3rd of 3 Part Training Series

Christopher Woodall

IMPROVING DWM P2+ DATA QUALITY

OUTLINE

QA/QC AnalysisWhat Customers WantMeasurement Errors

Hot and Cold ChecksTop Six List of ErrorsTraining

WHAT CUSTOMERS WANT

A uniform DWM sample design

applied across the entire United

States producing per acre estimates

of fuels, carbon, and wildlife

habitat

N

445

225

90

270

135

360

180

3

2

1

315

MEASUREMENT ERRORS

Establishing TransectsFWD CountsSlope versus Horizontal

DistancesCWD Transect DiameterCWD Decay Class and

SpeciesCorrect Units for Duff and

LitterSample Status for DWM

components

Hot checks

MEASUREMENT ERRORS

Number 1 priority is matching data and determining adherence to MQO’s

Number 2 priority is determining cause for errors…then correcting cause

Cold/Blind Checks

MEASUREMENT ERROR PROPAGATION

CWDDuff/Litter

FWD

Slash

Shrub/Herb

Transect

Database Processin

g Algorithm

s

Core TableMeasurement errors have varying

magnitudes of effect

MEASUREMENT ERROR SIMULATION

0

1

2

3

4

5

6

7

8

5 10 15

Varia

tion

in T

otal

Ton

nage

Est

imat

es (%

)

Simulated Variation (%)

Effect of 5, 10, 15% variation in down woody material measurement variables on total per acre tonnage estimates

FWD - 1-hr Count

Litter - Depth

CWD - Tran. Length

FWD - Tran. Length

Slash - Height

CWD - Diameter

Duff - Depth

SIMULATION CONCLUSIONS

Measurement variables whose errors least affect core table outputs: CWD decay classes, transect lengths, litter depth, and FWD counts

Measurement variables whose errors most affect core table outputs: duff depths, CWD diameter, and slash pile metrics

FIA’s Top Six LeastWanted DWM Errors

1. CWD Diameters2. FWD Counts3. Duff Depths4. Litter Depths5. Slash Compacted Height6. Sample Status/Missing Data

CWD DIAMETERS

Crews mistakenly record CWD diameters to tenth of inch…used to P2 plots

Only measure to nearest inch!!

≠

FWD COUNTS

FWD Doesn’t Account for much Biomass

However,

FWD Accounts for Much of the Flash Fuels and Fire Behavior

DUFF DEPTH

Duff is the heaviest down woody material per unit volume

Make sure your measurements (and units) are correct!

LITTER DEPTH

Much lighter than duff…however is usually much deeper

Don’t mistakenly enter the litter depth for duff depth

SLASH PILE COMPACTED HEIGHT

Transect

Compacted Height =1 ft

Potentially 1 foot of solid wood covering site

Be sure about compacted height!

Non-forest land is technically sampled…there is no DWM on it since DWM only occurs in forest conditions

Various Tiers of Sample Status…typically only snow or water can obstruct measurementTransect sample status = CWD cannot be measured nor anything else

FWD sample status = Only if snow or water obstruct

Duff/Litter sample status = Only if snow or water obstruct

APPROPRIATE USE OF SAMPLE STATUS

Situation can occur where CWD is sampled (transect sample status=1) but FWD and duff/litter cannot be sampled due to water obstruction (FWD sample status=1 and duff/litter sample status=1)

APPROPRIATE USE OF SAMPLE STATUS

Transect sample status = 0

CWD, FWD, Duff/litter not sampled

Transect sample status = 1

CWD maybe sampled

FWD and Duff/litter sample status = 0

TRAINING

PROBLEM AREAS

Problem: Field crews disturb the CWD too much trying to determine decay class or if segmentedCorrection: Although field crews must disturb CWD pieces in order to acquire measurements, try to keep disturbance to a minimum

PROBLEM AREAS

Problem: Field crews mistakenly enter extra digit for CWD diameter (40 instead of 4 inches)

Correction: Unless PDR’s catch them, be sure of very large CWD diameters

PROBLEM AREAS

If CWD piece ends in water, treat as if

underground, measure piece to

water edge

PROBLEM AREAS

Problem: Crews dig through litter hunting down pieces of FWDCorrection: Crews should only tally obvious FWD pieces, namely those on litter surfaceProblem: Crews aren’t tallying FWD pieces hung up in slash/saplings Correction: Crews should tally all FWD pieces from forest floor up to 6 feet above ground

PROBLEM AREAS

Problem: Crews either include too much of the litter layer or upper soil mineral horizons in estimation of duff depthCorrection: Crews should be absolutely sure of what is duff, litter, and mineral horizons. Be absolutely sure of duff measurements!!

PROBLEM AREAS

Duff Depths:

1) Identify duff from mineral soil2) Don’t include moss or litter

material3) Use duff/litter sample method

code to indicate if you measured or estimated duff/litter

ORGANIZING TRAINING SESSION

1) Part 1: Introduction to DWM2) Part 2: Field Methods3) Part 3: Improving DWM Data

Quality4) Certification Test

1) Stations (test optional)2) Go over one subplot together as group3) Trainees do at least one subplot on

their own – hot audit and/or compare results

Classroom

Field

BRINGING IT ALL TOGETHER

1) Pick training location where many conditions classes and sampling scenarios exist (see word file)

2) Use powerpoint files to sculpt training session so trainees have understanding of why we need quality DWM data, what we use it for, the theory behind the sampling design, field methods, and problem areas

3) Setting up a quality station course can reduce questions during actual field season – may conduct test

SAMPLE DESIGN CHANGES

The DWM Indicator must be responsive to customer needs and improving science/techniques…Don’t assume your ideas are insignificant, you collect the data, assume you know best and pass ideas upwards…

Submit your suggestions cwoodall@fs.fed.us

P2+ sample design very different from P3 in some aspects

We listened to field crews and dropped some infuriating measurements (e.g., fuelbed height)

However, this new protocol has not been used across country yet…

If you encounter any problem please let supervisor’s know ASAP

FINAL WORD

QUESTIONS?

Blast from past2004 National P3 TrainingPrescott, AZ