Genotype by silviculture interactions on
growth, stand uniformity and leaf-level
gas exchange of loblolly pine varieties
Marco Yanez, Thomas Fox, John Seiler
Forest Productivity Cooperative Research
Priorities:
•Nutrient Availability, Fertilizer Uptake and Efficiency
•Decision Support Tools and Models
•Remote Sensing and Leaf Area Index
•Weed Control and Fertilization
•Fertilization Response
•Eucalyptus Silviculture
•Genetics X Silviculture Interactions
•Response Modeling, Growth and Yield Models
•Ecophysiology, Process Models, Potential Productivity
•Initial Spacing and Thinning
•Water and Environmental Impacts
Rationale
Silvicultural practices
Extensive
Intensity
Precision
Forest productivity
Half-sib families
Full-sib families
Tree improvement
Varieties
Rationale
Silvicultural practices
Extensive
Intensity
Precision
Forest productivity
Half-sib families
Full-sib families
Tree improvement
Varieties
Rationale
Silvicultural practices
Extensive
Intensity
Precision
Forest productivity
Half-sib families
Full-sib families
Tree improvement
Varieties
Part 1: Rationale – Stand uniformity
Variation in Clonal Performance Due to Silviculture
Low Intensity
High Intensity
Photos by Tom Fox
Part 1: Rationale – Stand uniformity
Operational, Piedmont VA
Intensive, Piedmont VA
Part 1: Rationale – Stand uniformity
Skid trail
Bedding quality
Study sites
The site at Virginia Piedmont
North Carolina Coastal Plain
9
8
7
6
5
4
3
2
1
Experimental design
VA Reynolds
NC Bladen
Operational
Intensive
Whole plot
Stand
productivity =
Sites
• 4 Varieties
• 1 OP family
• 1 CMP family
Split plot
Silvicultural + Genetic
+
entries
practices
10
11
12
13
14
15
16
17
18
27
26
25
24
23
22
21
20
19
28
29
30
31
32
33
34
35
36
45
44
43
42
41
40
39
38
37
46
47
48
49
50
51
52
53
54
63
62
61
60
59
58
57
56
55
64
65
66
67
68
69
70
71
72
9
8
7
6
5
4
3
2
1
10
11
12
13
14
15
16
17
18
27
26
25
24
23
22
21
20
19
28
29
30
31
32
33
34
35
36
45
44
43
42
41
40
39
38
37
46
47
48
49
50
51
52
53
54
63
62
61
60
59
58
57
56
55
250 tpa
500 tpa
750 tpa
Split-split plot
+
Stocking
81
80
79
78
77
76
75
74
73
Methods
Virginia Piedmont
Narrow-Crown
Broad-Crown
Clone C1 and C3
Clone C2 and C4
Part 1. Stand uniformity
Objective
To assess the effect of silviculture on stand
uniformity on loblolly pine varieties, and
To assess the stability of those responses
between different sites
Growth
100000
Stem volume (cm3)
Site x
Silvi.
80000
A
Stem volume (cm3)
B
Intensive
Operational
Intensive
Operational
60000
40000
20000
0
Site x
Gen
VA
NC
80000
60000
40000
C1
C2
C3
C4
CMP
OP
C
C1
C2
C3
C4
CMP
OP
D
20000
0
13
11 012 012
12
11 011
12 012
11
12 011 011
0
0
0
0
0
0
0
n/2 ay/2 ep/2 an/2 ay/2 ep/2 an/2 ay/2 ep/2 an/2 ay/2 ep/2 an/2
a
J
J
J
J
J
S
S
S
S
M
M
M
M
Part 1: Uniformity – DBH – Age 4
•
No effect of silviculture (p=0.054)
•
Site by genotype interaction (p<0.01)
NC
50
45
CV (%) -DBH
a
a
a
40
VA
a
a
a
a
a
a
35
ab
30
ab
b
25
20
15
10
5
0
C1
C2
C3 C4 CMP OP
Genotype
C1
C2
C3 C4 CMP OP
Genotype
Part 1: Uniformity – Height – Age 4
•
No effect of silviculture (p=0.51)
•
Site by genotype interaction (p<0.01)
NC
VA
50
45
CV (%) -Height
40
35
a
30
a
a
a
a
a
a
a
a
25
ab
20
ab
b
15
10
5
0
C1
C2
C3 C4 CMP OP
Genotype
C1
C2
C3 C4 CMP OP
Genotype
Part 1: Stand uniformity vs stand volume
DBH
Height
60
NC
VA
Regression
Vol (m3/ha)
50
NC
VA
Regression
40
30
20
10
0
0
10
20
30
40
CV (%) - DBH
50
0
10
20
30
40
CV (%) - HT
50
60
Part 2: Rationale- leaf physiology
Variation in Leaf Level Physiology Among
Varieties and Due to Silviculture
H2O
carbohydrates
CO2
Low Intensity
H2O
carbohydrates
CO2
High Intensity
Photos by Tom Fox
Part 2. Leaf-level physiology
Objective
To assess the effect of silviculture on leaf-level
physiology on loblolly pine varieties, and
To assess the stability of those responses
between different sites
Part 2: Measurements
• 3 trees/plot
• Total 108 trees/site
Sample
tree 1
9
8
7
6
5
4
3
2
1
10
11
12
13
14
15
16
17
18
27
26
25
24
23
22
21
20
19
28
29
30
31
32
33
34
35
36
45
44
43
42
41
40
39
38
37
46
47
48
49
50
51
52
53
54
63
62
61
60
59
58
57
56
55
64
65
66
67
68
69
70
71
72
81
80
79
78
77
76
75
74
73
Sample
tree 2
Sample
tree 3
Tree height
Part 2: Measurements
2011 (3rd growing season)
• Photosynthesis
• Carbon isotope discrimination
2012 (4th growing season)
Part 2: Measurements
3 fascicles
Part 2: Measurements
Asat
1600
micromol/m2/s
Results photosynthesis
Asat (micromol/m2/s)
8
A
B
7
6
5
4
3
BR
NC
VA
BR
NC
VA
2
1
0
10
20
30
Temperature (Celsius degrees)
0
1
2
VPD (kPa)
3
Part 2:
Photosynthesis
Broad
Crown
Families
Asat (micromol/m2/s)
Narrow
Crown
6.0
5.5
5.0
ab
ab
ab
a
ab
b
4.5
4.0
3.5
0.5
0.0
C1 C2 C3 C4 CMP OP
Genotype
Part 2: Carbon isotope discrimination
Carbon isotope discrimination - (‰)
NC
VA
24.0
23.5
23.0
a
a
a
a
a
a
a
ab
22.5
ab
ab
ab
b
22.0
21.5
21.0
0.0
C1 C2 C3 C4 CMP OP
C1 C2 C3 C4 CMP OP
Genotype
Genotype
Narrow Crown
Broad Crown
Families
Correlation between physiological parameters
and accumulated volume at age 4
NC
D
13
VA
HT
D
HT
∆
-0.05 ns 0.01 ns
-0.09 ns -0.01 ns
Asat
-0.37 ** -0.24 *
0.16 ns 0.22 ns
iWUE
0.31 ** 0.42 **
0.07 ns -0.07 ns
Part 3: Rationale – Within crown variation
Leaf physiology
Leaf area
Canopy conductance
N demand
Intraspecific competition
Stand dynamic
Etc.
Narrow-Crown
Broad-Crown
Clone C1 and C3
Clone C2 and C4
Part 3: Rationale – Within crown variation
Is nitrogen deficiency
expressed first in the
lower crown?
Asat
N
Low Silviculture
High Silviculture
Part 3: Rationale – Within crown variation
Asat
N
Narrow-Crown
Broad-Crown
Clone C1 and C3
Clone C2 and C4
Part 3. Leaf-level physiology ‘within crown
variation’
Objective
To assess the intra-crown variability on leaflevel physiology on loblolly pine varieties, and
Part 3: Within crown variation in Asat
Sampled tree
Tree height
Upper
Crown
Asat
Lower
Crown
N (%)
Nitrogen: Site by crown position interaction
1.8
1.6
Lower Crown
Upper Crown
**
N (%)
**
1.4
1.2
1.0
0.8
NC
VA
Silviculture
Amax (micromol/m2/s)
6.5
Lower Crown
Upper Crown
6.0
**
5.5
**
5.0
4.5
4.0
3.5
0.0
1.6
N (%)
Silv by crown position
Interaction on Asat
and N
Lower Crown
Upper Crown
**
**
1.4
1.2
1.0
0.8
Operational Intensive
Silviculture
Asat (micromol/m2/s)
6.5
Lower Crown
Upper crown
6.0
5.5
**
**
**
**
5.0
4.5
4.0
3.5
0.0
Lower Crown
Upper crown
1.6
**
N (%)
Gen by crown position
Interaction on Asat
and N
**
**
1.4
**
**
**
*
*
1.2
1.0
0.8
C1
C2
C3
C4 CMP OP
Genotype
Conclusions
Genetic by silvicultural effects on growth
(magnitude of the response was site specific).
Stand uniformity is not a trait intrinsic to varietal
stand, but higher uniformity increased stand
productivity.
Some genotypes differed in both growth and
gas-exchange parameters.
Gas exchange parameters did not explain the
differences in growth.
Implications
Differences in canopy architecture affect the
rate of canopy closure.
Differences in physiology among the genotypes
may interact with stand development to affect
forest productivity
•
Total canopy PS
•
Impact of competition on crown
development after crown closure
Differences in leaf area will affect total stand PS and
carbon capture even if leaf level PS is the same
Age 3
Narrow-Crown
Broad-Crown
Clone C1 and C3
Clone C2 and C4
Methods: Photosynthesis, part 1
Differences in leaf area will affect total stand PS and
carbon capture even if leaf level PS is the same
Age 5
Modelling efforts to predict future performance
modelling
Questions
Marco Yanez and John Peterson
setting up equipment
Photosynthesis being measured at
Bladen lakes, NC