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?