TREE WATER USE PATTERNS ARE MAINLY DRIVEN BY
ENVIRONMENTAL VARIABLES AND TREE STRUCTURAL
PARAMETERS IN HUMID TEMPERATE DECIDUOUS
HARDWOOD FORESTS
Virginia Hernandez-Santana, Heidi Asbjornsen
Presented by: Shinjini Goswami
Graduate Research Assistant
Miami University, Ohio
Contact: goswams@muohio.edu
OBJECTIVE
• To examine the short-term response of
tree water use and canopy conductance to
N and P amendments in relation to
microclimate and structural factors (tree
size and density), in three dominant tree
species in the northern deciduous
hardwood forests: A. saccharum, F.
grandifolia, and B. alleghaniensis.
MEASUREMENTS/METHODS
MEASUREMENT
WHERE
WHEN
HOW
Sap velocity measurements
BEF+HB, 4 treatments
July-Sept
HRM
Sapwood: Allometric equations
BEF, HB, Harvard Forest
August, Oct
Pressler borer
LAI: species and plot
BEF+HB, 4 treatments
Aug, Nov
Li-2200, Camera points
Water potential
BEF, 4 treatments
August (2)
Tree conductance soil-to-leaf
BEF, 4 treatments
water potential gradient
August (2)
Water pot+sap flow
July-Sept
Plot transpiration + meteo
variables
July-Sept
Ech2o probes
July-Sept
Sensors, canopy
Tree and plot water use
Canopy conductance
Penman Monteith
BEF, 4 treatments
Soil moisture
Solar radiation, vapor pressure
BEF+HB, 4 treatments, Tower BEF
deficit
RESULTS: meteorological variables
160
Accumulated daily rainfall (mm)
140
120
100
80
60
40
Accumulated daily solar radiation (MJ m-2 day-1)
20
0
35
180
220
30
240
260
280
240
260
280
240
260
280
240
260
280
DOY
25
15
10
5
0
2.0
200
220
X Data
1.5
1.0
0.5
0.0
0.5
180
Mean daily soil water content (cm3 cm-3)
Mean temperatures (20°C) slightly higher compared to
the
30-year
average
(1950-1980,
17
°C)
(http://www.pnet.sr.unh.edu/climcalc/).
20
180
Mean daily vapor pressure deficit (kPa)
200
200
220
X Data
0.4
0.3
0.2
0.1
0.0
180
200
220
C plot
N plot
P plot
N+P plot
DOY
Studied months of 2011 more humid (445 mm) than the
average for these same months (310 mm), although 31%
of the total amount of 2011 was registered the 28th of
August
RESULTS: sap velocity (nutrients+sps)
no significant differences (p>0.05)
18
20
18
Sap velocity (cm3 cm-2 h-1)
Sap velocity (cm3 cm-2 h-1)
14
12
10
8
6
12
10
8
6
4
2
2
200
180
Midday
16
-2
12
Midday
14
12
3
-2
14
3
-1
-1
Sap velocity (cm cm h )
16
Sap velocity (cm cm h )
14
4
18
Morning
16
Morning
16
10
8
6
4
2
8
6
4
2
20
0
18
10
18
0
X Data
Afternoon
16
X Data
-1
14
12
3
-2
12
Sap velocity (cm cm h )
-2
14
3
-1
Sap velocity (cm cm h )
16
10
8
6
4
2
10
8
6
4
2
0
C plot
N plot
P plot
NP plot
0
B. alleghiansis
A. saccharum
F. grandiflora
Afternoon
RESULTS: sap velocity(nutrients+sps)*DOY
30
25
C>N>P=N+P
25
Morning
Average sap velocity (cm3 cm-2 h-1)
Average sap velocity (cm3 cm-2 h-1)
Morning
20
15
10
5
300
Midday2
4
6
8
Average sap velocity (cm3 cm-2 h-1)
10
10
5
25
0
14
C plot
N plot
P plot
NP plot
0
20
15
10
5
30
0
2
4
6
8
10
12
14
Midday solar radiation (MJ m-2 h-1)
Accumulated
SM =AB< YB
B. alleghaniensis
A. saccharum
F. grandifolia
20
15
10
5
25
0
2
Afternoon
4
6
8
10
12
C>N=P=N+P
Accumulated solar radiation (MJ m-2 h-1)
25
14
C plot
N plot
P plot
NP plot
20
0
Average sap velocity (cm3 cm-2 h-1)
0
Average sap velocity (cm3 cm-2 h-1)
15
-1
Accumulated solar radiation (MJ m h )
25
12
C>N>P=N+P
-2
Average sap velocity (cm3 cm-2 h-1)
0
N.S
20
15
10
5
2
Afternoon
4
6
8
10
12
14
SM =AB< YB
Accumulated solar radiation (MJ m-2 h-1)
B. alleghaniensis
A. saccharum
F. grandifolia
20
15
10
5
0
0
0
2
4
6
8
Accumulated solar radiation (MJ m-2 h-1)
10
12
14
C plot
N plot
P plot
NP plot
0
2
4
6
8
-2
10
12
14
-1
Accumulated solar radiation (MJ m h )
B. alleghaniensis
A. saccharum
RESULTS: size effect on sap velocity and sap flow
12
y=1.7121+0.0790*x, R2=0.11, p=0.0294
7000
B. alleghiansis
A. saccharum
F. grandiflora
4
4000
3000
2000
0
12
1000
Plot C
Plot N
Plot P
Plot NP
10
DBH (cm)
100000
3
4
X Data
8
8000
Sap flow (cm h )
4
2
6000
4000
2000
0
0
10
20
30
40
50
DBH (cm)
0
12000
3
4
10
y=0.0060*x
1.7546
2
, R =0.40, p<0.0001
X Data
10000
Col 7
8000
3
-1
Sap flow (cm h )
8
Sap flow (m3h-1)
5
Midday
Col 1
Col 3
Col 5
-1
6
3
Sap velocity (cm3 cm-2 h-1)
5000
-1
3
6
2
Fig. 7.
Morning
6000
8
Sap flow (cm h )
Sap velocity (cm3 cm-2 h-1)
10
6
4
Col 9
Col 11
6000
4000
2000
2
0
0
0
10
20
30
DBH (cm)
B. alleghiansis
A. saccharum
F. grandifolia
40
50
DBH=20-30cm
DBH=30-40cm
DBH>40cm
5
Afternoon
RESULTS: transpiration and plots structure
55
3.5
50
45
-
Plot transpiration (mm day 1)
3.0
2.5
DBH (cm)
40
2.0
35
30
1.5
25
1.0
20
15
0.5
C plot
N plot
P plot
NP plot
0.0
C plot
Control
X Data
Nitrogen
Phosphorus
Nitrogen+Phosphorus
N plot
P plot
NP plot
1.0
Fraction of # stems
0.8
0.6
0.4
2D Graph 9
0.2
0.0
1.0
Fraction of sapwood
0.8
0.6
0.4
0.2
0.0
1.0
Fraction of E
0.8
0.6
0.4
0.2
0.0
DBH=18-30 cm
DBH=31-40 cm
DBH= 41-52 cm
RESULTS: transpiration and plots structure
0.14
Morning
0.12
E (mm day -1)
0.10
0.08
0.06
0.04
0.02
0.00
0.14
0
2
Midday
4
6
8
Accumulated solar radiation (MJ m-2 h-1)
0.12
10
12
14
DBH=18-30 cm
DBH=31-40 cm
DBH=41-52 cm
E (mm day -1)
0.10
0.08
0.06
0.04
0.02
0.00
0.14
0
2
Afternoon
4
6
8
Accumulated solar radiation (MJ m-2 h-1)
0.12
10
12
14
DBH=18-30 cm
DBH=31-40 cm
DBH=41-52 cm
E (mm day -1)
0.10
0.08
0.06
0.04
0.02
0.00
0
2
4
6
8
Accumulated solar radiation (MJ m-2 h-1)
10
12
14
DBH=18-30 cm
DBH=31-40 cm
DBH=41-52 cm
RESULTS: plots structure
Midday stomatal conductance (mmol m -2 s-1
600
C plot: gc=-287.4*ln(D)+596.28, R2=0.61, p<0.0001
N plot: gc=-120.94*ln(D)+234.14, R2=0.59, p<0.0001
P plot: gc=-214.04*ln(D)+405.58, R2=0.59, p<0.0001
NP plot: gc=-121.76*ln(D)+253.13, R2=0.54, p<0.0001
500
400
300
200
100
0
0.5
1.0
BEF C plot
BEF N plot
BEF P plot
BEF NP plot
1.5
2.0
Midday vapour pressure deficit (kPa)
2.5
RESULTS: plots structure
0.0
Leaf water potential (MPa)
C plot
-0.5
-1.0
-1.5
-2.0
-2.5
0.0
A. saccharum
F. grandifolia
Predawn 213
Predawn 236
Midday 213
Midday 236
-1.0
1.8
-1.5
-2.0
-2.5
0.0
B. alleghianensis
A. saccharum
F. grandifolia
P plot
Leaf water potential (MPa)
2.0
N plot
-0.5
-0.5
Predawn 213
Predawn 236
Midday 213
Midday 236
-1.0
Driving force (MPa)
Leaf water potential (MPa)
B. alleghianensis
1.6
1.4
1.2
1.0
0.8
0.6
-1.5
B. alleghianensis
A. saccharum
-2.0
DOY 213
DOY 236
-2.5
0.0
B. alleghianensis
A. saccharum
F. grandifolia
Leaf water potential (MPa)
NP plot
-0.5
Predawn 213
Predawn 236
Midday 213
Midday 236
-1.0
-1.5
-2.0
-2.5
B. alleghianensis
A. saccharum
F. grandifolia
Predawn 213
Predawn 236
Midday 213
Midday 236
F. grandifolia
CONCLUSIONS
Tree size main driver of sap velocity and whole tree water use
Tree size determines the canopy position and access to light, having a
direct effect on sap velocity. Sap velocity and tree water use closely
tied to solar radiation
Total plot transpiration controlled by sap velocity differences and local
forest characteristics such as stem density, tree size distribution and
sapwood area.
No nutrient effect found in our work. Lack of short-term effects in the
scientific literature make us think that long-term effects are possible
and future research is still needed.