryl. Carbaryl 

provides protection against MPB attacks for up 

to two years when it is properly applied. Either 

of these tools provide short-term protection 

during outbreak conditions, but do not provide 

the long-term protection as does vegetative 

management. 

Edith Peak is part of a proposed project area on 

the Townsend RD and would warrant evaluation 

as an area to treat, especially in stands that have 

limited MPB-caused mortality. Recent increases 

in precipitation will improve tree vigor and may 

lessen the magnitude of mortality from MPB 

over the next few years on the Helena NF. 

However, it may be several more years before 

MPB populations return to more endemic levels. 
6 

References 

Bentz, B. J. 2000. Forest insect and disease 

tally system (FINDIT) user manual. 

USDA Forest Service, Rocky Mountain 

Research Station. RMRS-GTR-49. 12 p.

Kegley, S., Gibson, K., Schwandt, J., and 

Marsden, M. 2003. A test of verbenone 

to protect individual whitebark pine from 

mountain pine beetle attack. USDA 

Forest Service, Forest Health Protection 

Report 03-9. 6 p. 

Kegley, S., and Gibson, K. 2004. Protecting 

whitebark pine trees from mountain pine 

beetle attack using verbenone. USDA 

Forest Service, Forest Health 

ProtectionReport 04-8. 4 p. 

 Marsden, M.A. 1983. Modeling the effect of 

wildfire frequency on forest structure and 

Succession in the northern Rocky 

Mountains. Journal of Environmental 

Management. 16:45-62. 

McGregor, M.D. and D.M. Cole. 1985. 

Integrating management strategies for the 

mountain pine beetle with multipleresource management of lodgepole 

pine.Forests. USDA Forest Service 

Intermountain Research Station, General 

Technical Report INT-174, Ogden Utah. 

Shore, T.L. and Safranyik, L. 1992. 

Susceptibility and risk rating systems for 

the mountain pine beetle in lodgepole 

pine stands. Information Report BC-X336. Victoria, B.C. Forestry Canada, 

Pacific and Yukon Region, Pacific 

Forestry Centre. 12 p. 

Tomback, D.F., Arno S.F. and R.E. Keane 

(Editors). 2001. Whitebark pine 

communities, ecology and restoration. 

Washington D.C.; Island Press. 440