forest ecological relationships: teakettle and plumas lassen administrative study malcolm north,...

Forest Ecological Relationships: Teakettle and Plumas Lassen Administrative Study

Malcolm North, Sierra Nevada Research Center, Davis, CA mpnorth@ucdavis.edu

What does the information gathered over the last 10 years of Sierran ecological studies suggest for managing forests?

Processed-centered restoration

Historic diameter distribution

Historic spatial patterns

What is the seral development (shrub response, future tree composition) of treated stands?

• What influences the ‘health’ of current and treated forests?

• In fire suppressed mixed conifer, limited water is a primary driver of many ecological processes

• Treatments that reduce stand density, significantly increase water availability, BUT increases in slash and litter can stall process recover

• Fire jumpstarts most processes, boosts environmental and habitat heterogeneity, and significantly increases biodiversity

What is process-centered restoration?(courtesy of Don Falk, Tree Ring Lab, UA)

• Ecological processes are placed at the center of restoration design

• A range of process values estimated (based on suitable reference)

• Composition and structure are varied as needed to bring process within targeted range, or left to equilibrate on their own

Falk 2006; Cortina et al. 2006

Proceed Centered Restoration: Methods

1. Begin with bracketed estimates of (a) fire regime and (b) individual fire events under historical conditions

2. Model effects of structural treatments on fire behavior and effects across a range of prescriptions

3. Set structural prescription to achieve process target values

4. Test model on the ground and adapt

Covington et al. 2001; Fulé et al. 2004; Falk 2006(courtesy of Don Falk, Tree Ring Lab, UA)

Model assumptions and conditions (90th – 95th percentile wx)

• Modeling in FVS 6.31, Nexus 2.0, Behave+• 32-48 km hr-1 windspeed @ 6 m• Slope 5%• Surface fuel moisture:

– 1 hr fuels 3-8%– 10 hr 4-10%– 100 hr 5-12%

• Live fuel moisture 80-100%• Fuel models 9-10

Fulé et al. 2004; Falk 2006

(courtesy of Don Falk, Tree Ring Lab, UA)

• Primarily surface fire, occasional torching OK• Overall flame height 2 m• Headfire spread rate 3 - 4 m min-1

• Fireline intensity 1000 km m-1

• TI 40 km hr-1, CI 65 km hr-1

• Percent mortality by size class– 2% overstory trees ( 40 cm dbh)– 80% saplings and understory trees ( 15 cm dbh)

Agee 1993, Sackett and Haase 1996, Pyne, Andrews et al. 1996

Target (reference) values for key fire behavior and effects (response) variables

Structural (input) variables

Thin progressively across a range of maximum thin diameters: unthinned – 40 cm (16 in). This alters:– Tree density (stems ha-1)– BA (m2 ha-1)– Crown base height distribution (m)– Crown bulk density (kg m-3)– Size distribution (dbh, cm)

Graham et al. 2004; Peterson et al. 2005

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

0.0 5.0 10.0 15.0 20.0 25.0 30.0 35.0 40.0Max thin dbh (cm)

Pro

po

rtio

n o

f m

ax

re

sp

on

se

FVS flame length severe (ft) TI severe (mph) CI severe (mph)

CBD (kg/m 3̂) Stand mortality severe (% BA) Trees/ha

BA (m 2̂/ha) QMD (cm)

Proportion of response by max diameter thinned

#/stems by dbh and species on 20 ac

0

200

400

600

800

10001 5 9 13

17

21

25

29

33

37

41

DBH in 2" classes

# o

f ste

m pilapijecadeabmaabco

Current diameter distribution in fire-suppressed mixed conifer

1760 1770 1780 1790 1800 1810 1820 1830 1840 1850 1860 1870 1880 1890 1900 1910

est.date

0

6

12

27

# e

stab

lishe

d

-6

-3

0

3

6 PD

SI

abcoabmacadepijepilaPDSI

Fire

Before 1865, tree death and recruitment is pulsed by fire and El Nino events

Diameter distribution

0 25 50 75 100 125 150

25 cm dbh size classes

0

10

20

30

85

125

165

205

245

De

nsi

ty (

# o

f st

em

s/h

a)

PretreatmentBurn/no thinUnburned/understory thinBurn/Understory thinUnburned/Overstory thinBurn/overstory thin1865 Reconstruction

Diameter distribution at Teakettle after treatments compared to 1865

Treatment: Tons of C/ha

B.A.I. (cm2/yr)

1865 Reconstruction 150.7 NACurrent condition (Control)

73.3 15.26

Burn only 68.4 16.14Understory thin (CASPO) 61.8 18.68Understory thin and burn 57.1 22.93Overstory thin (shelterwood)

45.4 20.58

Overstory thin and burn 41.4 23.17

Carbon Storage and Rate of Accretion

-90 -50 -10 30 70

x

-100

-50

0

50

yabcoabmacadepijepila

Pretreatment Forest

Highly Clustered

-90 -50 -10 30 70

Xfin

-90

-50

-10

30

70

Yfin

abcocadepijepilaunk

1865 Reconstruction

Slightly clustered

Random

Overstory Thin (similar to DFPZ)

-100 -50 0 50

x

-100

-50

0

50

y

abcocadepijepila

Regular

Clumped

123.4b120.3b92.4b32.3a37.8a39.0aUnk.Snag (stems/ha)

2.5%a1.4%a1.3%a2.1%a2.6%a1.9%aUnk.Other*

8.8%b5.1%b9.2%b12.1%b9.8%b7.9%b26.8%aPinus lambertiana

7.6%b7.4%b3.6%b8.1%b3.9%b6.2%b22.1%aPinus Jeffreyi

22.4%b20.8%b15.8%a9.5%a11.8%a13.4%a14.5%aCalocedrusdecurrens

1.0%a1.2%a2.5%a1.9%a4.7%a3.0%a2.9%aA. magnifica

57.7%b64.1%b67.6%b66.3%b67.2%b67.6%b33.7%aAbies concolor

141.8c372a423.0a200.5b397.7a434.6a393.2aVolume (m3/ha)

24.2b28.9b22.0b21.9b23.4b19.6b49.5aQuadratic mean dbh(cm)

60.2c70.9b80.5a63.4c72.8b80.7aUnkCanopy cover (%)

198.937.0

162.821.3

00

192.333.9

170.820.2

00

NANA

Cut (stems/ha)B.A. removed (m2/ha)

93.6a143.4d353.8e150.3d239.5c469b67aTotal Density (stems/ha)

17.2c37.5b53.7a22.7c41.2b56.4a51.5aBasal area (m2/ha)

Burn/Over-

story thin

Burn/Under-story

thin

Burn only

Overstory thin only

Understory thin

only

Pretreatment

1865Stand attribute

123.4b120.3b92.4b32.3a37.8a39.0aUnk.Snag (stems/ha)

2.5%a1.4%a1.3%a2.1%a2.6%a1.9%aUnk.Other*

8.8%b5.1%b9.2%b12.1%b9.8%b7.9%b26.8%aPinus lambertiana

7.6%b7.4%b3.6%b8.1%b3.9%b6.2%b22.1%aPinus Jeffreyi

22.4%b20.8%b15.8%a9.5%a11.8%a13.4%a14.5%aCalocedrusdecurrens

1.0%a1.2%a2.5%a1.9%a4.7%a3.0%a2.9%aA. magnifica

57.7%b64.1%b67.6%b66.3%b67.2%b67.6%b33.7%aAbies concolor

141.8c372a423.0a200.5b397.7a434.6a393.2aVolume (m3/ha)

24.2b28.9b22.0b21.9b23.4b19.6b49.5aQuadratic mean dbh(cm)

60.2c70.9b80.5a63.4c72.8b80.7aUnkCanopy cover (%)

198.937.0

162.821.3

00

192.333.9

170.820.2

00

NANA

Cut (stems/ha)B.A. removed (m2/ha)

93.6a143.4d353.8e150.3d239.5c469b67aTotal Density (stems/ha)

17.2c37.5b53.7a22.7c41.2b56.4a51.5aBasal area (m2/ha)

Burn/Over-

story thin

Burn/Under-story

thin

Burn only

Overstory thin only

Understory thin

only

Pretreatment

1865Stand attribute

White fir and incense cedar produce far more seed than pines

NB-NT: No burn/no thin

NB-UT: No burn/understory thin

NB-OT: No burn/overstory thin

B-NT: Burn/no thin

B-UT: Burn/understory thin

B-OT: Burn/overstory thin

Canopy Openness Effects on Understory Vegetation CoverP

erce

nt C

over

Herb

Canopy Cover80 40

Canopy Openness

Stanislaus Tuolomne Experimental Forest Methods

of Cutting Plot 1929 Historic forests probably had higher shrub cover

Some studies suggest shrubs are important habitat for birds and small mammals

For Jeffrey or ponderosa pine, if sapling is established, shrub may not reduce survival

However sugar pine may need forest canopy for early growth

How much shrub cover and how distributed?

Summary I: Some suggestions from recent ecological research

Put fire back into the system whenever possible.

Where fire can’t be used, thin stand to control intensity of inevitable wildfire

Trees should not be evenly spaced after thinning

Different treatments by species—not uniform diameter limits

Need to mix it up at multiple scales—leave some dense clumps, some gaps

Plant pine seedlings to overcome natural seeding, shrub competition, and limited mineral soil and direct sunlight

We still don’t know exactly how stands are going to develop in DFPZs, SPLATs or other fuels’ treatments

Summary II: Some suggestions from recent ecological research