to understand growth responses to competition control treatments using ecophysiology research bill...
TRANSCRIPT
![Page 1: To understand growth responses to competition control treatments USING ECOPHYSIOLOGY RESEARCH Bill Parker – Ontario Forest Research Institute and Doug](https://reader035.vdocuments.mx/reader035/viewer/2022062802/56649eab5503460f94bb0fa4/html5/thumbnails/1.jpg)
to understand growth responses to competition control treatments
USING ECOPHYSIOLOGY RESEARCH
Bill Parker – Ontario Forest Research Institute
and
Doug Pitt – Canadian Forest Service
![Page 2: To understand growth responses to competition control treatments USING ECOPHYSIOLOGY RESEARCH Bill Parker – Ontario Forest Research Institute and Doug](https://reader035.vdocuments.mx/reader035/viewer/2022062802/56649eab5503460f94bb0fa4/html5/thumbnails/2.jpg)
Key ecological features of white pine and white spruce regeneration
• Intermediate in shade tolerance, slow initial growth
• Favoured by sheltered, moderate microenvironment
• Maximum height growth at 50% sunlight
• Maximum diameter and volume at 100% sunlight
• Weevil and blister rust damage to open grown white
pine seedlings
• Susceptibility of white spruce to spring frost damage
![Page 3: To understand growth responses to competition control treatments USING ECOPHYSIOLOGY RESEARCH Bill Parker – Ontario Forest Research Institute and Doug](https://reader035.vdocuments.mx/reader035/viewer/2022062802/56649eab5503460f94bb0fa4/html5/thumbnails/3.jpg)
Seedling microclimate Seedling physiology
• May – October
• Light (PFD), Ta, RH
• Soil moisture (SMC), Ts
• Periodic assessment
• Net photosynthesis (Pn), etc.
• Relative growth rates
![Page 4: To understand growth responses to competition control treatments USING ECOPHYSIOLOGY RESEARCH Bill Parker – Ontario Forest Research Institute and Doug](https://reader035.vdocuments.mx/reader035/viewer/2022062802/56649eab5503460f94bb0fa4/html5/thumbnails/4.jpg)
White pine restoration and shelterwood sites (ON)
1. Treatments: none (C), herbaceous only (H), woody only (W), and both (B)
2. Microclimate – growing seasons 1- 4
3. Seedling physiology – growing seasons 2- 4
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Soil moisture availability differs with treatment over time
Day of year
140 160 180 200 220 240 260 280
SMC
(%)
6
8
10
12
14
16
18
20
22
24
26
CHWB
Day of year
140 160 180 200 220 240 260 280
SMC
(%
)
6
8
10
12
14
16
18
20
22
24
26
May June July August September May June July August September
Growing season 1 Growing season 4
Restoration site
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Light availability differs with treatment over time
Years of treatment
1 2 3 4
Lig
ht
(%)
0
20
40
60
80
100
CHWB
Restoration site
Maximumheight
![Page 7: To understand growth responses to competition control treatments USING ECOPHYSIOLOGY RESEARCH Bill Parker – Ontario Forest Research Institute and Doug](https://reader035.vdocuments.mx/reader035/viewer/2022062802/56649eab5503460f94bb0fa4/html5/thumbnails/7.jpg)
Treatments affect photosynthesis through light and SMC
Light (PFD: umol m-2 s-1)
0 400 800 1200 1600 2000
Pn (u
mol
CO
2 m
-2 s
-1)
0
2
4
6
8
10
12
CHWB
SMC (%)
10 12 14 16 18
Pn (u
mol
CO
2 m
-2 s
-1)
0
2
4
6
8
10
12
r = 0.77, p < 0.0001 r = 0.50, p < 0.002
Restoration site
![Page 8: To understand growth responses to competition control treatments USING ECOPHYSIOLOGY RESEARCH Bill Parker – Ontario Forest Research Institute and Doug](https://reader035.vdocuments.mx/reader035/viewer/2022062802/56649eab5503460f94bb0fa4/html5/thumbnails/8.jpg)
Light (%)
0 20 40 60 80 100
RVR
0
30
60
90
120
150
180
CHWB
Soil heat sum
1000 1050 1100 1150 1200 1250
RH
R
1
2
3
4
5
6Restoration site
r = 0.88, p < 0.001 r = 0.67, p < 0.002
Growth driven by treatment effects on light and soil warming
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In shelterwoods, less treatment influence on soil moisture…
Day of year
120 140 160 180 200 220 240 260 280
SMC
(%)
6
8
10
12
14
16
18
20
22
24
26
Day of year
140 160 180 200 220 240 260 280
SMC
(%)
8
10
12
14
16
18
20
22
24
26
28
CHWB
May June July August September May June July August September
Growing season 1 Growing season 4
Shelterwood
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…and light due to the dominant effect of overstory on microclimate / resources
Years of treatment
1 2 3 4
Lig
ht
(%)
0
20
40
60
80CHWB
ShelterwoodMaximumheight
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Treatments affect photosynthesis through light and SMC
Light (PFD: umol m-2 s-1)
0 200 400 600 800
Pn (u
mol
CO
2 m
-2 s
-1)
1
2
3
4
5
6
7
8
CHWB
SMC (%)
10 12 14 16 18 20
Pn (u
mol
CO
2 m
-2 s
-1)
1
2
3
4
5
6
7
8r = 0.63, p < 0.001 r = 0.59, p < 0.001
Shelterwood
![Page 12: To understand growth responses to competition control treatments USING ECOPHYSIOLOGY RESEARCH Bill Parker – Ontario Forest Research Institute and Doug](https://reader035.vdocuments.mx/reader035/viewer/2022062802/56649eab5503460f94bb0fa4/html5/thumbnails/12.jpg)
Light (%)
25 30 35 40 45 50
RHR
1
2
3
4
5
6
Light (%)
25 30 35 40 45 50
RVR
0
20
40
60
80
100
120
140
CHWB
Shelterwood
r = 0.91, p < 0.0001 r = 0.85, p < 0.001
Growth driven by treatment effects on light
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Boreal mixedwood site (ON)
1. Treatments: none (C), herbaceous only (H), woody and herbaceous (B), radial woody only (RW), radial both (RB)
2. Microclimate – growing seasons 1- 4
3. Seedling physiology – growing seasons 3 - 4
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Treatments have little effect on soil moisture availability
Day of year
140 160 180 200 220 240 260 280 300
SM
C (
%)
25
30
35
40
45
50
55
60
CHBRBRW
Growing season 4
May June July August September
Boreal mixedwood
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Radial and broadcast woody control increase light levels
Year of treatment
1 2 3 4
Lig
ht
(%)
0
20
40
60
80
100
CHBRBRW
Maximumheight
Boreal mixedwood
![Page 16: To understand growth responses to competition control treatments USING ECOPHYSIOLOGY RESEARCH Bill Parker – Ontario Forest Research Institute and Doug](https://reader035.vdocuments.mx/reader035/viewer/2022062802/56649eab5503460f94bb0fa4/html5/thumbnails/16.jpg)
Treatments have little effect on photosynthesis
Years of treatment
3 4
Pn
(u
mo
l C
O 2 m
-2 s
-1)
0
1
2
3
4
5
6
7C H B RB RW
A
B
ABABAB
NS
Boreal mixedwood
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Light and humidity interact to regulate photosynthesis
Light (PFD: umol m-2 s-1)
0 500 1000 1500 2000
Pn (u
mol
CO
2 m
-2 s
-1)
0
2
4
6
8
10CHBRBRW
VPD (kPa)
0 1 2 3 4 5 6
Pn (u
mol
CO
2 m
-2 s
-1)
0
2
4
6
8
10Boreal mixedwood
r = -0.31, p < 0.00250% light
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Leaf gas exchange of white spruce is sensitive to humidity
VPD (kPa)
0 1 2 3 4 5 6
Gw
v (
mm
ol H 2O
m-2
s-1
)
0
20
40
60
80
100
120
140
160
CHBRBRW
r = -0.54, p < 0.001
Boreal mixedwood
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This response improves WUE in open environments
Light (PFD: umol m-2 s-1)
0 500 1000 1500 2000
WU
E (
um
ol C
O 2 m
ol H 2
O-1
)
0
10
20
30
40
50
60
70
80CHBRBRW
r = 0.40, p < 0.001
Boreal mixedwood
![Page 20: To understand growth responses to competition control treatments USING ECOPHYSIOLOGY RESEARCH Bill Parker – Ontario Forest Research Institute and Doug](https://reader035.vdocuments.mx/reader035/viewer/2022062802/56649eab5503460f94bb0fa4/html5/thumbnails/20.jpg)
Do competition control treatments influence spring frost damage?
Damage is dependent on:
1. Minimum air temperature
2. Light levels after frost event
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Lower temperature and higher light increase frost damage
Time
0 100 200 300 400 500 600 700
Ta (
oC)
-8
-6
-4
-2
0
2 C
H B RB RW
Time
900 1100 1300 1500 1700
Ligh
t (um
ol m
-2 s
-1)
0
400
800
1200
1600
2000June 6, 2007
Herbaceous layer presentWoody layer present
Boreal mixedwood
![Page 22: To understand growth responses to competition control treatments USING ECOPHYSIOLOGY RESEARCH Bill Parker – Ontario Forest Research Institute and Doug](https://reader035.vdocuments.mx/reader035/viewer/2022062802/56649eab5503460f94bb0fa4/html5/thumbnails/22.jpg)
White pine in clearcuts:
• Competition for light and H2O
with herbaceous and woody
vegetation
White pine in shelterwoods:
• Competition for light is most
important
Boreal mixedwood:
• Sheltered environment assists
white spruce regeneration
Thanks to all for their support!!
Conclusions