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N. Stephenson 10/2015 from Beetle Rock
Drought Mortality: Implications for carbon and fuelsJohn Battles, ProfessorUC Berkeley
DX site: Sequoia Kings Canyon National ParksUSGS Collaborators: Nate Stephenson and Adrian Das
Dead tree cycle CO2
growth
death
CO2
Dead treeLive tree
CO2
1000+ hour fuel
Fate of standing dead trees 1. Decay2. Degrade3. Fall
Species (and size) differences in fall rates
Wood Decay Rates
Dead tree cycle CO2
growth
death
CO2
Dead treeLive tree
CO2
1000+ hour fuel
Time (years)
pre 2017
2027
2037
2047
2057
2067
Biom
ass
(tons
/acr
e)
121
200
350
500
650
800
915
Standing dead tree1000 hr fuel
Live tree
2014-16 mortality event
Dead Tree Cycle: Preliminary modelSequoia Kings Canyon National Parks
2014-2017 mortality event
31% loss of live tree biomass
330% increase in dead tree biomass
2014-2017 Mortality
Fuel Distribution2017 vs 2030By 2030
1000+ hour fuel load doubles
75% of the plots > 100 tons/ac
90% have a least 60 tons/ac
All plots with some 1000+ fuel
Quantifying theoretical risk
The scale of present tree mortality is so large that greater potential for “mass fires” exists in the coming decades…
Stephens et al. 2018Bioscience
Stephens et al. 2018
FOREST RECOVERY AFTER DROUGHT MORTALITY: PRELIMINARY RESULTS FROM SUMMER 2017
Lauren Cox, PhD student, UC Berkeley
Seedlingsstems < 4.5 ft
0
2000
4000
6000
8000
10000
12000
14000
16000
18000
PLUM BRTN CGH YOMI YOPI SIERRA SEKI MTH
Seed
lings
per
acr
e
*
* Data shared by Sharon Hood
0
100
200
300
400
500
600
700
800
900
PLUM BRTN CGH YOMI YOPI SIERRA SEKI MTH
Sapl
ings
per
acr
e
Saplingsstems ≥ 4.5 ft ht, < 4 in DBH
*
* Data shared by Sharon Hood
Shrub Cover
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
PLUM BRTN CGH YOMI YOPI SEKI MTH
Shru
b co
ver
Yosemite Mixed Conifer Site
0
20000
40000
60000
80000
100000
120000
0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%
Stem
s pe
r ac
re
Percent shrub cover
Sequoia-Kings CanyonTrees: stems ≥ 4 in DBH
0
10
20
30
40
50
60
70
80
White fir Incense-cedar Sugar pine Ponderosa pine CA black oak
Basa
l are
a (f
t2ac
-1)
LiveDecay 1
Sequoia-Kings CanyonSaplings: stems ≥ 4.5 ft ht, < 4 in DBH
0
20
40
60
80
100
120
140
160
White fir Incense-cedar Sugar pine Ponderosa pine CA black oak
Sapl
ings
per
acr
e
Sequoia-Kings CanyonSeedlings: stems ≤ 4.5 ft ht
0
100
200
300
400
500
600
700
800
900
1000
White fir Incense-cedar Sugar pine Ponderosa pine CA black oak
Seed
lings
per
acr
e
Yosemite DX SitesSeedlings: stems < 4.5 ft ht
0
2000
4000
6000
8000
10000
12000
14000
White fir Incense-cedar Sugar pine Ponderosa pine Douglas-fir CA black oak
Seed
lings
per
acr
e
YOPIYOMI
Yosemite DX SitesSaplings: stems ≥ 4.5 ft ht, < 4 in DBH
0
5
10
15
20
25
30
35
White fir Incense-cedar Sugar pine Ponderosa pine Douglas-fir CA black oak
Sapl
ings
per
acr
e
YOPIYOMI
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