spread of beech bark disease in the eastern united states and its relationship to regional forest...
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Spread of Beech Bark Disease in the Eastern United States and its Relationship to Regional Forest Composition
Randall Morin, Sandy Liebhold, Patrick Tobin, Kurt Gottschalk, and Gino Luzader
USDA Forest Service
World Conference on Natural Resource ModelingJune 14-7, 2005 Humboldt State University
Uses of American Beech
• Valuable for wildlife
• Only nut producing tree species in the northern hardwood forest type
• Beech wood has many uses
Sites of Nectria infection become walled off with callus tissue, which gives the tree a pockmarked appearance
and an exotic or native canker fungus
Nectria coccinea var. faginataor the native Nectria galligena
Beech Bark DiseaseBeech bark disease is an insect-fungus complex
involving the beech scale insect
Cryptococcus fagisuga
Research Questions
• Is the spread of BBD characterized by continuous radial expansion or by a more complex pattern of discontinuous spread?
• Is the rate of spread affected by beech density?
• What is the effect of BBD on regional forest species composition?
Historical Spread
Historical Spread
Current (2003)27% of habitat
57% of host
0
500
1000
1500
2000
2500
1920 1940 1960 1980 2000 2020
Year
Dis
tan
ce (
km
)
ContinuousDisjunct
0
200
400
600
800
1000
1200
1400
1600
1920 1940 1960 1980 2000 2020
Year
Dis
tan
ce (
km
)
Continuous
y = 13.99x - 26694
R2 = 0.9415
0
300
600
900
1200
1500
1930 1940 1950 1960 1970 1980 1990 2000
Year
Dis
tan
ce
(k
m)
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
1920 1940 1960 1980 2000 2020 2040
Year of BBD Infestation
Am
eric
an b
eech
BA
0
50
100
150
200
250
1953 1968 1980 1993
Gro
win
g s
tock v
olu
me/a
cre
(cu
. ft
.)
American beechSugar mapleEastern hemlock
New York
0
50
100
150
200
250
300
350
400
450
500
1948 1966 1973 1983 1997
Gro
win
g s
tock
vo
lum
e (c
u.
ft.)
American beechSugar mapleEastern hemlock
Vermont
Conclusions
• BBD is characterized by continuous radial expansion and a more complex pattern of discontinuous spread
• Rate of spread does not seem to be affected by beech density
• BBD may result in increases in associated species
QUESTIONS?
CONTACT INFORMATIONRandall Morin
11 Campus Blvd., Suite 200Newtown Square, PA 19073