Modeling bark beetle effects in a fireshed assessment

An application of the Westwide Pine Beetle Model & the FFE in the

Deschutes National Forest

Andrew McMahan1

Alan Ager2, Helen Maffei3, Eric L Smith4

1 Systems Analyst, ITX, Inc., Ft. Collins2 Operations Research Analyst, PNW Research Station3 Forest Pathologist, Deschutes National Forest, Bend4 Program Manager, Quantitative Analysis, FHTET, Ft Collins

Primary Objective

• Simulate effects of bark beetles on stands in context of landscape-scale fuel mgmt and wildlife habitat mgmt projects– How might beetle dynamics respond to fuel

treatments?– How might beetle dynamics affect fuel

dynamics (spatially and temporally)?

Secondary Objectives

• Simulate beetle “sanitation” concurrent with simulated thinning treatments

• Consider dwarf mistletoe effects on beetle dynamics (partially done)

• Consider fire effects on bark beetle dynamics (not done)– simulate effects of live, fire-scorched trees on

stand attractiveness to beetles

Scenario design• With & without thinning treatment• With & without beetles

NoTRT-bNoTRT+BTRT-bTRT+B

• Treatments include WWPBM “sanitation”– Sanitation removes dead, beetle-infested trees

and their beetles• Treatments are SDI-based thins from

below (thinning by point)

Simulation Details

• SDIMAX for pines set to 429 (Cochran)• If BSDI > 236 (55% of 429),

and year=2003, then...• SetPThin to target SDI=150 (from below)• Favor retention of pines and DF

• Run PPE for 7 3-yr cycles (2000-2021)

WWPB Model details

• Beetles (BKP) initialized into stands containing “significant” amounts of host in an amount = 1% of host BA

• “Severe” bark beetle outbreak initiated in simulation year=2005 for 5 years

Oregon

Deschutes National Forest

Five Buttes Analysis Area

Davis Fire (2003)

Mixed Conifer PAGs

0

20

40

60

80

100

120

140

160

2000 2005 2010 2015 2020

NoTRT-b All NoTRT+B All

TRT-b All TRT+B All

Average stand Basal Area (sq ft / acre)Green=No Beetles

Red=with beetles

Dashed=treated

0

2

4

6

82000 2005 2010 2015 2020

BA

K/a

cre

TRT other

TRT MC

NOTRT other

NOTRT MC

Basal area beetle-killed (BAK; sq ft / acre) in Mixed Conifer (MC) PAG and “Other” PAGs

0

2

4

6

82000 2005 2010 2015 2020

BA

K/a

cre

NOTRT other NOTRT MC

Basal area beetle-killed (BAK) No Treatment (NoTRT) scenario

Mixed Conifer (MC) and “other” PAGs

0

2

4

6

82000 2005 2010 2015 2020

BA

K/a

cre

TRT other TRT MC

Basal area beetle-killed (BAK) Thinned (TRT) scenario

Mixed Conifer (MC) and “other” PAGs

0

2

4

6

82000 2005 2010 2015 2020

BA

K/a

cre

TRT MC NOTRT MC

Basal area beetle-killed (BAK) Mixed Conifer (MC) PAG

Both TRT & NoTRT scenarios

0

2

4

6

82000 2005 2010 2015 2020

BA

K/a

cre

TRT other NOTRT other

Basal area beetle-killed (BAK) “Other” PAGs

Both TRT & NoTRT scenarios

Orange: experience greater simulated beetle mortalityafter TRTGreens & blue: “protected”

0

100

200

300

400

500

600

2000 2005 2010 2015 2020

NoTrt+B NoTrt-b

TRT+B TRT-b

Potential Volume Mortality (Severe Fire)

(Millions of Cu Ft)

0

10

20

30

40

50

2000 2005 2010 2015 2020

Thou

sand

s of

Acr

es

NoTrt-b NoTrt+B

Trt-b Trt+B

Acres Active Crown Fire Potential

Polygons with Active Crown Fire Potential in 2020Landscapes Without Treatments Without Beetles (ORANGE) on top ofWith Beetles (RED)

Red: stands classed as“Active” Crown Fireif beetle outbreak

Polygons with Active Crown Fire Potential in 2020Landscapes With Treatments Without Beetles (ORANGE) on top ofWith Beetles (RED)

Red: stands classed as“Active” Crown Fireif beetle outbreak

Surface Fuels2020Thinned landscapeNo Beetles

Surface Fuels2020Thinned landscapeWith Beetles

Orange Blue:Increase in surface fuelsdue to beetles

Treated Landscape 2018

Orange Blue:Increase in surface fuelsdue to beetles

Untreated Landscape 2018

Orange Blue:Decrease in standing fuelsdue to beetles

Untreated Landscape 2018

Orange Blue:Decrease in standing fuelsdue to beetles

Treated Landscape 2018

Mixed Conifer Forest types

0

10000

20000

30000

40000

50000

60000N

OTR

T-b

NO

TRT+

BTR

T-b

TRT+

B

NO

TRT-

bN

OTR

T+B

TRT-

bTR

T+B

NO

TRT-

bN

OTR

T+B

TRT-

bTR

T+B

NO

TRT-

bN

OTR

T+B

TRT-

bTR

T+B

NO

TRT-

bN

OTR

T+B

TRT-

bTR

T+B

NO

TRT-

bN

OTR

T+B

TRT-

bTR

T+B

NO

TRT-

bN

OTR

T+B

TRT-

bTR

T+B

Acr

es

OM

OS

YM

UR

SE

SI

Treatment Effect Beetle Effects

"Other" forest types

0

10000

20000

30000

40000

50000

60000

70000

80000

90000

NO

TRT-

bN

OTR

T+B

TRT-

bTR

T+B

NO

TRT-

bN

OTR

T+B

TRT-

bTR

T+B

NO

TRT-

bN

OTR

T+B

TRT-

bTR

T+B

NO

TRT-

bN

OTR

T+B

TRT-

bTR

T+B

NO

TRT-

bN

OTR

T+B

TRT-

bTR

T+B

NO

TRT-

bN

OTR

T+B

TRT-

bTR

T+B

NO

TRT-

bN

OTR

T+B

TRT-

bTR

T+B

acre

s

OM

OS

YM

UR

SE

SI

Growth Effects Beetle Effects

Discussion: BKP migration

• Simulated beetles efficiently find remaining host

• How realistically does the WWPBM simulate beetle migration?– Should in-flight beetle mortality algorithms be

adjusted to account for distance traveled?

Orange: experience greater simulated beetle mortalityafter TRTGreens & blue: “protected”

Discussion: SDIMAX

• Although FVS users may explicitly enter site-specific SDIMAX values, they can be overwritten by FVS when input treelists “disagree”

• Should FVS handle SDIMAX readjustments differently? How?

Summary• WWPB Model can be used in landscape

analyses to simulate effects of beetles on landscape fuel dynamics

• WWPB Model is sensitive to changes in host availability

• ArcFuels—w/ FVS-DB—streamlines landscape-scale FVS simulation-building

• ArcFuels—w/ FVS-DB—simplifies mapping FVS output data

AcknowledgementsWestern Wildland Threat Assessment Center

Prineville

Jim StoneDana Simon

Lance David, ITX, Inc (FHTET)Gary Dixon, FMSC

Frank Krist, FHTETVern Thomas, ITX, Inc. (FHTET)

END

0

5

10

15

20

25

2005 2007 2009 2011 2013 2015

BK

PNOTRT

TRT(wSAN)

SAN_Only(NoTRT)

TRT (withoutSAN)

In all cases BAHost must be > 50 AND BA total > 100 sq ft

Case 1: all stands that are MIXED CONIFER ("MC"), and meet above criteriaCase 2: For those that are NOT classed as mixed conifer,they must either:a) have > 100 tpa LPP > 9"dbh, ORb) have > 50% host AND >50% of the host must be PP