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3rd of 3 Part Training Series Christopher Woodall IMPROVING DWM P2+ DATA QUALITY.

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Presentation on theme: "3rd of 3 Part Training Series Christopher Woodall IMPROVING DWM P2+ DATA QUALITY."— Presentation transcript:

1 3rd of 3 Part Training Series Christopher Woodall IMPROVING DWM P2+ DATA QUALITY

2 OUTLINE  QA/QC Analysis  What Customers Want  Measurement Errors  Hot and Cold Checks  Top Six List of Errors  Training

3 WHAT CUSTOMERS WANT A uniform DWM sample design applied across the entire United States producing per acre estimates of fuels, carbon, and wildlife habitat

4 MEASUREMENT ERRORS  Establishing Transects  FWD Counts  Slope versus Horizontal Distances  CWD Transect Diameter  CWD Decay Class and Species  Correct Units for Duff and Litter  Sample Status for DWM components Hot checks

5 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

6 MEASUREMENT ERROR PROPAGATION Database Processing Algorithms Core Table Measurement errors have varying magnitudes of effect


8 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

9 FIA’s Top Six Least Wanted DWM Errors 1.CWD Diameters 2.FWD Counts 3.Duff Depths 4.Litter Depths 5.Slash Compacted Height 6.Sample Status/Missing Data

10 CWD DIAMETERS Crews mistakenly record CWD diameters to tenth of inch…used to P2 plots Only measure to nearest inch!! ≠

11 FWD COUNTS FWD Doesn’t Account for much Biomass However, FWD Accounts for Much of the Flash Fuels and Fire Behavior

12 DUFF DEPTH Duff is the heaviest down woody material per unit volume Make sure your measurements (and units) are correct!

13 LITTER DEPTH Much lighter than duff…however is usually much deeper Don’t mistakenly enter the litter depth for duff depth

14 SLASH PILE COMPACTED HEIGHT Transect Compacted Height = 1 ft Potentially 1 foot of solid wood covering site Be sure about compacted height!

15  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 measurement  Transect 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

16  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


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

19 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

20 PROBLEM AREAS If CWD piece ends in water, treat as if underground, measure piece to water edge

21 PROBLEM AREAS Problem: Crews dig through litter hunting down pieces of FWD Correction: Crews should only tally obvious FWD pieces, namely those on litter surface Problem: 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

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

23 PROBLEM AREAS Duff Depths: 1)Identify duff from mineral soil 2)Don’t include moss or litter material 3)Use duff/litter sample method code to indicate if you measured or estimated duff/litter

24 ORGANIZING TRAINING SESSION 1)Part 1: Introduction to DWM 2)Part 2: Field Methods 3)Part 3: Improving DWM Data Quality 4)Certification Test 1)Stations (test optional) 2)Go over one subplot together as group 3)Trainees do at least one subplot on their own – hot audit and/or compare results Classroom Field

25 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

26 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

27  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

28 QUESTIONS? Blast from past 2004 National P3 Training Prescott, AZ

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