INTRODUCTION TO THE
P2+ DOWN WOODY
MATERIALS INDICATOR
Christopher Woodall
1st of 3
Part
Training
Series
OUTLINE
 Why Collect DWM data?
 What is P2+ DWM?
 What are Down Woody Materials?
 Sampling Design Theory
WHY COLLECT DWM DATA?
 Forest Structure
 Wildlife Habitat
 Fuel Loading
 Carbon Stocks
 Nutrient Cycles
FOREST STRUCTURE
 Measure structural attributes
missed by phase 2
Coarse Woody Debris
Fine Woody Debris
Litter
Duff
WILDLIFE
The DWM Inventory
describes the amount and
condition of wildlife habitat
WILDLIFE
2000
1800
1600
1200
1000
3
ft /a c re
1400
800
600
400
200
0
Il
IN
IA
KS
MI
MN
MO
NE
ND
SD
WI
S ta te
Mean estimates of CWD volumes for forests of the North Central Region
WILDLIFE
1%
6%
14%
20%
1%
33%
1 7%
68%
40%
A
B
T ra n se ct D i a m e te r (in )
3 .0 -7 .9
8 .0 -1 2 .9
1 3 .0 -1 7 .9
1 8 .0 +
De ca y Cla ss
1
2
3
4
5
Proportions of coarse woody debris pieces per acre by transect diameter
(A) and decay class (B) (1=least decayed, 5=most decayed), Indiana,
2001-2003
FUELS
1-hr
10-hr
100-hr
Total Fine Woody Debris
FIRE SCIENCE
 LANDFIRE: National Mapping of Fuel Loadings
 Fuels Management: Allocation of Fuel Management Funding
 Resource Assessments: Relationships to ownership and
management
 Forest Vegetation Simulator Fuel Estimates
CARBON STOCKS
 Climate
Negotiations
 Wood energy
policies and
availability
 Climate change
mitigation
DWM AND OTHER PLOT MEASUREMENTS
Completes inventory of trees from living, to dead, to fully
decomposed
Microplot
Sapling
Sub-plot Tree
Sub-plot
Standing
Dead
DWM Down
and Dead
FUTURE OF DWM MEASUREMENT
Declining Budgets
DWM Measurement
Critical to Numerous
Resource
Assessments
Major User Groups
Request Continued
Collection of DWM
=
A More Efficient
version of P3 DWM
aka P2+
WHAT IS DWM P2+?
Collect detailed
DWM data on a
few plots
Vs
Collect only most
important DWM
data on many plots
THEORY BEHIND P2+
 May better meet user’s needs using a “rapid”
protocol to measure most requested data items
on a “substantial” panel of plots:
 Fuel loadings (including piles)
 Carbon stocks (including fine woody debris)
 Biomass assessments
 Use QA/QC information and user/field crew
feedback to improve/remove variables
WHAT WAS DROPPED FROM PREVIOUS
P3?
 Fuelbed Depth
 All microplot measurements
 CWD end-point and length
measurements
 One transect per subplot
WHAT WAS REVISED?
 Transect locations
 Only 2 transects per subplot
 Slash piles measured along transect
 Only CWD attributes at point of
intersection measured
 Non-sampled statuses for numerous
components
BEHOLD NEW PLOT DESIGN
FWD < 0.25”&
0.26 – 0.9”
360
2
FWD 1.0 – 2.9””
180
CWD
≥ 3.00”
N
6 ft. HD.
10 ft. HD.
24 ft. HD
1
HD.=horizontal dist.
90
270
Subplot
4
225
45
315
3
135
CWD Transect
FWD Transect
Duff/Litter
Sample Points
Subplot Center
WHY THE NEW TRANSECTS?
 Avoids transect orientation bias while reducing number of
transects…imagine it as one big “Y” transect from old P3
design
360
2
180
N
Final subplot 1 transect balances
larger “Y” orientation
1
90
270
4
225
45
315
3
135
DEFINITION OF DWM STAYS THE SAME
Dead material within forests in various
stages of decay such as fallen trees,
branches, and leaf litter
The FIA program places numerous forest
ecosystem components into the DWM
Indicator
DWM COMPONENTS
Coarse
Woody
Debris
Fine
Woody
Debris
Litter
Duff
Slash
COARSE AND FINE WOODY DEBRIS
Transect Diameter
Class Name
0.00-0.24 inches
Small FWD
0.25-0.99 inches
Medium FWD
1.00-2.99 inches
Large FWD
3.00+ inches
CWD
FUEL-HOUR CLASSES
Transect
Diameter
Class Name
Hour-Class
Small FWD
1-hour
Medium FWD
10-hour
1.00-2.99
inches
Large FWD
100-hour
3.00+ inches
CWD
1000+-hour
0.00-0.24
inches
0.25-0.99
inches
DUFF AND LITTER
“dead plant material on
forest floor surface”
“unrecognizable plant parts”
SLASH/RESIDUE PILES
Piles of CWD
DWM SAMPLING THEORY
DWM Component
Sampling Design
CWD, FWD, Slash
Piles
Transect
Duff and Litter
Simple Random Sampling at
Specified Points in Sub-plot
DWM diversity requires a diversity of sampling methods
DEPTH ESTIMATES ON SUBPLOT
In order to estimate
depth of duff and litter on
a subplot…
Litter
8 sample points located for
measurement on subplots at
the end of each transect
Duff
DEPTH ESTIMATES ON SUBPLOTS
360
2
Sample Locations
180
N
1
90
270
4
225
45
315
3
135
DEPTH SAMPLING STATUS
 If point covered in snow or water it can now be indicated and
not sampled
 However, if rock or log is at point then it is sampled with
potentially no duf f/litter at location
Old P3 Calculation
P2+ Calculation
11 points with rocks = null
1 point with deep litter = 5 inches
11 points with rocks = 0
1 point with deep litter = 5 inches
Plot Average = 5 inches
Plot Average = 0.4 inches
Potentially Biased!
TRANSECT SAMPLING
FWD and CWD pieces are not all
counted within a given area
rather…
All FWD and CWD pieces that
intersect a sampling plane are tallied
TRANSECT SAMPLING
Probability of match stick
intersecting randomly
placed line related to
number of sticks and
length of line
TRANSECT SAMPLING PLANES
Intersectin g
S am pling
P lane
C W D P ieces
Fuel B ed
DWM Sample Protocol establishes sampling transects that radiate
from FIA subplot centers to intersect fine and coarse woody pieces
CWD AND FWD TRANSECTS
360
2
180
N
1
90
270
4
225
45
315
3
135
Use 2 transects
established on each
subplot to sample
CWD, one transect on
each subplot to
sample FWD
ONLY MEASURE PIECE INFORMATION AT
POINT OF INTERSECTION
Transect imaginary
sampling plane
VOLUME/BIOMASS ESTIMATION FROM
JUST TRANSECT MEASUREMENT?
We have only been using transect
diameter for fine woody debris
estimation for over a decade…now we
apply similar estimator to coarse
woody debris
 2

43560  8
yd 
144 


4
K
j
n
2
jk
Q M D I jk 
j 1 k 1
4
 L
j 1
jd 
s jd  
jkd






BRINGING IT ALL TOGETHER
FWD < 0.25”&
0.26 – 0.9”
360
2
FWD 1.0 – 2.9””
180
CWD
≥ 3.00”
N
6 ft. HD.
10 ft. HD.
24 ft. HD
1
HD.=horizontal dist.
90
270
Subplot
4
225
45
315
3
135
CWD Transect
FWD Transect
Duff/Litter
Sample Points
Subplot Center
CONCLUSIONS
• The DWM indicator estimates numerous ecosystem
components
• Data Crucial to Fire, Carbon, and Wildlife Sciences
• Integral Part of National FIA Program, Completes Tree Life
Cycle
• A variety of sampling techniques for estimation of various
DWM components
•P2+ should be more efficient and robust
QUESTIONS
Blast from Past
P3 National Training
Macon, GA
2002