The Effects of Hazardous Fuel The Effects of Hazardous Fuel Reduction Treatments in WUI on the Reduction Treatments in WUI on the Amount of Bark BeetleAmount of Bark Beetle--Caused Tree Caused Tree

MortalityMortality

C. J. FETTIGC. J. FETTIG11, J. MCMILLIN, J. MCMILLIN22, J. A. ANHOLD, J. A. ANHOLD22, R. R. , R. R. BORYSBORYS11 AND S. J. SEYBOLDAND S. J. SEYBOLD11

1 1 PACIFIC SOUTHWEST RESEARCH STATIONPACIFIC SOUTHWEST RESEARCH STATION2 2 FOREST HEALTH PROTECTION FOREST HEALTH PROTECTION –– R3R3

California Forest Pest CouncilCalifornia Forest Pest CouncilWoodland, California 2004Woodland, California 2004

AT RISKAT RISK

>200 million acres to catastrophic wildfire >200 million acres to catastrophic wildfire and/or largeand/or large--scale insect and disease outbreaksscale insect and disease outbreaks

Wildland Fires of 2002:

• 6.7 million acres burned; nearly double 10-year average• 21 firefighters died• numerous homes lost • suppression cost = $1.7 billion• Arizona, Colorado and New Mexico recorded their

largest fires in the last century

Southern California Southern California -- 20032003

745,000+ acres, 20 people, 3400+ homes 745,000+ acres, 20 people, 3400+ homes

2004: Year2004: Year--toto--date (10/22/2004)date (10/22/2004)7,912, 571 acres burned7,912, 571 acres burned1,084 structures consumed1,084 structures consumed>$500 million in suppression costs>$500 million in suppression costs

19951995--2004: 102004: 10--year averageyear average3,672,865 acres burned3,672,865 acres burned

causing:causing:-- deterioration indeterioration inecosystem integrityecosystem integrity

-- increased probabilityincreased probabilityof severe wildfireof severe wildfire

Compared to preCompared to pre--settlement forests,settlement forests,today's shorttoday's short--interval, interval,

firefire--adapted adapted forest ecosystems are:forest ecosystems are:

- denserdenser-- more small treesmore small trees-- fewer large treesfewer large trees-- higher fuel loadshigher fuel loads

18991899

19931993

Alpine County, CAAlpine County, CA

Gruell, G. E. 2001. Fire in the Sierra Gruell, G. E. 2001. Fire in the Sierra Nevada forests: a photographic Nevada forests: a photographic interpretation of ecological change interpretation of ecological change since 1849.since 1849.

HFRA (H.R. 1904)• hazardous fuel reduction on 20 million acres

• >50% must be in the WUI

December 3, 2003December 3, 2003

Wildfire Risk Evaluation Maps Wildfire Risk Evaluation Maps –– WUIWUIColorado Springs, Colorado (Colorado Springs, Colorado (FirewiseFirewise))

WUI ConcernsWUI Concerns

•• Aesthetics, air quality, structure protection, Aesthetics, air quality, structure protection, and risk are paramountand risk are paramount

•• Likely, increased reliance on mechanical Likely, increased reliance on mechanical treatments for precision and risk reductiontreatments for precision and risk reduction

•• For mechanical, costs are >3X than in For mechanical, costs are >3X than in nonnon--WUIWUI

Berry, A. H. and H. Hesseln. 2004. The effect of the WUI on presBerry, A. H. and H. Hesseln. 2004. The effect of the WUI on prescribed burning cribed burning costs in the Pacific Northwestern United States. J. For. 102: 3costs in the Pacific Northwestern United States. J. For. 102: 333--37.37.

• To determine the most effective method of minimizing impacts caused by Ips and other bark beetle species during hazardous fuel reduction treatments

IpsIps--nn--Chips: Effective Slash Chips: Effective Slash Management for Hazardous Fuel Management for Hazardous Fuel Reduction Treatments in the WUI Reduction Treatments in the WUI

or a Recipe for Disaster?or a Recipe for Disaster?

Lop and Scatter

Pile and Burn

Whole Tree Removal

Conventional Wisdom

Chipping reduces amount of bark beetle-caused tree mortality as chips are not viable host material.

Six et al. 2002. Pine engraver colonization of logging residuesSix et al. 2002. Pine engraver colonization of logging residues created using created using alternative slash management systems in western Montana. W. J. Aalternative slash management systems in western Montana. W. J. Appl. For 17: 96ppl. For 17: 96--100.100.

CHIPS

2003 Study 2003 Study –– RCBDRCBD• Treatments:

1. chips, randomly dispersed

2. chips, raked

3. lop & scatter

4. untreated control

• Seasonal effect – spring vs. fall

Partially funded by a Special Technology Development Program graPartially funded by a Special Technology Development Program grantnt

1432 120.27° W

0

100

200

May Jun Jul Aug Sep Oct Nov0

3

Date

SPRING FALL

Ips paraconfusus

Ips pini

Fettig et al. 2004. Spatial and temporal distributions of four bark beetle species (Coleoptera: Scolytidae) along two elevational transects in the Sierra Nevada. Pan. Pacific Entomol. In review.

Kaibab NF, Arizona

Apache-Sitgreaves NF, Arizona

Tahoe NF, California

3 BLOCKS3 BLOCKS

Lop and ScatterLop and Scatter

Chips Chips –– Random DistributionRandom Distribution

Chips Chips –– 2 m Rake2 m Rake

Untreated ControlUntreated Control

Tahoe NF (BLOCK 1)Tahoe NF (BLOCK 1)

Thinning prescription:

1. Thin all conifers < 30 cm (11.9”) dbh

2. Buck slash to 1.2 m in lop & scatter plots

3. Slash depth < 46 cm

0.4 ha plots0.4 ha plots

prepre--treatmenttreatment postpost--treatmenttreatment

Tahoe NF SiteTahoe NF Site

prepre--treatmenttreatment postpost--treatmenttreatment

0

50

100

150

200

250

300

350

400

Pre-treatment Post-treatment

Tree

s/ac

re ControlSU/CHIPSU/RAKESU/LOP

0

50

100

150

200

250

Pre-treatment Post-treatment

Basa

l are

a (f

t2 /ac)

ControlSU/CHIPSU/RAKESU/LOP

Ips attacks – 1 week post Ips galleries – 2 wks post

RTB attacksRTB attacks

Western pine beetleWestern pine beetleIps paraconfususIps paraconfusus

Mountain pine beetleMountain pine beetle

Results Results –– % of trees % of trees attacked by bark beetlesattacked by bark beetles

• Significant treatment effect observed (F3,8 = 5.5, P = 0.02)

• No significant seasonal effect observed (F1,6 = 3.3, P = 0.12)

Mean Percentage of Trees Attacked Mean Percentage of Trees Attacked ±± SEMSEM

SpringSpring 17.5 17.5 ±± 4.4 a4.4 a

FallFall 10.110.1 ±± 2.8 a2.8 a

No significant difference between treatment means (P = 0.12)No significant difference between treatment means (P = 0.12)

42% reduction42% reduction

CHIPS CNR LNS CONTROL0

5

10

15

20

25

30Aa

ab

b b

Percentage of trees attacked by bark beetles. Data based on Tahoe NF block through 10/2004.

31% reduction

Results Results –– % tree mortality*% tree mortality*

•• No significant treatment effect No significant treatment effect observed (Fobserved (F3,83,8 = 0.3, P = 0.82)= 0.3, P = 0.82)

•• No significant seasonal effect No significant seasonal effect observed (Fobserved (F1,61,6 = 0.01, P = 0.98)= 0.01, P = 0.98)

* Based on presence of crown fading at time of survey.* Based on presence of crown fading at time of survey.

Mean Percentage of Trees Killed Mean Percentage of Trees Killed ±±SEMSEM

SpringSpring 3.0 3.0 ±± 0.6 a0.6 a

FallFall 3.33.3 ±± 0.9 a0.9 a

No significant difference between treatment means (P = 0.98)No significant difference between treatment means (P = 0.98)

CHIPS CNR LNS CONTROL0

1

2

3

4

5% of trees killed. Stats based on preliminary analysis of partial data set, Tahoe NF block, 10/2004.

Terpene Volatiles Sampling

• Paired T-test

• 10 PIPO harvested from adjacent plantation

• Aeration sampling (24h sample):

Day 1-10: daily

Day 11-20: 13, 16, 18, 21

Day 21-41: 26, 31, 36, 41

275 gallon tanks, 4L/min for 24h, 275 gallon tanks, 4L/min for 24h, PorpakPorpak--QQ((~ 9X/24h)~ 9X/24h)

Terpene elution decay rate

0100200300400500600700800900

1 2 3 4 5 6 7

Days since cutting

Mea

n ar

ea r

atio

Slash a-pineneSlash B-pineneSlash 3-careneSlash MyrceneChips a-pineneChips B-pineneChips 3-careneChips Myrcene

ConclusionsConclusions

•• Large initial difference in the amount of terpenes Large initial difference in the amount of terpenes emanating from chips vs. slashemanating from chips vs. slash

•• Several bark beetle species are attracted to Several bark beetle species are attracted to recently chipped sitesrecently chipped sites

•• BB attacks: chipped > chipped/raked > lopBB attacks: chipped > chipped/raked > lop--nn--scatter or untreated controlscatter or untreated control

•• Raking may be effective for reducing attacksRaking may be effective for reducing attacks

•• Chipping may result in increased levels of tree Chipping may result in increased levels of tree mortalitymortality

Final results will be submitted to WJAF in spring 2005.Final results will be submitted to WJAF in spring 2005.

Acknowledgments Acknowledgments -- PSWPSW

•• LabLab: Dabney, Hamud, McKelvey, Patterson: Dabney, Hamud, McKelvey, Patterson

•• R5R5: Foresthill RD (J. : Foresthill RD (J. SerraSerra, K. Jones), K. Jones)

•• Volcano Creek Enterprises Inc.Volcano Creek Enterprises Inc.

•• Extramural fundingExtramural funding: STDP grant to PSW/R3: STDP grant to PSW/R3