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)