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1
FIA New Growth Accounting System: A State-Partner PerspectiveChris Edgar
Texas A&M Forest Service
March 20, 2014
2
What is the issue? In September 2011 FIA cautioned users not to use
data retrieval tools for net growth and removals by diameter class
At this meeting last year it was announced that FIA had implemented a new growth accounting system and that it applied to all attributes that can change between inventories
3
What questions are addressed in this talk?What GRM options are available to users?
How do the options differ among data retrieval tools?
What are some considerations for analysis using the new system?
4
What FIA tools are there?FIDOEVALIDatorEVALIDator-PC
5
Gover
nmen
t
Acade
mia
Corpo
rate
NGO
Outsid
e th
e US
Indi
vidua
ls or
unk
nown
0
5,000
10,000
15,000
20,000
25,000
30,000
FIDO EVALIDator
Us
ers
Source: FIA Fiscal Year 2012 Business Report
6
FIDO
OtherEVALIDator-
PC
EVALIDator
7
Hurricane Rita 24 Sep 2005
771,000 acres of Texas timber damaged or
affected
Hurricane Ike 13 Sep 2008
473,000 acres of Texas timber damaged or
affected
8
2005 2006 2007 2008 2009 2010 2011 2012 20130
20,000,000
40,000,000
60,000,000
80,000,000
100,000,000
120,000,000
140,000,000
160,000,000
180,000,000
Mortality on ForestlandEast Texas
Insect Disease Fire Animal Weather Vegetation Unknown/other
Evaluation
Mil
lio
n c
ub
ic f
eet
per
yea
r
9
2006 2007 2008 2009 2010 2011 20120
500
1,000
1,500
2,000
2,500
3,000
3,500
4,000
Plot Measurement
Before Rita After Rita - Before Ike After Ike
Evaluation
Nu
mb
er o
f p
lots
10
Net growth – total Data Retrieval Tool Cubic feet per year
FIDO 693,255,597
EVALIDator-PC 693,255,603
EVALIDator
Accounting 693,328,343
Previous 693,328,343
Current 693,328,343
All live on forestland, ETX 2012
11
Net growth – totalEstimates from the various retrieval tools match
pretty well
New growth accounting system implemented in EVALIDator Temporal basis selection
Accounting, previous, current
12http://apps.fs.fed.us/Evalidator/evalidator.jsp
13
Summarizing by an attributeOften there is interest in summarizing total net
growth by an attribute made up of classesAttributes commonly used are based on a
characteristic of the plot, condition, or tree Plot – for example county or ecoregion Condition –for example owner or forest type Tree – for example species or diameter
14
Net growth – oak/hickory groupData Retrieval Tool Cubic feet per year
FIDO 63,087,704
EVALIDator-PC 63,087,704
EVALIDator
Accounting 31,825,275
Previous 66,450,351
Current 63,091,182
All live on forestland, oak/hickory forest type group, ETX 2012
15
Net growth – oak/hickory groupFIDO and EVALIDator-PC estimates match
New growth system has not been implemented in these tools
Estimate summarized based on the attribute’s current inventory value
EVALIDator-PC has some limited options for summarizing on previous inventory value Diameter class and stand-size class
16
Net growth – oak/hickory groupEVALIDator estimates vary depending on the
temporal basis selected An expected outcome because the attribute, forest type
group, can change between first measurement and second measurement
17
How much change occurred? In considering summarizing by an attribute it can
be helpful to know whether the attribute changes and how much
For condition-level attributes, run an area change retrieval in EVALIDator Row = Attribute – previous temporal basis Column = Attribute – current temporal basis
18
Current
Previous
http://apps.fs.fed.us/Evalidator/evalidator.jsp
19
Previous temporal basisGrowth on conditions typed oak/hickory at the
previous inventory (time 1) ~ 3.0 million acres total
71 percent oak/hickory group at time 2 23 percent another forest type group at time 2 6 percent classified “other” at time 2 (nonforest)
Net growth of 66.5 million cubic feet per year
20
Current temporal basisGrowth on conditions typed oak/hickory at the
current inventory (time 2) ~ 2.8 million acres total
76 percent oak/hickory group at time 1 19 percent another forest type group at time 1 5 percent classified “other” at time 1 (nonforest)
Net growth of 63.0 million cubic feet per year
21http://apps.fs.fed.us/Evalidator/evalidator.jsp
Current
Previous
22
Temporal basis considerations Interested in what happened to oak/hickory forests
This suggests previous temporal basis
Interested in what the outlook is for oak/hickory forests This suggests current temporal basis
Both estimates are valid
23
Accounting estimateAccounting estimate provides the best overall
match to net growth calculated from inventory and removals
Annual net change = Annual net growth – Annual removals
Rearrange to get
Annual net growth = Annual net change + Annual removals
24
An approximate value Inventory in oak/hickory
2007 evaluation = 3,237.6 million cu ft 2012 evaluation = 2,983.8 million cu ft Annual net change = -50.8 million cu ft
Removals in oak/hickory (previous) Annual removals = 76.8 million cu ft
Annual net growth = 26.0 million cu ft
25
Net growth – oak/hickory groupData Retrieval Tool Cubic feet per year
FIDO 63,087,704
EVALIDator-PC 63,087,704
EVALIDator
Accounting 31,825,275
Previous 66,450,351
Current 63,091,182
All live on forestland, oak/hickory forest type group, ETX 2012
Nearest to the approximate value of 26.0 million
26
Communicating with clientsNo difference on grand totalsDifferences arise when summarizing by attributes
Small differences if attribute changes infrequently Large differences if attribute changes frequently
Different resources are estimatedAll estimates are validUnderstand what resource is estimated and
whether that is what is sought
27
Thank you. Questions?
Chris Edgar
Texas A&M Forest Service
200 Technology Way, Suite 1281
College Station, TX 77845
(979) 458-6630