a cumulative distribution approach to stand structure classification

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STAND STRUCTURE CLASSIFICATION A Cumulative Distribution Approach to Stand Structure Classification Craig Farnden and Ian S. Moss Western Mensurationists’ Meeting July 2, 2003

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A Cumulative Distribution Approach to Stand Structure Classification. Craig Farnden and Ian S. Moss Western Mensurationists’ Meeting July 2, 2003. Why Classify?. It helps us to organize our observations of complex systems and to learn from those observations - PowerPoint PPT Presentation

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Page 1: A Cumulative Distribution Approach to Stand Structure Classification

STAND STRUCTURE CLASSIFICATION

A Cumulative Distribution Approach to Stand Structure

ClassificationCraig Farnden and Ian S. MossWestern Mensurationists’ Meeting

July 2, 2003

Page 2: A Cumulative Distribution Approach to Stand Structure Classification

STAND STRUCTURE CLASSIFICATION

Why Classify?

It helps us to organize our observations of complex systems and to learn from those observations

It facilitates communication between individuals: a given class label infers a set of attributes that are commonly understood

Page 3: A Cumulative Distribution Approach to Stand Structure Classification

STAND STRUCTURE CLASSIFICATION

Implicit Assumptions

Recognized that:

• Stand structure is a continuum

• There are few if any obvious breaks upon which to base classes

• Perceptions of what stands should look like can seriously skew a classification (“textbook” stand structures)

Page 4: A Cumulative Distribution Approach to Stand Structure Classification

STAND STRUCTURE CLASSIFICATION

Design Criteria

• Units must be internally consistent• Units must be readily recognizable• Sufficient number of units to

facilitate interpretations• Classification must be definitive

Page 5: A Cumulative Distribution Approach to Stand Structure Classification

STAND STRUCTURE CLASSIFICATION

Design Criteria• Classification attributes should be

easy to measure or assess for general applicability

• System should be open to improvement or refinement through sub-division and/or re-fitting

• Separable with respect to diameter distributions and species composition

Page 6: A Cumulative Distribution Approach to Stand Structure Classification

STAND STRUCTURE CLASSIFICATION

The Cumulative Distribution Approach to Classification

• Current classification built on 424 sample plots

• Uses mathematical algorithm to find stands with similar structures

• Pattern recognition based on two cumulative frequency distributions:– Basal area (m2/ha)– Trees/ha

Page 7: A Cumulative Distribution Approach to Stand Structure Classification

STAND STRUCTURE CLASSIFICATION

The Cumulative Distribution Approach to Classification

0

5

10

15

20

25

30

35

40

0 10 20 30 40 50 60 70 80

Tree DBH (cm)

Bas

al A

rea

(m2 /

ha)

Page 8: A Cumulative Distribution Approach to Stand Structure Classification

STAND STRUCTURE CLASSIFICATION

The Cumulative Distribution Approach to Classification

0

500

1000

1500

2000

2500

3000

3500

4000

0 5 10 15 20 25 30

Tree DBH (cm)

Tre

es/h

a

Page 9: A Cumulative Distribution Approach to Stand Structure Classification

STAND STRUCTURE CLASSIFICATION

0

25

50

75

100

0 5 10 15 20 25 30

Tree DBH (cm)

Tre

es/h

a P

erce

nti

le

Methodology…

Page 10: A Cumulative Distribution Approach to Stand Structure Classification

STAND STRUCTURE CLASSIFICATION

0

25

50

75

100

0 5 10 15 20 25 30

Tree DBH (cm)

Tre

es/h

a P

erce

nti

le

Methodology…

Page 11: A Cumulative Distribution Approach to Stand Structure Classification

STAND STRUCTURE CLASSIFICATION

Methodology…T= ∑distance between all pairsWGij = ∑within group pairsBGij = T - WGij

Page 12: A Cumulative Distribution Approach to Stand Structure Classification

STAND STRUCTURE CLASSIFICATION

Methodology…For each possible move, calculate:

New WGij

∆BGi

Rij = Wgij/ ∆Bgi

Find Rminij

Page 13: A Cumulative Distribution Approach to Stand Structure Classification

STAND STRUCTURE CLASSIFICATION

Results

Page 14: A Cumulative Distribution Approach to Stand Structure Classification

STAND STRUCTURE CLASSIFICATION

Results

Page 15: A Cumulative Distribution Approach to Stand Structure Classification

STAND STRUCTURE CLASSIFICATION

Results - Reference Distributions

C1

C2

C3

C4

C5

C6

C7

C8

C9

C10

C11

C12

C13

C14

C15

C16

C17

0

1000

2000

3000

4000

5000

6000

7000

8000

9000

10000

0 5 10 15 20 25

Tree DBH (cm)

Tre

es/h

a

Page 16: A Cumulative Distribution Approach to Stand Structure Classification

STAND STRUCTURE CLASSIFICATION

Results - Reference Distributions

0

10

20

30

40

50

60

0 10 20 30 40 50 60 70 80 90 100

Tree DBH (cm)

C1

C2

C3

C4

C5

C6

C7

C8

C9

C10

C11

C12

C13

C14

C15

C16

C17

Basal A

rea (

m2/h

a)

Page 17: A Cumulative Distribution Approach to Stand Structure Classification

STAND STRUCTURE CLASSIFICATION

Classifying Stands

• Plot cumulative distributions and compare to reference distributions

Page 18: A Cumulative Distribution Approach to Stand Structure Classification

STAND STRUCTURE CLASSIFICATION

Classifying Stands

0

10

20

30

40

50

60

0 10 20 30 40 50 60 70 80 90 100

Tree DBH (cm)

12

13

14

15

16

17

Basal A

rea (

m2

/ha)

Page 19: A Cumulative Distribution Approach to Stand Structure Classification

STAND STRUCTURE CLASSIFICATION

Classifying Stands

• Use computer software (planned)

• Use keys in field guide

• Plot cumulative distributions and compare to reference distributions

Page 20: A Cumulative Distribution Approach to Stand Structure Classification

STAND STRUCTURE CLASSIFICATION

Classifying Stands

17

16

15

15

15

12

13

15

14

14

B40>19.5AND B20>27.5

B25>37OR B80>8

B60>5AND B10<35

B10<32.5

B0>30OR B15>26

B10>19OR B20>16

B35>12

B0>34

B40 >18

YY

Y

Y

Y

Y

Y

Y

Y

N

N

N

N

N

N

N

N

N

KEY "A"

Page 21: A Cumulative Distribution Approach to Stand Structure Classification

STAND STRUCTURE CLASSIFICATION

Classifying Stands

0

10

20

30

40

50

60

70

0 10 20 30 40 50 60 70 80 90

Tree DBH (cm)

Basal A

rea (

m2

/ha)

Page 22: A Cumulative Distribution Approach to Stand Structure Classification

STAND STRUCTURE CLASSIFICATION

Classifying Stands

• Use Air Photo Interpretation

• Plot cumulative distributions and compare to reference distributions

• Use computer software (planned)

• Use keys in field guide

Page 23: A Cumulative Distribution Approach to Stand Structure Classification

STAND STRUCTURE CLASSIFICATION

Classifying Stands

Class 14 Class 15 Class 17

Page 24: A Cumulative Distribution Approach to Stand Structure Classification

STAND STRUCTURE CLASSIFICATION

• Plot cumulative distributions and compare to reference distributions

• Use computer software (planned)

• Use keys in field guide

• Use Air Photo Interpretation

Classifying Stands

• Recognize through familiarity

Page 25: A Cumulative Distribution Approach to Stand Structure Classification

STAND STRUCTURE CLASSIFICATION

Classifying Stands

Page 26: A Cumulative Distribution Approach to Stand Structure Classification

STAND STRUCTURE CLASSIFICATION

Classifying Stands

4

6

2 12

16

Page 27: A Cumulative Distribution Approach to Stand Structure Classification

STAND STRUCTURE CLASSIFICATION

Classifying Stands14 16

Page 28: A Cumulative Distribution Approach to Stand Structure Classification

STAND STRUCTURE CLASSIFICATION

Unresolved Issues

• Number and distribution of classes

• Use of discrete point samples versus composite samples

• Class hierarchy– Species– Spatial distribution and complex– Small tree frequency

Page 29: A Cumulative Distribution Approach to Stand Structure Classification

STAND STRUCTURE CLASSIFICATION

Conclusions

• System has great potential– Enhanced resource interpretations– Enhanced treelist imputation– Enhanced broad scale prescriptive abilities

• Appears to be robust and defensible• Should be exportable with minimal

modifications• New and untested - guinea pigs required

Page 30: A Cumulative Distribution Approach to Stand Structure Classification

STAND STRUCTURE CLASSIFICATION

Documentation

Field guide and poster

Lignum Limited web site:

www.lignum.com

go to publications

Page 31: A Cumulative Distribution Approach to Stand Structure Classification

STAND STRUCTURE CLASSIFICATION

Acknowledgements

• This project was undertaken as part of the Lignum Ltd. IFPA

• Funding for this project was provided by Forestry Innovation Investment (FII), a forestry investment mechanism of the Gov’t of BC, and Forest Renewal BC