SIMULATION AND PLOT REMEASUREMENT ANALYSIS
10 YEAR CHANGES IN STAND STRUCTURE AND DENSITY
VS PREDICTIONS OF THE WESTERN ROOT DISEASE
MODEL
HELEN MAFFEIGREG FILIP
LANCE DAVID KRISTEN FIELDS
OBJECTIVES
• ASSESS THE CAPABILITY OF THE WESTERN ROOT DISEASE MODEL TO PREDICT CHANGES IN STRUCTURE , DENSITY AND FUEL LOADS CAUSED BY ARMILLARIA ROOT DISEASE BY COMPARING THESE PROJECTIONS TO ACTUAL MEASURED CHANGES IN THE FIELD
40 YEAR PROJECTIONARMILLARIA ROOT DISEASE
BASE MODEL ONLY USING WRDM
WESTERN ROOT DISEASE (WRDM) OVERVIEW
DIAGRAM OF ROOT DISEASE CENTER
STAND
RR CENTER
INFECTED ROOTS
Western Root Disease Impact Model (WRDIM) Overview
• Infects new host trees through root contact with the root system of an infected tree. • (The probability of contact is based on assumptions re the shape and
geometry of roots and root growth).
Western Root Disease Impact Model (WRDIM) Overview
• Kills tree when a threshold amount of root the root system is colonized by root disease .
• Bark beetles can also kill root disease infected trees.
Western Root Disease Impact Model (WRDIM)
• Root disease inoculum dies out when root decays. Other factors being equal the larger the root the longer it persists
OPUS ADMINISTRATIVE STUDY
STUDY DESIGN R6 FHP AND PNW
PLOT ESTABLISHENT FUNDED BY WINEAMA NF
REMEASUREMENTS FUNDED BY PTIPS – STDP
DESIGNED, MEASURED AND MAINTAINED BY R6 FHP AND WINEMA NF
Established by:
Helen Maffei and Gregorio Armillarius
Leo Torba and Phil Jahns in 1991
Study Area Characteristics
• 166 acres• White fir/Shasta red fir• Occasional ponderosa pine and DF in the
overstory• Little evidence of harvest• Armillaria root disease very active• Elevation approx 5,000 feet• East Aspect• 13 stands—full range of ARD severity • 147 plots—full range of ARD severity
Significant (p=000) negative
linear relationship between RR
Severity Rating and plot density
(N=145)
ROOT ROT RATING VS TOTAL CC 1991
ADJ. R2 = 0.28
0
10
20
30
40
50
60
70
80
90
100
0 2 4 6 8 10
root rot rating
tota
l %
cc
Methods: RR severity rating and plot density
Root disease causes an
overall decrease in density as
represented by % canopy
cover
Methods: The effect of Armillaria Root Disease on Density
STAND 818 HEAVILY INFESTED
1 2 3 4 5 6 7 8 9 10 11
PLOT NUMBER
% C
AN
OP
Y C
OV
ER
STAND 816 LIGHTLY INFESTED
0
10
20
30
40
50
60
70
80
90
100
1 2 3 4 5 6 7 8 9 10 11 12
PLOT NUMBER
% C
AN
OP
Y C
OV
ER
Red =1991
Blue=2002
Study Area Characteristics
• Late Successional Reserve
Cascad
e Can
al
Opus Study Area, No Treatment
FR 3633
FR 200
Study Location
SCALE OF COMPARSONS
• INDIVIDUAL PLOT LEVEL (147)
Started with plots because:
-IMAP calibration uses inventory plots, not SE. plot data & pest models are currently being used to calibrate VDDT state transition models for IMAP project for the effects of I & Disease
-Scale more consistent with IMAP-- 1/6 acre (30 m pixel) -Short time frame---Expect to see more decadal change
• STAND LEVEL (13)
WHAT CONSITUTES SUCCESS?
11 YR PREDICTIONS:
• ARE BETTER CORRELATED WITH WHAT REALLY HAPPENED USING THE WRDM THAN THE BASE MODEL ALONE
¤ THE TRAJECTORY OF THE CHANGE IS SIMILAR TO WHAT WE KNOW ACTUALLY HAPPENS
WHAT CONSITUTES SUCCESS continued
ANY NEEDED CALIBRATION MUST BE:
• LOGICAL STRAIGHTFORWARD THAT:
¤ CAN BE APPLIED ACROSS ALL STANDS WITH CONSISTENT RESULTS
¤ CAN BE MEASURED AND REPEATED IN OTHER SITUATIONS (NOT JUST TINKERING AROUND
WITH MODIFIERS UNTIL IT COMES OUT RIGHT)
WHAT CONSITUTES SUCCESS?
PREDICTIONS WITH BASE MODEL + WESTERN ROOT DISEASE MODEL SHOULD HAVE:
• BETTER CORRELATIONS WITH THE OBSERVED THAN WITH THE BASE MODEL ALONE
• AVERAGE PREDICTIONS OF INDICATOR VARIABLES THAT ARE:
– Not significantly different from average observed value – Significantly different from projections with base model alone
INDICATOR VARIABLES
DENSITY
• CHANGES IN % CANOPY COVER
STRUCTURE
• CHANGES IN % CANOPY COVER FOR 4 SIZE CLASSES
Structure.. % Canopy Cover of 4 size class groups:
Size class 1. DBH 0 to 5 inches (SEEDLINGS AND SAPLINGS
Size class 2. DBH 5+ to 9 inches (POLES)
Size class 3. DBH 9+ to 21 inches (MEDIUM)
Size class 4. DBH 21+ inches (LARGE TREES)
% CC Calculated using FVS cover model
SORNEC Variant
Methods
Plots/size classes subdivided into 2 root disease severity groups
1. No apparent root disease 2. Mod-Heavy root disease
BASE MODEL CALIBRATION
• SDI MAX SET TO 600 FOR WHITE FIR AND SHASTA RED FIR
• OTHER SPECIES USE DEFAULT VALUES
WRDM CALIBRATION
• RECODED SH TO WF--DOES NOT SEEM TO RECOGNIZE SHASTA RED FIR IN BARK BEETLE COMMAND
FIR ENGRAVER BEETLE ATTACK IS VERY IMPORTANT COMPONENT OF DEATH FROM ROOT DISEASE.
• ROOT ROT AREA IS SET TO 1 ACRE FOR INDIVIDUAL PLOTS
• 100% OF THE AREA IS IN ROOT DISEASE FOR PLOTS WITH INITIAL ROOT DISEASE SEVERITY RATINGS OF 2 OR GREATER.
RESULTS
DBH 9-21 rr=0
R2 = 0.32
-25-20-15-10
-505
1015
-40 -30 -20 -10 0 10
measured delta cc
pred
icte
d de
lta c
c
Results:
Predicted vs actual 11 year change in cc for 9-21 dbh trees in plots no initial root disease on plot..n=118
dbh 9-11 base model only
R2 = 0.37
-20
-15
-10
-5
0
5
10
15
-40 -30 -20 -10 0 10
measured delta cc
pre
dic
ted
de
lta
cc
DBH 9-11 BASE MODEL
RR NOT ON PLOT
RR ON PLOT
SIZE
CLASS
CORRELATION WITH ACTUAL CHANGE IN CC (ADJ R2)
SO SO+ARD SO SO+ARD
ALL .01 .08 .06 .16
SS .08 .09 .05 .01
Pole .00 .01 .17 .35
MEDIUM .37 .32 .03 .07
LARGE .31 .33 .23 .16
STAND COMPARISIONS
SIZE
CLASS
CORRELATION WITH ACTUAL CHANGE IN CC (ADJ R2)
RR IN PLOT
ACTUAL SO SO+ARD -0.0
ALL -8.3 1.8 -11.0
SS * * *
Pole * * *
MEDIUM -9.7 -2.7 -12.0
LARGE 2.3 1.8 -0.0
SIZE CLASS SO SO+ARD
ALL .16 .06
SS .01 .12
Pole .14 .07
MEDIUM .02 .09
LARGE .17 .23
CORRELATION WITH ACTUAL CHANGE IN CC (ADJ R2)
SAMPLE DESIGN ISSUES RELATED TO INVENTORY
PLOTS
Thoughts
• For our landscape the model reflects the general trend in changes in structure and density caused by root disease
• However changes occurring within size classes do not appear to be well correlated; although some are better than others
• Calibration and trouble shooting of WRDM is difficult because its difficult to isolate and correct individual causes
• We need to keep working on this
Methods
Key variables and groupings used to evaluate the performance of FVS and the WRDM in predicting 11 year change in vertical fuel loads
Change in vertical dead fuels (tons/acre)
Methods—Predicted vs Measured Fuel Loads by Root Disease Severity
Root Disease Intensity/Severity:
• Root Disease Severity Rating (Hagle); • Recorded by plot; 1991
Fuel loads:•Predicted and Measured
Standing Dead (tons/acre)•Down Dead (not completed)•Calculated by FVS Fire Effects
Model
Predicted vs. Measured Standing Dead (tons/acre)
R2 = 0.3677
0
20
40
60
80
100
0 50 100 150 200
Measured Standing Dead
Pre
dic
ted
Sta
nd
ing
D
ea
d
Predicted vs Measured Standing Dead (tons/acre) in non infected
plots (n=31)
Adj R2 = 0.42
020406080
100
0 50 100 150 200
Measured standing dead
Pre
dic
ted
sta
nd
ing
dead
Predicted vs Measured Standing Dead (tons/acre) in lightly
infected plots (n=70)
Adj R2 = 0.38
020406080
100
0 50 100 150 200
Measured standing dead
Pre
dic
ted
sta
nd
ing
dead
Predicted vs Measured Standing Dead (tons/acre) in mod-heavily
infected plots (n=44)
Adj R2 = 0.19
0
20
4060
80
100
0 50 100 150 200
Measured standing dead
Pre
dic
ted
sta
nd
ing
dead
How good are the root disease model predictions
Barriers to assessment
•Complex structure and calibration needs
•Great calibration of base model required prior to assessment or impossible to discern
Tentative conclusions re 11 year WRDM projections of density and structural change in unmanaged
plots
•*Under predicts changes in dead vertical fuels
ADJ. R2
1990
RR RATING =0
1990
RR RATING >1
WRDM
SIG (P>.98)
A SO ARM SO WRDM SO WRDM
TOTAL CC
LARGE TREES
EMERGENT
POLES
SS
Methods—Armillaria Root Disease and Fuel Loads
Root Disease Intensity/Severity:
• Root Disease Severity Rating (Hagle);
• Recorded by plot; 1991
Fuel loads:• Standing Dead• Calculated by FVS Fire Effects
Model
MethodsEvaluation variables denoting changes in density,
structure and fuel load over 11 years.
Change in % CCChange in % CC by size class Change in vertical dead fuels
(tons/acre)