Drought and Bark Beetles: Status Report and Plan for Research · Drought and Bark Beetles: Status...
Transcript of Drought and Bark Beetles: Status Report and Plan for Research · Drought and Bark Beetles: Status...
Drought and Bark Beetles: Status Report and Plan for Research
By
Michael R. Wagner [1], Monica Gaylord [1], Thomas E. Kolb [1], and Joel D. McMillin [2]
[1] Northern Arizona University School of Forestry, Flagstaff, AZ [2] US Forest Service, Forest Health Protection, Flagstaff, AZ
Outline
• Current Drought • Bark Beetles (BB) • Drought/BB Impacts • Drought or BB? • Current Research • Future Research Needs
-3
-2
-1
0
1
2
3
BC
Bel
ow-a
vera
ge
Abo
ve-a
vera
ge
prec
ipita
tion
pre
cipi
tatio
n
AD
500 1000 1500 2000
Y ear
(Grissno-Mayer et al. 1997; Wagner et al. 2000)
0
Annual Precipitation in Flagstaff, AZ (1976-2003)
0 5
10 15 20 25 30 35 40
)
76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 00 01 02 03
Year
Ann
ual p
reci
pita
tion
(inch
es 50 yr (1951-2000) AVE ANN PRECIP = 21.7 inches
Pine Bark Beetles in Arizona
Most important
• Pine engraver beetles (Ips) -11 species in AZ
• Western pine beetle • Roundheaded pine beetle • Mountain pine beetle • Southern and Mexican pine
beetle (Chiricahua Mts.) • Larger Mexican pine beetle • Red turpentine beetle
Least important
0 5
10 15 20 25 30 35
li i i l i
Pi
Ponderosa mber pinyon Apache Ch huahua Br st econe Mex can pinyon
Host tree
No.
of b
ark
beet
le
spec
ies ne feeding Scolytidae in AZ
Juniper feeding Scolytidae in AZ5
4
3
2
1
0
Alligator Utah Rocky One-Mount. seeded
Hos tree
No.
of b
ark
beet
le s
peci
es
Ponderosa Pine Bark BeetlesAvailable life history
information Genus No. of species, % Yes No Partial Ips 12 41.4% 3 6 3 Dendroctonus 6 20.7% 6 0 0 Pityophthorus 4 13.8% 0 4 0 Pityogenes 2 6.9% 0 1 1 Carphoborus 1 3.4% 0 1 0 Hylastes 1 3.4% 0 0 1 Hylurgops 1 3.4% 1 0 0 Pityoborus 1 3.4% 0 1 0 Pityokteines 1 3.4% 0 1 0
9 29* 100.0% 10 14 5 (* potentially 5 additional species to be verified)
Feeding Guild for Ponderosa Pine Bark Beetles
Small Trunks and Genus Species Twigs branches Large branches Roots Ips Dendroctonus Pityophthorus Pityogenes Carphoborus Hylastes Hylurgops Pityoborus Pityokteines
9
12 6 4 2 1 1 1 1 1
29*
0 0 4 0 x 0 0 x 0 6
0 0 0 0 x 0 0 x 0 2
12 6 0 2 0 1 1 0 1
23
0 0 0 0 0 x x 0 0 2
X: feeding on both tissue types; * Potentially 5 additional species to be verified
Ponderosa pine mortality caused by Dendroctonus and Ips spp. complex
in AZ and NM, 1995-2003
0 1995 1997 1998 1999 2000 2001 2002 2003
AZ NM
50,000 100,000 150,000 200,000 250,000 300,000 350,000 400,000 450,000 500,000
Acr
es
1996
Year
(Sources: Forest Insect and Disease Conditions in the SW Region, 1995-2003)
Ponderosa pine mortality caused by Ips beetles in AZ and NM, 1995-2003
0 1995 1996 1997 1998 1999 2000 2001 2002 2003
AZ NM
50,000 100,000 150,000 200,000 250,000 300,000 350,000 400,000 450,000 500,000
Acr
es
Year
(Sources: Forest Insect and Disease Conditions in the SW Region, 1995-2003)
Ponderosa pine mortality caused by Western pine beetles in AZ and NM, 1995-2003
0 1995 1996 1998 2001 2002 2003
AZ NM
10,000
20,000
30,000
40,000
50,000
60,000 A
cres
1997 1999 2000
Year
(Sources: Forest Insect and Disease Conditions in the SW Region, 1995-2003)
Ponderosa pine mortality caused by Mountain pine beetles in AZ and NM, 1995-2003
0 1995 1996 1997 1998 1999 2000 2001 2002 2003
AZ NM
2,000
4,000
6,000
8,000
10,000
12,000 A
cres
Year
(Sources: Forest Insect and Disease Conditions in the SW Region, 1995-2003)
Ponderosa pine mortality caused by Roundheaded pine beetles in AZ and NM, 1995-2003
0 1995 1996 1997 1998 1999 2000 2001 2002 2003
AZ NM
5,000
10,000
15,000
20,000
25,000
30,000 A
cres
Year
(Sources: Forest Insect and Disease Conditions in the SW Region, 1995-2003)
The meaning of acres of bark beetle mortality
• Area of bark beetle activity • Intensity of mortality varies with activity polygon• Qualitative decision made during aerial survey • Same acre can have mortality over several years• Number of dead trees estimated
Pinon and ponderosa pine mortality detected from aerial survey in Arizona, 2001-2003
2001 2002 2003
Prec
ipita
tion
(inch
es)
Pinyon-Juniper, Spruce-firOak woodland,And/Or Chaparral
40
35
30
25
20
15 Ponderosa pine
10Grass Land
5
4,000 5,000 6,000 7,000 8,000 9,000 10,000 11,000
Elevation (feet)
Drought or Bark Beetles?
• Correlation of bark beetles and drought • Anecdotal reports of death w/o bark beetles
• Little evidence from skilled necropsy • Rigorous experimental test is lacking • Drought as inciting agent • Conceptual understanding of inciting factors versus
sustaining factors • Does it matter?
Relationship between bark beetle infested acres and winter precipitation (January to April)
R2 P
0 0 150 250
)
2000 1994 2001
2003
2002 y = -3588.8x + 703791
= 0.826, = 0.033
100,000 200,000
300,000
400,000
500,000 600,000
700,000
50 100 200
Winter precipitation (mm
Infe
sted
acr
es in
AZ
stat
ewid
e
(Bark beetle species included the complex of Dendroctonus brevicomis, D. ponderosae, D. adjunctus, and Ips spp. on ponderosa pine)
Y X
Z
N1
N2
Critic
al T
hres
hold
Beetle #’s
Epidemic Domain
Endemic Domain
R2 R1
Host Resistance
Does It Matter?
• Drought can cause direct mortality • Bark beetles can cause direct mortality • Bark beetles require suitable host • Outbreaks can persist after drought ends
• Active management (thinning) can reduce the risk of both drought and bark beetle mortality
Southwest (AZ/NM) Ponderosa Pine Bark Beetle Research
• ≈ 40 Studies (manuscript) • 80% in Progress • 80% Flagstaff Based (NAU, RMRS, FHP)• ≈ 95% Federal Funds
Ponderosa Pine Bark Beetle Research Topics
• Stand structure, density, restoration effects • Tree physiology, resistance • Life history, seasonal and elevational patterns
• Ecological effects (mistletoe, birds, CWD) • Prevention and tree protection
Important Research Questions
• Can stand/landscape scale treatments mitigate bark beetle outbreak?
• Are current fuel risk reduction treatments well suited for reducing bark beetle risk?
• What will be the combined effect of thinning from below and bark beetles on future forest?
Important Research Questions (Continued)
• Which aspects of bark beetle communitystructure, life history strategy, and naturalenemies are most important to populationdynamics?
• Long-term economic, social, and ecologicaleffects of widespread loss of Arizona forests?
• Are current monitoring tools (pheromone,aerial detection) adequate?
Summary
9 Unprecedented tree mortality in SW 9 Probably drought induced 9 Likely related to overstocked forest condition 9 Outbreak will continue for several years 9 Paucity of basic understanding of all aspects of
bark beetles 9 Coordinated SW research program needed
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