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Forest Health
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Numbered Report 10-01
JAN 2); 7 2010 Whee
Evaluation of verbenone treatments for the erecanticSeneo ve Of triountain pine beetle
(Dendroctonus ponderosae) attacks on lodgepole pine at Lookout Pass Ski and
Recreation Area 2003-2008
aSB608
Carol Randall, Entomologist
.L6R36
2010
USDA Forest Service, R-1 Forest Health Protection
Coeur d’Alene Field Office
EXECUTIVE SUMMARY
The forests in and around Lookout Pass Ski and application of 20 Beetle Block Verbenone
Recreation Area have a significant component of pouches per acre was made in early June. In
lodgepole pine (Pinus contorta) susceptible to 2008, one application of Pherotech Inc.’s 7-gram
mountain pine beetle (Dendroctonus verbenone pouch was made in early June.
ponderosae)(MPB) attack. Aerial Detection
Surveys (ADS) began to detect lodgepole pine During the June 2008 verbenone application, a
mortality attributed to MPB in the vicinity of the number of 2007 MPB attacks were found in
recreation area in the mid 1990s. treated forested strips. Many of the attacks
appeared to have occurred after the time of the
In 2008, the sixth and final annual application of 2007 verbenone treatment evaluation in October,
verbenone, the anti-aggregation pheromone for 2007. MPB in north Idaho typically fly in July.
MPB, was made to forested strips between ski
runs at Lookout Pass Ski and Recreation Area to Because of the volume of observed MPB
protect susceptible lodgepole pine trees from mortality in 2008, no verbenone was applied in
MPB attack. From 2003-2006, two applications 2009 to high priority forested strips.
of Pherotech Inc.’s 5-gram verbenone pouch
were made. The first application was made in Long term solutions to the bark beetle mortality
late May, early June and the second application at Lookout Pass Ski and Recreation area will
was made in mid-July. In 2007, Beetle Block require silvicultural prescriptions which address
Verbenone 7-gram pouch produced by Synergy the underlying stand susceptibility to MPB.
Semiochemical Corporation was the only EPA More immediate action may be required to
registered verbenone product available. One address the number of MPB killed lodgepole
pine trees adjacent to ski runs. These dead trees
may pose a risk to skiers in the future.
INTRODUCTION
Lookout Pass Ski and Recreation Area operates lodgepole pine with verbenone, the anti-
under a Forest Service special use authorization aggregation pheromone for MPB. The IPNF
administered by the Idaho Panhandle National also conducted an extensive survey of forested
Forests (IPNF). Located on the border of the Strips on the existing ski hill, and on forested
IPNF and Lolo National Forests, the recreation Strips between new runs that were created in the
area has provided winter recreation opportunities summers of 2003 and 2005. From 2003-2008
for over 70 years. Currently, the forests in and FHP has invested $161,423 in support of
around the recreation area have a significant verbenone treatments at Lookout Pass Ski and
component of lodgepole pine which is being Recreation area.
attacked by mountain pine beetle (Dendroctonus
ponderosae) (MBP). MPB may attack and kill This report summarizes information on the 2003-
many of the larger diameter lodgepole pine trees 2008 verbenone application and a post treatment
in forested buffer strips between designated ski evaluation of 2008 treated units. Verbenone
runs during the course of the current outbreak. treatment ended in 2008.
In order to protect the lodgepole pine in forested
TREATMENT HISTORY
strips between existing ski runs, the IPNF
requested Forest Health Protection (FHP)
Applications of verbenone began on the ski hill
technical and financial assistance. FHP has
in 2003, when 40 acres of susceptible forested
provided technical assistance (Appendix 1) and
strips were treated. The treatment area was
suppression funding (Appendix 2) annually since
expanded in 2004 to cover 100 acres, 120 acres
2003 to treat from 40 (2003) to 130 (2008) acres
in 2005, 126 acres in 2006, and 130 acres in
of forested strips having large-diameter
2007 and 2008 (Table 1, Table 3, Figure 1).
TABLE 1: Verbenone treatment history for forested strips on Lookout Pass Ski and Recreation Area
(Figure 1).
Gig BSEeNAEGg igeP e k|X|Seeeo e e
Eo re 2 KK ie re < 2 nd o
z,ie) Gioe) z e) z oe)
g o < io o
[ Mates| Y et ice
ri ree<
KVo[2ekee))e
Yes Yes Yes es.| Yes 2007 and 2008-Additional 8 acres treated below
Skiway, M, & N
FIGURE 1: Lookout Pass Ski and Recreation Area Ski Hill Schematic. Yellow letters refer to treatment
polygons in forested leave strips between established runs.
Aah gene
re,
i
47°27'01.36°N 115°42'18.44" W
2008 TREATMENT
evaluation. MPB in lodgepole pine typically has
In 2008 we used the 7-gram verbenone pouch
peak flight in July.
produced by Pherotech, Inc. The 7-gram pouch is
designed to last the entire flight period of the
2008 RESULTS
mountain pine beetle. No second application of
verbenone is recommended by the manufacturer
when using the 7-gram pouch. We stapled 20 7- In June 2009, FHP personnel evaluated all 19
verbenone treatment areas and one untreated area
gram verbenone pouches per acre to trees on a 15
at Lookout Pass using the Forest Insect and
meter grid.
Disease Tally System (FINDITS). Between two
As we applied the verbenone in June of 2008, we and 15 variable radius plots using a basal area
factor (BAF) of 10 were randomly placed within
noted many green 2007 MPB attacked trees,
treatment polygons. Diameter at breast height
which would change to red that fall. Many of
these trees had not been detected during the 2007 (DBH), species, and MPB activity (current
attack, last year’s attack, older attacks,
unattacked) were recorded for each tree in the in 2007 and MPB brood were completing
plot. Data was then summarized using the development as verbenone was being applied in
FINDITS program (Bentz 2000). spring 2008). Many researchers feel that if
currently infested trees are present in a treatment
FINDITS survey results for 2008, 2007, and area, the beetle produced aggregation
older mountain pine beetle attacks are pheromones will overpower manmade sources of
summarized in Table 2 for evaluated polygons. anti-aggregation pheromone.
Treatment efficacy in 2008 was highly variable.
In some of the treatment units no 2008 MPB Variable treatment results may also be a result of
losses were recorded (E, F, H, AA, CC, and the change in the formulation of verbenone and
wDiDt)h. 20I0n 8o tMhePrB unimtosr,t arleistuyl tsg rweaetreer mtohrane, mleisxse dt han, aapppplliiccaattiioonns moeft h5o-dgsr.a m Inp opuacshte sy,e arosn ew ei n mlaatdee Matwyo/
or about equal to 2007 levels (Table 2). early June and a second in early to mid-J uly.
It is not possible to determine why results were iWni teha rltyh eJ u7n-eg. raImt ipso puocshseisb lew et haotn ltyh ea pppoluicehde so nce
variable. In many of the units experiencing stopped releasing verbenone before the end of
pMrPioBr tmoo r2t0a0l8i tyt,r eMatPmBen tsi nf(etshtee dt rterees esw ewreer e atptraecskeendt lMaPteB sefalsiognht , atatlalcoksw.i ng MPB to make successful
TABLE 2: FINDITS survey results for verbenone treated polygons on Lookout Pass Ski and Recreation
area, 2008. Grey shaded rows represent unit with 2008 MPB attacks.
Polygon (# Treatment History 2008 2007 Older Total
plots)
MPB MPB MPB Recorded
2008 2007 2006 | 2005 Attacks Attacks Attacks MPB
TPA* TPA*
TPA* TPA*
me © MN 7© 7) Z 30.76 ' 38.5
© eicnh&| e Yes HCas T aa
Z2) 16.54
|<& ne ie iS 0am OPsk a
&
pal ‘ S) f cS) Z, S 2|o2| 6
ig?)7 ) 7<i §@ 7) ;§¢ >) A ;§f = ) weA S ete B S
Kt <K!e ] 4pam6n N4 rw0)J :ioehod O S (oee) a" ee CO 4.83
ig?)7 2) @ DH
i |mone a & Yes
M(10) Yes r|ae es Yes Y Plelol2
es >|i G|o ]C SlIAle
N&O (15) Yes Yes Yes Y —|a
3.47
P(10) Yes Yes Yes Yes IEoSeS U0r 0S} |GuRor !|9 .2I3 A}
AA(3) Yes Yes Yes Yes
BB(4) Yes Yes Yes
Yes 5= mh AN +=" = "\ o me) N wn
Yes Yes Yes Yes
4.74
Yes Yes Yes Yes
Yes Yes Yes Yes Ge&
Below Yes Yes RNeo No -= ; \Si o®) c-bod i2 o) \© tdooeknN| t= o o |i o!b| Co6e .02
nN So ~ nN \©2 74.95
CURRENT STAND CONDITIONS
FINDITS stand information from the 2009 hazard for additional MPB losses. The only way
evaluation is summarized in Table 3. Though to affect the susceptibility of the ski and
land managers have applied verbenone for six recreation area to MPB and reduce the hazard
years, MPB remains active on the ski hill and a rating 1s to address the quantity and quality of
number of the treatment polygons remain at high lodgepole pine available to beetles (Randall &
Tensmeyer 2000, Appendix 3).
TABLE 3: 2009 Lookout Pass Ski and Recreation Area verbenone project polygon stand condition
summary from FINDITS stand information: polygon size (acres), average trees per acre (TPA), average
lodgepole pine (LPP) TPA, stand basal area (BA), lodgepole pine BA, stand quadratic mean diameter
(QMD), lodgepole pine QMD, and Randall Tensmeyer 2000 mountain pine beetle hazard rating.
Polygon | Area Average |L PP TPA | Average |L PP BA Average | LPP | Hazard
(# plots) | (Acres) TPA (%) BA (%) QMD QMD | Rating
nak a
163
@ mo @am [TI[1S057 %
EO) soca [105 [60°S7%)
FO 5 56H 105 35 (19%) |
Hey [os [ise [tao [a [eosom fr4a [at [wate
er [351_ 3 _[s1) [_sz_ [[aaac r) oPr1osm )[12 9| Mo derate
K@__ [ht [2a7_ [parc oo) my[ iss [assc om) [TT PTi ) \oO [Medea
C@_[25_[so_com_ [1i[55s s3 [r7ssc%oom 0[R_o [_RO |H h
M10 7 baiiyos) as [aisq ioom) [83 [83__| Hi
8 6 8 oO
N&O 14.4 231 231 (100% ) 126 126 (100%) | 11.; 0 11.0 | Moderate
r(1a5)y [98 [as [rowiay [ie [eream [oR [98 [Moderate
XAG) 5
BB : eon as [ih
cea [425 a5 e rise1 00%) [3
DDG |
FEO 6 )
FFD 8 Poa
oo
|
10 3 3 320 (96%) 168 (97% 10.1 10.3
RATE OF LOSS PREDICTION
A 10-year rate of loss prediction model mortality using the Cole-McGregor model were
developed by Cole and McGregor (1983) was within 25% of the actual mortality observed.
run on survey information collected in the spring
of 2009 from the forested strip polygons. In most of the forested strips between ski runs on
Results are summarized in Table 4. Cameron et the ski hill, continued MPB activity may result in
al. (1990) found that in areas where MPB more significant losses to the lodgepole pine
populations became established, predictions of component.
TABLE 4: Polygon size, Randall/ Tensmeyer (2000) mountain pine beetle hazard rating, and Cole-
McGregor (1983) mountain pine beetle in lodgepole pine 10-year rate of loss prediction model (if beetle
populations become established in a stand) results for leave strip polygons surveyed in spring 2009 on the
Lookout Pass Ski and Recreation Area.
Estimated 10- | Estimated %
2008 Live LP Yr Post LP Pine
Pine TPA* Outbreak LP TPA* Lost
Pine TPA*
1. ys
On 5
2
LS 0:80 ||M oderate: |i mino aes
1
2.96 — | Moderate
*TPA = Trees per Acre
SUMMARY OF BEETLE RELATED
FINDINGS
The lodgepole pine trees and forests in and Ski and Recreation Area is a significant
around Lookout Pass Ski and Recreation Area component of the recently completed
are currently susceptible to bark beetle attack. Vegetation Management Plan for the ski hill.
Many of the forested strips between ski runs on It will assist managers as they plan the future
Lookout Pass are comprised primarily or of the ski hill.
exclusively of lodgepole pine (Table 3). They
would be substantially altered if beetle Because of ongoing losses in the lodgepole
populations became established and lived up to pine of treated polygons and the high cost of
their potential for tree killing. Continued MPB applications, additional verbenone treatments
losses on the ski hill could be prevented. will not be supported by Forest Health
Silvicultural treatments geared towards removing Protection prevention, suppression, and
trees currently infested by bark beetles and restoration project funds.
reducing stand hazard to bark beetles by
influencing the quantity, density, and/ or size of Managers might want to consider individual
residual lodgepole pine trees are the best options tree protection using insecticidal sprays for
to prevent additional losses at this time. certain high value trees or for all trees in
Preventative insecticide sprays may also be important buffer strips to protect against
useful to protect individual high value lodgepole MPB and IPS attack (verbenone alone is not
pine trees. Planting non-susceptible species effective against IPS). To be effective,
would also reduce stand hazard. insecticidal sprays would need to be applied
with a high pressure device which may be
Aerial detection surveys and FINDITS surveys difficult to maneuver on steep terrain. The
in untreated polygons show MPB continues to cost of individual tree protection may be
kill trees in and around the ski hill. prohibitive over a large scale. Please contact
FHP for current insecticide and application
While the use of verbenone may have reduced recommendations.
MPB caused mortality from 2003-2008, MPB
continued to kill trees in treated polygons. Implementation of the recently completed
Verbenone is not effective in preventing attacks vegetation management plan would be
by other bark beetles such as IPS. IPS, often helpful as the District deals with the
associated with logging activity and wind throw, continued MPB activity in the Ski and
has been active on the ski hill in recent years, Recreation Area. Prevention and restoration
though no current activity was documented strategies should be considered rather than
during evaluations in the spring of 2009. the current emphasis on verbenone based
suppression strategies.
RECOMMENDATIONS
o Recent lodgepole pine mortality on the ski
hill has been substantial. While direct
suppression efforts may increase the
longevity of lodgepole pine remaining in the
short term, it would be prudent to consider
what options are available to compensate for
ongoing losses of this species. An evaluation
of the current conditions and threats to the
vegetative component of the Lookout Pass
LITERATURE CITED
Bentz, Barbara J. 2000. Forest Insect and Disease Tally System (FINDIT) User Manual. USDA Forest
Service Rocky Mountain Research Station General Technical Report RMRS-GTR-49. April 2000. 12 p.
Cameron, D.E., A. R. Stage, N. L. Crookston. 1990. Performance of three mountain pine beetle damage
models compared to actual outbreak histories. USDA Forest Service Intermountain Forest and Range
Experiment Station Research Paper INT-435. 13p.
Cole, W.E. and M.D. McGregor. 1983. Estimating the rate and amount of tree loss from mountain pine
beetle infestations. USDA Forest Service Intermountain Forest and Range Experiment Station Research
Paper INT 318. 22 p.
Gibson, Ken. 2003. Personal Communication. USDA FS Region | Forest Health Protection Entomologist.
Missoula, MT.
Munson, Steve. 2003. Personal Communication. USDA FS Region 4 Forest Health Protection
Entomologist. Ogden, UT.
Progar, Robert. 2003. Personal Communication. USDA FS Region 4 Forest Health Protection
Entomologist. Boise, ID.
Randall, Carol and Greg Tensmeyer. 2000. Hazard rating system for the mountain pine beetle in
lodgepole pine using the Oracle database and the Forest Service IBM platform. USDA-FS-R1-Report 00-
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