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White firWhite fir Recovery and Mortality Recovery and Mortality
following thefollowing theDouglas-fir Tussock MothDouglas-fir Tussock Moth Bear Mountain Outbreak Bear Mountain Outbreak
(2005-2007)(2005-2007)Siskiyou County, CASiskiyou County, CA
2 - 4 years post outbreak2 - 4 years post outbreak
Donald R. Owen
Background information on DFTM, Orgyia psuedotsugata
•White fir is the principal host in CA and SW USDouglas-fir and grand fir are principal hosts elsewhere
•One year life cycle with egg hatch in June and pupation in July•5-6 instars typical•1st 3 instars account for 10% of defoliation•Last instar accounts for > 60% of the defoliation•Outbreaks are cyclic with a 7-10 year return interval
Outbreaks may last 1-4 years•In order to cause significant damage, an outbreak would typically go through 3 phases, each phase corresponding to one DFTM generation (one year)
• Release – rapid population increase; little, if any, noticeable defoliation
• Peak – highest population and most severe defoliation; natural enemies begin to exert control by the end of the generation
• Decline / Collapse – population initially high, but natural enemies cause population collapse; defoliation may be more widespread, but less severe
Damage
•Damage = top kill, mortality, and growth loss•Defoliation is measured as the % of crown completely defoliated•90% of mortality occurs in trees with > 90% defoliation•Trees with < 50% defoliation rarely die•Top-kill follows a similar trend•Defoliation varies significantly across the landscape, with heavy defoliation occurring in hotspots up to 50 acres in size•Hotspots typically occur on ridges, upper slopes, and poorer sites•To prevent damage, control should target the Peak Phase and concentrate on predicted hot spots•Control during the Decline Phase may reduce defoliation that year, but may have negligible effect on top kill and mortality•Overall, stands experience growth loss initially, but long-term effect is usually neutral or positive
Bear Mountain DFTM Outbreak
2005 No early detection monitoring in this area; population release occurs without notice
2006 Peak phase; high egg mass counts in some locations in the fall, but parasites and dead DFTM larvae and pupae are common; egg masses are relatively small and there is a low ratio of egg masses to pupal cases; 2,455 acres of defoliation
2007In hotspots, some trees or tops of trees do not break bud (mortality and top kill); DFTM population is initially high, but shows noticeable decline by 3rd instar in areas with the heaviest defoliation; parasites abundant; no egg masses could be found in the fall (population collapse); 7,444 acres of defoliation. This outbreak followed the typical 3-yr sequence of population release, peak, and decline
Defoliation
as mapped from aerial survey
in 2006
Peak Phase of the
Bear Mountain Outbreak
Outbreak centered on Bear Mountain and north of Sheepheaven Butte
Expansion of the outbreak in 2007
was due to mostly light defoliation in surrounding areas
WF WF RecoveryRecovery – Bear Mtn DFTM – Bear Mtn DFTM OutbreakOutbreak
2007
2009
Light defoliation
Photo pt 10
2011
WF WF Recovery Recovery – Bear Mtn DFTM – Bear Mtn DFTM OutbreakOutbreak
2009
2007
Photo pt 13
5-20 % defoliation 201
1
WF WF Recovery Recovery – Bear Mtn DFTM – Bear Mtn DFTM OutbreakOutbreak
2007
2009
Photo pt 13
5-20 % defoliation
2011
2007
WF WF Recovery Recovery – Bear Mtn DFTM – Bear Mtn DFTM OutbreakOutbreak
200720 % defoliation
Photo pt 12
2009
2011
WF WF RecoveryRecovery – Bear Mtn DFTM – Bear Mtn DFTM OutbreakOutbreak
2007
2009
20 % defoliation
Photo pt 12
2011
WF WF RecoveryRecovery – Bear Mtn DFTM – Bear Mtn DFTM OutbreakOutbreak
2007
2009
Photo pt 20
25-55 % defoliation
2011
WF WF RecoveryRecovery – Bear Mtn DFTM – Bear Mtn DFTM OutbreakOutbreak
2007
2009
Photo pt 20
25 % defoliation
2011
WF WF RecoveryRecovery – Bear Mtn DFTM – Bear Mtn DFTM OutbreakOutbreak
2007
2009
Photo pt 20
55 % defoliation
2011
WF WF RecoveryRecovery – Bear Mtn DFTM – Bear Mtn DFTM OutbreakOutbreak
2007
2009
25 - 30 % defoliation
Photo pt 05
2011
WF WF RecoveryRecovery – Bear Mtn DFTM – Bear Mtn DFTM OutbreakOutbreak
2009
25 - 30 % defoliation
Photo pt 05
2007201
12007
WF WF RecoveryRecovery – Bear Mtn DFTM – Bear Mtn DFTM OutbreakOutbreak
2009
33 % defoliation
Photo pt 07
2007
2011
WF WF RecoveryRecovery – Bear Mtn DFTM – Bear Mtn DFTM OutbreakOutbreak
2007
2009
33 % defoliation
Photo pt 07
2011
WF WF RecoveryRecovery – Bear Mtn DFTM – Bear Mtn DFTM OutbreakOutbreak
2007
2009
40 % defoliation
Photo pt 02
2011
WF WF RecoveryRecovery – Bear Mtn DFTM – Bear Mtn DFTM OutbreakOutbreak
2007
2009
40 % defoliation
Photo pt 02
2011
WF WF RecoveryRecovery – Bear Mtn DFTM – Bear Mtn DFTM OutbreakOutbreak
2007
2009
Photo pt 14
50 % defoliation 201
1
WF WF RecoveryRecovery – Bear Mtn DFTM – Bear Mtn DFTM OutbreakOutbreak
2009
2007
Photo pt 14
50 % defoliation
2011
WF WF RecoveryRecovery – Bear Mtn DFTM – Bear Mtn DFTM OutbreakOutbreak
2007
2009
Photo pt 17
55 % defoliation2011
WF WF Recovery Recovery – Bear Mtn DFTM – Bear Mtn DFTM OutbreakOutbreak
2007
2009
Photo pt 17
55 % defoliation
2011
WF WF RecoveryRecovery – Bear Mtn DFTM – Bear Mtn DFTM OutbreakOutbreak
2009
200760 % defoliation
Photo pt 03
2011
WF WF RecoveryRecovery – Bear Mtn DFTM – Bear Mtn DFTM OutbreakOutbreak
2007
200960 %
defoliation
Photo pt 03
2011
WF WF RecoveryRecovery – Bear Mtn DFTM – Bear Mtn DFTM OutbreakOutbreak
2007
2009
70 - 30 % defoliation
Photo pt 06
2011
WF WF RecoveryRecovery – Bear Mtn DFTM – Bear Mtn DFTM OutbreakOutbreak
70 - 30 % defoliation
2007 200
9
Photo pt 06
2011
WF WF RecoveryRecovery – Bear Mtn DFTM – Bear Mtn DFTM OutbreakOutbreak
2007
2009
60 % defoliation
Photo pt 11
2011
WF WF RecoveryRecovery – Bear Mtn DFTM – Bear Mtn DFTM OutbreakOutbreak
2007
2009
60 % defoliation
Photo pt 11
2011
WF WF RecoveryRecovery – Bear Mtn DFTM – Bear Mtn DFTM OutbreakOutbreak
2007
2009
Photo pt 19
60 % defoliation
2011
WF WF RecoveryRecovery – Bear Mtn DFTM – Bear Mtn DFTM OutbreakOutbreak
2007
2009
Photo pt 19
60 % defoliation
2011
WF WF MortalityMortality – Bear Mtn DFTM – Bear Mtn DFTM OutbreakOutbreak
2007
2009 (dead 2008)85 %
defoliation
Photo pt 04
WF WF Mortality Mortality – Bear Mountain DFTM – Bear Mountain DFTM OutbreakOutbreak
2007
2009 (dead 2008)
90 % defoliation
Photo pt 01
WF WF MortalityMortality– Bear Mtn DFTM – Bear Mtn DFTM OutbreakOutbreak
2007
2009(dead 2008)
Photo pt 16
95 % defoliation
WF WF MortalityMortality– Bear Mtn DFTM – Bear Mtn DFTM OutbreakOutbreak
2009 (dead 2008)
2007
Photo pt 18
95 % defoliation
2011
WF WF MortalityMortality– Bear Mtn DFTM – Bear Mtn DFTM OutbreakOutbreak
2007
2009 (white fir dead
2008)
WF 90-100 % defoliation
Ponderosa pine
Photo pt 08
2007
2009
Photo pt 08
2011
Ponderosa Pine Ponderosa Pine RecoveryRecovery – Bear Mtn – Bear Mtn DFTM OutbreakDFTM Outbreak
Douglas-fir Douglas-fir RecoveryRecovery – Bear Mtn – Bear Mtn DFTM OutbreakDFTM Outbreak
2007
2009
Photo pt 15
1-30 % defoliation
2011
DF DF RecoveryRecovery – Bear Mtn DFTM – Bear Mtn DFTM OutbreakOutbreak
2007 200
9
Douglas-fir
Photo pt 15
1-30 % defoliation
2011
2007
References Beckwith, RC. 1978. In: The Douglas-fir Tussock Moth: A Synthesis. MH Brookes, RW Stark, and RW Campbell, eds. USDA For. Serv. Tech. Bull. No. 1585. p 66. Mason, RR and RF Luck. 1978. In: The Douglas-fir Tussock Moth: A Synthesis. MH Brookes, RW Stark, and RW Campbell, eds. USDA For. Serv. Tech. Bull. No. 1585. p 40 & 44. Mason, RR and JW Baxter. 1970. Food preference in a natural population of the Douglas-fir tussock moth. J. Econ. Entomol. 63(4):1257-9. Shepard, RF, DD Bennett, JW Dale, S Tunnock, RE Dolph, and RW Their. 1988. Evidence of synchronized cycles in outbreak patterns of Douglas-fir tussock moth, Orgyia psuedotsugata (McDunnough)(Lepidoptera:Lymantriidae). Mem. Ent. Soc. Can. 146:107-21 Torgersen, TR and DL Dahlsten. 1978. In: The Douglas-fir Tussock Moth: A Synthesis. MH Brookes, RW Stark, and RW Campbell, eds. USDA For. Serv. Tech. Bull. No. 1585. p 47-53. Wickman, BE. 1963. Mortality and growth reduction of white fir following defoliation by the Douglas-fir tussock moth. USDA For. Serv. Res. Pap. PSW-7. 14p. Wickman, BE. 1978. A case study of a Douglas-fir tussock moth outbreak and stand conditions 10 years later. USDA For. Serv. Res. Pap. PNW-244. 22p.
References continued
Wickman, BE. 1979. Douglas-fir tussock moth handbook. How to estimate defoliation and predict tree damage. Ag. Hdbk No. 550. 15p. Wickman, BE. 1980. Increased growth of white fir after a Douglas-fir tussock moth outbreak. J. For. 78:31-33. Wickman, BE. 1986. Growth of white fir after Douglas-fir tussock moth outbreaks: long-term records in the Sierra Nevada. USDA For. Sev. Res. Note PNW-440. 8p. Wickman, BE. 1988. Tree growth in thinned and unthinned white fir stands 20 years after a Douglas-fir tussock moth outbreak. USDA For. Sev. Res. Note PNW-RN-477. 11p. Wickman, BE.1990. Mammoth Lakes revisited – 50 years after a Douglas-fir tussock moth outbreak. USDA For. Sev. Res. Note PNW-RN-498. 6p. Wickman, BE, RR Mason, and CG Thompson. 1973. Major outbreaks of Douglas-fir tussock moth in Oregon and California. USDA For. Serv. Gen. Tech. Rep. PNW-5. 18p.
Williams, CB Jr, JM Wenz, DL Dahlsten, and NX Norick. 1979. Relation of forest site and stand characteristics to Douglas-fir tussock moth (Lep. Lymantriidae) outbreaks in California. Bull. Soc. Entom. Suisse. 52:297-307.