MOFEP Studies Armillaria Root DiseaseRelated Forest Structure and Decline Dynamics

1
MOFEP StudiesArmillaria Root Disease-RelatedFor
est Structure and Decline Dynamics

• Johann N. Bruhn and Jeanne D. Mihail
• Department of Plant Microbiology Pathology,
• University of Missouri - Columbia

2
Other Team Members

• Deana Baucom, UMC, Plant Microbiol. Pathology
• Travis Clark, U. of Toronto, Botany
• Walter Gassmann, UMC, Plant Microbiol.
  Pathology
• Thomas C. Harrington, Iowa St. Univ, Plant
  Pathology
• Daniel C. Dey, USDA Forest Service, Columbia, MO
• Randy G. Jensen, MDC, Ellington, MO
• John M. Kabrick, USDA Forest Service, Columbia,
  MO
• Kathryn Kromroy, USDA Forest Service, St. Paul,
  MN
• James B. Pickens, Mich. Tech. Univ., School of
  Forestry
• Susan J. Taylor, UMC, Plant Microbiol.
  Pathology
• James J. Wetteroff, Jr., UMC, Plant Microbiol.
  Pathology

3
MOFEP-based Presentations

• Peer-reviewed Publications
• 2 USFS MOFEP GTRs
• 1 Springer-Verlag book chapter
• 1 Forest Pathology
• 2 Mycological Research (2 in revision)
• 1 Mycopathologia
• Non-Peer-reviewed Publications
• 4 IUFRO Congress Proceedings chapters (3 in
  press)
• Invited Symposium Presentations
• Ecological Society of America, 2003
• American Phytopathological Society, 2002
• Oral Presentations and Posters
• APS, ESA, IMC6, IMC7, IUFRO, MSA, NCFPW, NAMS,
  MOMS, SESA, UMC LSW,
• Other Presentations and Workshops
• MO SAF, No Central Forest Pest Workshop

4
(No Transcript)
5
Ozark Armillaria Species

• Armillaria mellea Everywhere Pathogenic
• Armillaria tabescens Ridges Pathogenic
• Armillaria gallica Breaks, Protected
  Necrotrophic
• Armillaria fast mellea Since harvest ????

6
Alu1 RFLPs
A. gallica
A. mellea
A. tabescens
A. fast mellea
7
A. mellea
Mycelial Fan
Rhizomorphs
8
A. tabescens
9
A. gallica
10
Forest Decline

• Predisposing Factors ?
• Inciting Factors
• Contributing Factors ?
• (opportunistic)

11
Disturbance Factors

• Armillaria root disease
• Climatic stress
• Fire
• Insect outbreaks
• Silviculture

12
Past Confusion
on a grape root
on an oak stump root crossing the buttress root
of a healthy ash tree
13
Genet Mapping
Compatible
Incompatible
A. gallica
A. ostoyae
14
A Few Expanding Genets?or Death by a Thousand
Cuts?

• Important to know
• for modeling purposes
• for framing management

15
Logging Damage
16
Does the Story Ever End ??
Ancient Root channels

• soaking wet white rot
• zone lines
• (pseudosclerotial plates)

17
The Role of Stumps
Re-assess models of Dey et al. 1996 and Dey and
Jensen 2002
What is a tree???? How old is this tree???? How
old is this Armillaria????
18
Relationship between sprout abundance and
presence of Armillaria on stump buttress roots.
19
Relationship between stump diameter, stump
sprouting, and presence of Armillaria
20
Armillaria influences

• overstory species composition succession
• soft mass production
• bird nesting habitat
• lizard snake abundance
• fuel buildup
• decline episode frequency severity
• silvicultural planning

21
Summary

• slow sculptors, forest engineers
• disturbance agents which also respond to
  disturbance
• Long-lived genets are both predisposing factors
  and opportunistic pathogens.
• Sprout age and stump age are not necessarily
  related to root system age and root disease
  severity.
• Live and dead Quercus stumps carry significant
  Armillaria infections.
• In rocky Ozark soils, Armillaria-decayed root
  channels are avenues for root development and
  infection.

22
Objectives Timetable

• 2005/2006
• complete stump evaluations in field
• develop logging damage training materials
• publish molecular studies
• (??Establish a TSI study outside MOFEP??)
• 2006/2007
• 10-yr re-evaluation of wound closure
• pilot logging damage training session(s)
• complete lab identifications of stump isolates
• (??Continue TSI study??)
• 2007/2008
• comparison of oak decline across harvest
  treatments
• analysis publication of wound closure data
• publish stump sprout studies
• (??Conclude initial TSI study??)