Modeling bark beetle effects in a fireshed assessment An application of the Westwide Pine Beetle Model & the FFE in the Deschutes National Forest Andrew McMahan 1 Alan Ager 2, Helen Maffei 3, Eric L Smith 4 1 Systems Analyst, ITX, Inc., Ft. Collins 2 Operations Research Analyst, PNW Research Station 3 Forest Pathologist, Deschutes National Forest, Bend 4 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-b  NoTRT+B  TRT-b  TRT+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 ( )

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

Average stand Basal Area (sq ft / acre) Green= No Beetles Red= with beetles Dashed= treated

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

Basal area beetle-killed (BAK) No Treatment (NoTRT) scenario Mixed Conifer (MC) and “other” PAGs

Basal area beetle-killed (BAK) Thinned (TRT) scenario Mixed Conifer (MC) and “other” PAGs

Basal area beetle-killed (BAK) Mixed Conifer (MC) PAG Both TRT & NoTRT scenarios

Basal area beetle-killed (BAK) “Other” PAGs Both TRT & NoTRT scenarios

Orange: experience greater simulated beetle mortality after TRT Greens & blue: “protected”

Potential Volume Mortality (Severe Fire) (Millions of Cu Ft)

Acres Active Crown Fire Potential

Polygons with Active Crown Fire Potential in 2020 Landscapes Without Treatments Without Beetles (ORANGE) on top of With Beetles (RED) Red: stands classed as “Active” Crown Fire if beetle outbreak

Polygons with Active Crown Fire Potential in 2020 Landscapes With Treatments Without Beetles (ORANGE) on top of With Beetles (RED) Red: stands classed as “Active” Crown Fire if beetle outbreak

Surface Fuels 2020 Thinned landscape No Beetles

Surface Fuels 2020 Thinned landscape With Beetles

Orange  Blue: Increase in surface fuels due to beetles Treated Landscape 2018

Orange  Blue: Increase in surface fuels due to beetles Untreated Landscape 2018

Orange  Blue: Decrease in standing fuels due to beetles Untreated Landscape 2018

Orange  Blue: Decrease in standing fuels due to beetles Treated Landscape 2018

Treatment Effect Beetle Effects

Growth EffectsBeetle 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 mortality after TRT Greens & 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

Acknowledgements Western Wildland Threat Assessment Center Prineville Jim Stone Dana Simon Lance David, ITX, Inc (FHTET) Gary Dixon, FMSC Frank Krist, FHTET Vern Thomas, ITX, Inc. (FHTET)

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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 criteria Case 2: For those that are NOT classed as mixed conifer, they must either: a) have > 100 tpa LPP > 9"dbh, OR b) have > 50% host AND >50% of the host must be PP