Growth and yield models for
improved Sitka spruce
Talk to the Timber Quality Steering Group,
Northern Research Station
by Tom Jenkins
Project manager: Forest mensuration growth and yield
11th June 2009
Growth and yield models for improved SS
• Update on the current state of development
of growth and yield models within Forest
Research
• Questions underlying the use of these for
modelling production from improved Sitka
spruce
• Wider issues
• Example output
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17/06/2009
Growth and yield models for improved SS
Where are we now?
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17/06/2009
Growth and yield models for improved SS
Growth models currently under development
•
•
•
•
•
•
•
•
•
4
Yield Lookup (Forest Yield)
M1
M3 (Dynamic Forest Yield)
M1-CCF
DSORT
ASORT
BSORT
CSORT
MOSES.
17/06/2009
Growth and yield models for improved SS
Strategic approach: ‘M-series’ model classification
Type
M1
M2
M3
M4
M5
b.
60
CO2
550
c. 120
500
50
450
100
400
40
80
N u m b e r o f tr e e s p e r h e c ta r e
S ta n d in g v o lu m e (m 3/h a )
Detail
350
To
p
he
ig 30
ht
(m
300
250
200
20
150
60
40
100
10
20
H2O
50
0
0
0 10 20 30 40 50 60 70 80 90 100110120
0
10
Age
(
)
Production
Forecasting
Decision
Support
Scenario
Analysis
Climate
Change
Impacts
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YL4
M1
20
30
40
50
60
70
Stand age (years)
80
90
100
110
120
130
140
0
0
5
10
15
20
25
30
35
40
45
DBH class (cm)
M3
MOSES
N
Growth and yield models for improved SS
Yield Lookup (Forest Yield)
•
•
•
•
•
•
•
•
6
Electronic presentation of Booklet 48
Stand-level estimates
Static yield tables
Extended to later stand ages than in Booklet 48
Includes ‘LISS’ yield tables
In final stages of development
‘Polished’ user interface
Being prepared for publication end 2009
17/06/2009
Growth and yield models for improved SS
M1 growth model
•
•
•
•
Dynamic representation of Booklet 48
Based on ‘Christie’ paradigm
Stand-level estimates
Wide range of thinning regimes
• cycle, type, intensity
•
•
•
•
•
7
Some representation of LISS
Advanced stage of development
Already in use within FC PF system
‘Dirty’ user interface
Currently no plans for publication.
17/06/2009
Growth and yield models for improved SS
Examples of M1 simulations
550
500
Booklet 48 style
Extended MT thinning
(selection)
450
400
… with 7 year cycle
350
300
250
200
150
100
Restock...?
‘ATC’ (shelterwood)
50
0
0
10
20
30
40
50
60
70
80
S t a n d a g e ( y e a r s)
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90
100
110
120
130
140
Growth and yield models for improved SS
M3 growth model (Dynamic Forest Yield)
• Dynamic representation of tree size classes
• Stand and tree level estimates
• Wide range of thinning regimes
• cycle, type, intensity
•
•
•
•
9
Some representation of spatial variation
Advanced stage of development
‘Polished’ user interface
Should be published in due course.
17/06/2009
Growth and yield models for improved SS
M3 predictions: dbh distribution
b.
Number of trees per hectare
MT thin
120
100
M3
80
B48 + DSORT
60
40
20
0
0
5
10
15
20
25
30
35
40
45
DBH class (cm )
d.
Number of trees per hectare
No thin
M3
120
B48 + DSORT
100
80
60
40
20
0
0
5
10
15
20
25
DBH class (cm )
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30
35
40
45
Growth and yield models for improved SS
Modelling improved
Sitka spruce
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17/06/2009
Growth and yield models for improved SS
• We have a number of working models of
varying sophistication
• We will however need further information in
order to appropriately apply the best of these
to improved Sitka spruce
• The necessary input assumptions will ideally
be informed by hard data…
…although it is likely that we will have to
make a number of “intelligent guesses”.
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Growth and yield models for improved SS
• The diameter distribution is likely to be
narrower in improved SS…
…but by how much?
…will the shape of the distribution change?
• Mean tree diameter may be greater at a given
age…
…but by how much?
• Because of the anticipated uniformity of the
distribution, will the upper tail contain as
many [larger diameter] trees?
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Growth and yield models for improved SS
• Will tree mortality be the same as in stands of
“traditional” origin?
(A change in mortality will affect stocking
levels, and consequently mean tree size).
• All of the above will have an effect on the
volume assortment…
…but how significant will this be in economic
terms?
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Growth and yield models for improved SS
Wider issues…
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Growth and yield models for improved SS
Wider modelling questions and issues:
• Availability
How do we best distribute interim [growth and
yield] models within Forest Research?
• Version control
How do we ensure that our researchers are
always using (and know about) the latest
available releases?
• Training seminars and web briefings
To communicate the known limitations of the
models and the key underlying assumptions.
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Growth and yield models for improved SS
Wider modelling questions and issues:
• Component Object Model (COM)
implementation.
• Application Programming Interface (API)
publication (and wider “training”).
• Future modelling requirements (e.g. outputs,
and integration)…?
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Growth and yield models for improved SS
Some example output…
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Growth and yield models for improved SS Species: Sitka spruce
50
45
24
22
20
40
18
16
Top Height (m)
35
14
12
30
10
25
8
6
20
15
10
5
0
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0
10
20
30
40
50
60
70
80
Age (years)
90
100
110
120
130
Growth and yield models for improved SS Species: Sitka spruce (New Model)
65
60
34
32
30
28
26
24
22
55
50
20
18
16
45
14
12
Top Height (m)
40
10
35
8
30
6
25
20
15
10
5
0
20
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0
20
40
60
80
100
120
Age (years)
140
160
180
200
Growth and yield models for improved SS
Some example differences (age 50)
YC12: 2.0m × 2.0m initial spacing, intermediate thinning
(N.B. main crop values, before thinning)
Age of 1st thin
Top height (m)
Trees/ha
Mean dbh (cm)
BA (m2/ha)
Mean vol (m3)
Vol (m3/ha)
Cum. vol (m3/ha)
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Existing
25
21.0
571
31
42
0.63
360
570
New
28
21.9
525
30
38
0.71
374
585
Growth and yield models for improved SS
Some example differences (age 50)
YC12: 2.0m × 2.0m initial spacing, no thinning
Top height (m)
Trees/ha
Mean dbh (cm)
BA (m2/ha)
Mean vol (m3)
Vol (m3/ha)
Mortality (%)
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Existing
21.0
1405
23
61
0.38
534
6
New
21.9
1665
23
69
0.39
650
0
Growth and yield models for improved SS
With thanks to Robert Matthews and other
members of FREG at Alice Holt.
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17/06/2009