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Initial and Future Stand Development
following Mountain Pine Beetle in
Harvested and Uncut
Lodgepole Pine Stands
Byron Collins
Colorado State University
Forest, Rangeland & Watershed Stewardship
Mountain Pine Beetle Outbreak
Mountain Pine Beetle in North America
~450,000 Hectares in Colorado
~12 million ha in British Columbia
- British Columbia: Sparse regeneration in uncut stands
Raffa, K.F., Aukema, B.H., Bentz, B.J., Carroll, A.L., Hicke, J.A., Turner, M.G. and Romme, W.H. 2008. Cross-scale drivers of natural disturbances prone to anthropogenic amplification: the dynamics of bark beetle eruptions. BioScience 58:501-517. doi:10.1641/B580607.
Management Response
Sulphur Ranger District – Arapaho-Roosevelt NF
• 3,700 ha since 2000
• 2.5x increase over ’90 -’99
• 40% potentially treatable (slope, access)
1910-1919
1920-1929
1930-1939
1940-1949
1950-1959
1960-1969
1970-1979
1980-1989
1990-1999
2000-2009
Tre
ate
d A
rea
(h
a)
0
1000
2000
3000
4000 S ing le T ree/G roup Selection
Shelterwood/Seed Tree C ut
C learcut
Objectives
• Characterize cut & uncut stands- quantify advance regeneration and recruitment
• Pre-outbreak vs. outbreak- green vs. red
• Growth- advance regeneration and recruitment
• Future forests
- project stand growth, species composition
Research Approach
• Historic Data – Green vs. Red
- Seedling and stand survey data, Sulphur RD-
Arapaho-Roosevelt NF
• Current
- Operational scale study of management vs. no-
action
Management Research Areas
North Platte Basin
- Colorado State Forest
- Routt National Forest – Parks RD
Upper Colorado Basin- Arapaho-Roosevelt NF -Sulphur
RD/ Fraser Experimental Forest
- Routt NF – Yampa RD
Fraser Experimental Forest
• 10 harvest units paired with 10 adjacent uncut stands
• Range of overstory removal (partial cut, clear cut)
• Range of slash management (lop and scatter, whole tree harvest)
Harvest: Fall & Winter 2007-2008
Methods
• Seedling plots (1/100 acre, 114 plots)
• Overstory transects (5 x 150 m, 69 transects)
• Growth measurements (250 trees)
Harvest 2007 - 2008
• 39% - 86% basal area removed
Stand Pairs
1 2 3 4 5 6 7 8 9 10
Ba
sa
l A
rea
m2 h
a-1
0
10
20
30
40
50
Untreated
Harvested
Forest Composition – Uncut Stands
• Lodgepole makes up
majority of basal area
- 45% - 100% of total BA
- 74% mortality (60% - 93%)
P ine F ir
Spruce
AspenP in
e F ir
Spruce
Aspen
Ba
sa
l A
re
a m
2 h
a-1
0
20
30
D ead Lodgepole
O verstory
5
U nderstory
4
3
2
1
Recruitment
Pine Fir Spruce Aspen
Ste
ms
ha
-1
0
1000
2000
3000
4000
Untreated
Harvested
• 3x more recruitment in harvested stands (aspen and lodgepole)
• Continued fir and pine recruitment in uncut stands beneathdeteriorating canopy
Effects of Canopy Condition at HarvestGreen vs. Red
• Post-harvest seedling recruitment is similar during outbreak as prior to outbreak
Pre-outbreak O utbreak
Re
cru
itm
en
t (t
ree
s h
a-1
)
0
5000
10000
15000
Frequency of Density:Seedling Recruitment
Among all species:
• In uncut stands seedlings were found in 90% of plots (18% > 3000 trees ha-1)
• In harvested stands seedlings were found in 80% of plots (56% > 3000 trees ha-1)
U ntreated
Fre
qu
en
cy
(%
of
plo
ts)
0
20
40
60
80
100
Fre
qu
en
cy
(%
of
plo
ts)
0
20
40
60
80
100
H arvested
0 370 1000 3000 10000 500001
0 370 1000 3000 10000 500001
Advance Regeneration
Pine Fir Spruce Aspen
Ste
ms
ha
-1
0
1000
2000
3000Untreated
Harvested
• Density did not differ between harvested and uncut areas
• ~4000 stems/ha-1
all species in cut and uncut stands
• Subalpine fir half of all advance regeneration
• Species composition differs from overstory
Frequency of Density:Advance Regeneration
Among all species:
• In uncut stands adv. regeneration was found in 97% of plots (49% > 3000 trees ha-1)
• In harvested stands adv. regeneration was found in 92% of plots (39% > 3000 trees ha-1)
U ntreated
Fre
qu
en
cy
(%
of
plo
ts)
0
20
40
60
80
100
Fre
qu
en
cy
(%
of
plo
ts)
0
20
40
60
80
100
H arvested
0 370 1000 3000 10000 500001
0 370 1000 3000 10000 500001
Growth Response to HarvestRecruitment
• Lodgepole grew 30% more in cut stands compared to uncut
He
igh
t G
row
th (
cm
)
0
1
2
3
U ntreated H arvested
Growth Response to Reduced CanopyAdvance Regeneration
Lodgepole Pine:
- Responding to reduced canopy cover
- Increased leader growth in 2009 in untreated and harvested stands (23%)
Subalpine Fir:
- Less leader growth in harvested stands
- 2x more leader growth (2008 and 2009) in untreated stands
- 23% of trees in harvested stands had no new leader growth in 2009
Lodgepole P ine
Le
ad
er
Gro
wth
(c
m)
0
2
4
6
Subalpine F ir
U ntreated
Le
ad
er
Gro
wth
(c
m)
0
2
4
6
2008
2009
H arvested
U ntreated H arvested
Stand Growth Projections
Partia l C ut
0 50 100 150 200
0
10
20
30
40
50
C learcut
0 50 100 150 200
Ba
sa
l A
rea
(m
2 h
a-1
)
0
10
20
30
40
50
U ncut
0 50 100 150 200
0
10
20
30
40
50Lodgepole
F ir
Spruce
Aspen
Tota l B
as
al
Are
a (
m2 h
a-1
)B
as
al
Are
a (
m2 h
a-1
)
Used initial findings and FIA data to predict changes in basal area and species composition over time
• Uncut Stands: Subalpine fir, lodgepole pine evenly mixed (50 to 100 yrs)
• Partial Cut: Aspen and subalpine fir dominant for 50 years then aspen becomes less important
• Clear cut: lodgepole pine is dominant
* Forest Vegetation Simulator, Forest Inventory and Analysis Data
Summary of Results
Seedling recruitment occurred in 90% of uncut and 80% of harvested stands
Advance regeneration was found in > 90% of uncut and harvested stands
Species composition of seedling recruitment and advance regeneration differed between cut and uncut stands
Lodgepole increased height growth in cut and uncut stands
Subalpine fir grew poorly in cut stands
Summary of Results (cont.)
Cut and uncut stands will recover pre-outbreak basal area in 80 – 100 years
Future species composition dependent on treatment
Special ThanksGraduate Committee
Chuck Rhoades - Rocky Mountain Research Station
Bill Romme - Forest Range & Watershed Stewardship
Rob Hubbard - Rocky Mountain Research Station
Patrick Martin - Horticulture & Landscape Architecture
Funding Support
• Tony Cheng - Colorado Forest Restoration Institute
• Clint Kyhl - USFS Region 2, Bark Beetle Initiative
Technical Assistance
Mike Battaglia, Lance Asherin, Laurie Porth, David Turner
Field AssistanceAnna Johnson, Landon Gryzkowski, Tyson Wormus, Chad Kooistra, Jarrett
Tishmack, Bryn Evans, Adam Heath, Brett Macalady, Amanda Morrison, Phil
Bissell
Questions?