forest ecological relationships: teakettle and plumas lassen administrative study malcolm north,...
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Forest Ecological Relationships: Teakettle and Plumas Lassen Administrative Study
Malcolm North, Sierra Nevada Research Center, Davis, CA [email protected]
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