Sustainable Production Forestry THE JOINT FORCES OF CSIRO & SCION Development of a productivity...

Sustainable Production Forestry

THE JOINT FORCES OF CSIRO & SCION


Development of a productivity Index for Douglas-fir

Leith Knowles


Productivity Indices•Site Index (SI)SI=MTH@40years. Independent of silviculture

•Site basal Area Potential (SBAP) Derived from sample plots. The SBAP is the value that makes the growth model BA increment best match the sample plot BA increment. The overall plot mean SBAP is calculated as the period-weighted mean over all increment periods. Independent of silviculture

•Is it possible to develop one simple volume index by combining the two?


Methods

TSV=a*MTH*BA

TSV=a*SIb*SBAPc

MAI =TSV/rotation age


SI and SBAP for 1365 sample plots

y = -0.5557x + 33.26

R2 = 0.0048

0

10

20

30

40

50

0 1 2 3 4 5

SBAP (m2/ha/yr)

SI

(m @

40

yrs)


SI and SBAP matrix

min max interval Number

SI 20m 40m 4m 6

SBAP 1.0 2.4 0.2 8

48


Run SBAP SI Rot age Thin MTH Stems/ha TSV MAI

1 1 20 40 W 15 500 208 5.19

2 1.2 20 40 W 15 500 249.3 6.23

3 1.4 20 40 W 15 500 291.2 7.28

4 1.6 20 40 W 15 500 333.4 8.33

5 1.8 20 40 W 15 500 375.8 9.39

6 2 20 40 W 15 500 418.5 10.46

7 2.2 20 40 W 15 500 461.4 11.53

8 2.4 20 40 W 15 500 504.5 12.61

9 1 24 40 W 15 500 275.1 6.88

10 1.2 24 40 W 15 500 329.1 8.23

11 1.4 24 40 W 15 500 383.2 9.58

12 1.6 24 40 W 15 500 437.6 10.94

13 1.8 24 40 W 15 500 492.1 12.3

14 2 24 40 W 15 500 546.8 13.67

15 2.2 24 40 W 15 500 601.7 15.04

16 2.4 24 40 W 15 500 656.8 16.42

17 1 28 40 W 15 500 343.9 8.6

18 1.2 28 40 W 15 500 410.3 10.26

19 1.4 28 40 W 15 500 476.8 11.92

20 1.6 28 40 W 15 500 543.4 13.58

21 1.8 28 40 W 15 500 610.1 15.25

22 2 28 40 W 15 500 677 16.93

23 2.2 28 40 W 15 500 744.1 18.6

24 2.4 28 40 W 15 500 811.3 20.28

25 1 32 40 W 15 500 413.4 10.33

26 1.2 32 40 W 15 500 492.2 12.3

27 1.4 32 40 W 15 500 571 14.28

28 1.6 32 40 W 15 500 650 16.25

29 1.8 32 40 W 15 500 729.1 18.23

30 2 32 40 W 15 500 808.2 20.21

31 2.2 32 40 W 15 500 887.5 22.19

32 2.4 32 40 W 15 500 966.9 24.17

33 1 36 40 W 15 500 483.7 12.09

34 1.2 36 40 W 15 500 575.1 14.38

35 1.4 36 40 W 15 500 666.4 16.66

36 1.6 36 40 W 15 500 757.8 18.95

37 1.8 36 40 W 15 500 849.3 21.23

38 2 36 40 W 15 500 940.9 23.52

39 2.2 36 40 W 15 500 1032.6 25.81

40 2.4 36 40 W 15 500 1124.4 28.11

41 1 40 40 W 15 500 555.7 13.89

42 1.2 40 40 W 15 500 659.8 16.5

43 1.4 40 40 W 15 500 763.9 19.1

44 1.6 40 40 W 15 500 868 21.7

45 1.8 40 40 W 15 500 972.1 24.3

46 2 40 40 W 15 500 1076.4 26.91

47 2.2 40 40 W 15 500 1180.8 29.52

48 2.4 40 40 W 15 500 1285.2 32.13


What is 500 Index?

500 index is simply the predicted MAI of a stand planted at 1500 stems/ha, thinned to 500 stems/ha by 15m MTH, and grown to age 40 years


Results

500 Index = a*SIb*SBAPc

Where

a=0.0971

b=1.344

c=0.0973


500 Index compared to MAI from DF NAT

y = 0.9998x

R2 = 0.9995

0

5

10

15

20

25

30

35

0 5 10 15 20 25 30 35

MAI from DF NAT

500

Ind

ex


SBAP can be predicted from SI and 500 Index

SBAP=(500 Index/a*SIb))d

Where

a=0.0971

b=1.344

d=1.028


Sensitivity of 500 Index to changes in silviculture

Stocking @ age 10 years (1500 stems/ha)200 stems/ha=1% change in 500 Index

MTH at thinning (15m)1m=1.15% in 500 Index

Final crop stocking (500 stems/ha)100 stems/ha=6.6% in 500 Index


Latitude

Latitude a b c

380S 1.000 1.344 0.973

420S 0.097 1.344 0.973

460S 0.094 1.344 0.973


500 index can be estimated by region

Region No plots SI No plots SBAP500

Index

South Waikato 52 32.8 50 2.16 22.4

Rotorua/East Coast 467 32.8 441 1.76 18.3

Hawkes Bay 241 28.2 143 1.72 14.6

Central North Island 46 28 18 3 24.9

Lower North Island 58 29.2 19 1.58 14.1

Nelson/Marlborough 272 32.7 251 1.82 18.9

Westland 42 29.8 34 1.81 16.6

Canterbury 228 31.5 209 1.98 19.5

Otago 157 30.6 144 2.08 19.7

Southland 55 30.9 54 2.28 21.8Total NZ 1618 31.3 1363 1.88 18.4


….. and by forestRegion Forest Age No plots SI No plots SBAP 500 Index

(yrs) (m) (M2/ha/yr (M3/ha/yr)

Canterbury Blackhills 25 1 17.1

Coalgate 75 3 25.3 3 1.61 11.9

Craigieburn 27 14 28.2 14 2.54 21.4

Darfield 18 2 20.4

Geraldine 28 7 32.4 7 1.36 14

Hanmer 38 129 31 118 1.84 17.8

Peel Forest 137 1 29.7

Forest Creek 16 3 36.4 3 1.88 22.5

Ribbonwood 20 56 35.2 56 2.15 24.5

SI High Country 46 12 25.9 8 2.48 18.6

Otago Arrowtown 16 4 43.2 4 2.1 31.5

Berwick 25 33 29.1 27 1.98 17.5

Blue Mountains 39 81 31 81 2.15 20.7

Flagstaff 26 1 34.3

Herbert 32 12 28.9 12 1.86 16.3

Naseby 28 4 25.6 4 1.58 11.8

Otago Coast 27 2 34.7

Silverpeaks 30 7 24.2 6 2.01 13.9

Tokoiti 18 2 35.2 2 2.44 27.7

Luggate 20 4 34.8 4 1.72 19.4

Mt Allan 18 2 31.4 1 3.12 30.2

Ross Creek 92 1 30.7

Waipori 18 4 33.9 3 2.38 25.7

Southland Castledowns 18 17 33.6 17 2.2 23.5

Hokonui 53 9 24.5 9 2.37 16.6

Longwoods 34 28 31.4 27 2.33 22.7

Watt farm 36 1 29.6 1 1.83 16.5


Conclusions

Both SI and SBAP are needed to explain site productivity

These can be combined to predict MAI for a standard regime (500 Index)

Productivity of Douglas-fir on most sites in NZ is now expressed in terms of 500 Index

500 Index included in DF Calc V2


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