EFIMED Summer School on Do Mediterranean forests compete for water resources?. A scale approach from leaf to landscape. Chania (Greece), June 2008
Primary Production (Leaves, NPT) Carlos Gracia
Atmosphere 740 Fossil fuels 5-6
Land use change 1-2
Departament d’Ecologia, Universitat de Barcelona Centre de Recerca Ecològica i Aplicacions Forestals
50
110
Biota 550
60
The Carbon Cycle in our Planet
60 22
Rivers
70
Warm shallow waters 300
Biota 1
0.5 Soil Organic Matter 1200
2
9 10
37
80
Cold shallow waters 600
Biota 2
37
18 20
1
Intermediate and Deep Waters 34000
Sedimentation 0.5
15
Values en 10 g de C
35
(thousands of millions of tones C)
1
U
GPP, NPP and R
UNIVERSITAT DE BARCELONA
B
Respiración
Producción bruta
Producción
Producción neta Respiración
NPP = GPP - R tiempo
The Carbon balance as a result of a set of asymmetric fluxes
Rhm
Rho
Rcrf
Rmrf
Rcrg
Rmrg
Rcm
Rmm
Rcc
Rmc
Rch
Leaves
Rmh
VOCS
GPP
Hs
Ms Litterfall Coarse roots
Fine roots
Mrg Soil organic Carbon
Mrf
2
Water Use Efficiency
U UNIVERSITAT DE BARCELONA
B
Pinus sylvestris Pinus nigra
NPP
Leaves
Leaf Area Index / Leaf Biomass Turnover rate / Leaf Life Span
Fine roots
Production
Wood (Stem, Branches, Coarse roots)
Production
Leaves
Leaf Area Index / Leaf Biomass Leaf Specific Mass (LSM)
Fine roots
Biomass Turnover rate
Wood
Biomass Sapwood / Heartwood Fraction of respiring sapwood
(Stem, Branches, Coarse roots)
NPP = GPP - ΣR
Gas Exchange
Maintenance
Leaf Area Index ƒ(water available)
R Formation
GPP
The Leaf Area Index is independent of the forest structure
Tree Density (trees/ha)
Leaf Area Index
382
1.31
605
1.11
732
1.31
1560
1.32
3
U
Leaf Area Index in a Pinus sylvestris forest Montesquiu, Montesquiu, Barcelona, Spain
UNIVERSITAT DE BARCELONA
B
Maximum Leaf Area Index is limited by water availability Leaf Area Index (relative)
100 90
Total
80 70 60
Overstorey (trees)
50 40
Understorey (grasses and shrubs)
30 20 10 0 0
5
10
15
20
25
30
35
40
45
50
years after disturbances
U UNIVERSITAT DE BARCELONA
Leaf Life Span ?
B
4
1 2
3
4
5
6
7
8
Leaf Life Span and Percentage of leaf weight per year of survival 5
6
7
8
9
10
11
12
13
14
11,8 15,3 14,0 10,9 9,4
0
6,5
6,3
4,5
2,8
2,8
3,2
3,6
3,1
3,5
2,3
Pinus uncinata 10,0 14,4 14,8 13,5 9,5
7,2
4,4
3,0
2,8
3,8
5,8
4,5
3,8
2,6
P. sylvestris
28,7 27,2 16,0 8,9
5,8
4,8
4,8
3,7
Pinus nigra
27,4 32,2 20,4 10,1 6,0
3,8
0,2
Abies alba
1
2
3
4
P. halepensis 40,2 35,0 16,7 3,6
4,2
0,3
Quercus ilex
4,8
5,9
50,1 30,5 6,6
2,0
Quercus suber 61,9 19,7 5,7
11,6 1,1
Pinus pinea
2,6
50,9 37,4 9,0
Arbutus unedo 47,3 50,4 2,3
5
U
Leaf Life Span
UNIVERSITAT DE BARCELONA
B
Total data set (150) Evergreen species (55)
a Quercus ilex, Prades
b
Decidous species (69)
b
Forbs and graminoids (26)
0
500
0
1
1000 Leaf life span (days) 2
1500
3
4
5 Aerts y Chapin III, 2000
Leaf life span (years)
U UNIVERSITAT DE BARCELONA
Deciduous vs. Evergreen Species in Tropical Forests
B N (mmol m-2)
Lipí Lipíds (g m-2)
Ashes (g m-2)
Hc (kJ m-2)
Deciduous
129.4
6.3
10.4
1243.1
Evergreen
236.2
5.7
23.5
2927.6
Species
Species
Leaf Specific Mass (g dw· dw·m-2)
Cost of Construction (g glucose m-2 ) max min
Deciduous
54
88.1
86.3
Evergreen
475
698
727 Sobrado 1991
6
U UNIVERSITAT DE BARCELONA
B
Growth respiration...
How much carbohydrates are needed to synthesize 1 g of OM (i.e. 1 g of new leaves) ? Or: How much energy (kj or kcal) are needed to synthesize 1 g of OM?
Evaluación de los Impactos del Cambio Climático en España (ECCE) Ecosistemas Forestales C content in biomass (%) Broadleaved Castanea sativa Fagus sylvatica Quercus ilex Quercus suber Oaks Other Broadleaved
C content in biomass (%)
Annual uptake
0.48 0.49 0.48 0.49 0.48
627.25 2581.73 10939.85 2088.89 3929.69 2130.35
31.67 65.13 188.90 7.06 99.79 69.44
0.51 0.51 0.52 0.52 0.51 0.51 0.51 0.51
1651.06 6140.13 4733.53 456.03 1559.15 114.65 9720.72 3083.05 33.70 49789.78
32.56 233.63 154.40 25.40 52.43 5.96 272.66 60.39 1.45 1300.86
Coníferous Abies alba Pinus halepensis Pinus nigra Pinus pinaster Pinus pinea Pinus radiata Pinus sylvestris Pinus uncinata Other coniferous Total
7
U
Growth respiration...
UNIVERSITAT DE BARCELONA
B Glucose
Percentage in the composition of:
g·g-1 dw
leaf
stem
roots
A 3.18
B 5
C 2
D 2
1.92
25
10
10
Carbohydrates
1.28
52
62
56
Organic acids
0.95
5
2
2
Lignin Minerals
2.23
5
20
20
0.12
8
4
10
Lipids Proteins
Growth respiration... Glucose equiv.
Percentage in the composition of:
Cost in g of glucose/g of OM
g·g-1 dw
leaf
stem
roots
leaf
A
B
C
D
(A·B)/100
Lipids
3.18
5
2
2
.159
.064
.064
Proteins
1.92
25
10
10
.480
.192
.192
Carbohydrates
1.28
52
62
56
.666
.794
.717
Organic acids
0.95
5
2
2
.048
.019
.019
Lignin
2.23
5
20
20
,112
.446
.446
Minerals
0.12
8
4
10
.110
.005
.012
1.473
1.519
1.449
.679
.658
.690
Grams of glucose / g of dry matter Grams of organic matter /gram of invested carbohydrate
stem
roots
(A·C)/100 (A·D)/100
8
U
Energy content of OM in plant tissues
UNIVERSITAT DE BARCELONA
B
1 g C ≈ 10 kcal ≈ 41.7 kj 1 g MO ≈ 0.5 g C 1 g MO ≈ 5 kcal ≈ 20.8 kj
U UNIVERSITAT DE BARCELONA
B
Energy content of OM in trees (kj·g-1dw) hojas
ramas
tronco
Planifolios de hoja caduca (bosque templado)
20.7
20.2
19.4
Coníferas de hoja caduca (bosque templado)
20.5
---
20.2
Planifolios de hoja peremne (bosque templado)
21.8
17.9
16.9
20.7
---
19.9
17.4
---
16.7
Coníferas de hoja peremne (bosque templado) Bosque tropical
9
U
Energy content of OM in five Pinus species (kj·g-1dw)
UNIVERSITAT DE BARCELONA
B
P. sylvestris
P. radiata
P. elliottii
P. taeda
P. virginiana
> 1 año
---
---
21.8
21.5
---
del año
20.9
20.4
---
---
21.2
vivas
20.6
19.6
21.4
21.2
20.5
muertas
20.8
19.7
22.0
21.4
---
madera
20.1
19.8
21.1
20.9
19.9
corteza
---
19.1
21.6
21.6
19.7
---
21.2
---
---
21.1
acículas
ramas
tronco estróbilos piñas
19.8
20.1
---
---
---
< 5 mm
20.1
---
---
---
---
> 5 mm
15.0
---
---
---
---
raíces (Datos de Ovington 1961, Madgwick 1970, Nemeth 1972 y Madgwick et al. 1977)
U UNIVERSITAT DE BARCELONA
B
Maintenance respiration...
How much carbohydrates are needed daily to maintain 1 g of plant tissue?
10
U
Maintenance respiration: respiration: Quercus ilex leaves at Prades
UNIVERSITAT DE BARCELONA
Maintenance respiration (mgMO·gMO-1·dia-1)
B
14
Rm = 7· Q 10
12
(tª-15)/10
10 8 6 4 0
5
10
15
20
25
30
temperature ºC
U UNIVERSITAT DE BARCELONA
Efficiency in the new tissues formation: 68%
B
GPP, NPP and R
R= R growth + Rmaintenance 0.47 gOM· gOM·gOM-1
Growth respiration is almost constant and has a cost of 0.47 gOM· gOM·OM-1
4-14 mgOM· mgOM·gOM-1 d-1 Maintenance respiration is variable and it depends on temperature. temperature.
11
U UNIVERSITAT DE BARCELONA
B
GPP, NPP and R
Rmaintenance 7 mgOM·gOM-1 d-1 = 2.6 gOM·gOM-1 year-1 Empirical observations under Mediterranean conditions: to maintain 1 g de OM, 2.6 g de OM are consumed annually
C stocks and fluxes in PRADES (Quercus ilex) C Stocks (g C/m2): Leaves:
GPP (g C/m2/year):
1602
Respiration (g C/m2/year):
272
TOTAL Respiration: 1461
Branches: 1025
Aerial biomass respiration: 800
Stems:
4096
Roots:
5932
SOM:
10237
Soil Respiration:
662
Roots respiration:
209
SOM decomposition (Rhet): 453 NEE = 1602-1462 = 140
12
U UNIVERSITAT DE BARCELONA
B
Formation and maintenance cost of leaves in an evergreen tree
Leaf biomass
(g·m-2 soil)
544
Leaf Area Index
(m2 · m-2)
3.0
Leaf Specific mass
(g·m-2)
181
Mean Leaf Life
(days)*
870
Formatión Annual cost of leaves (gC·m-2 ground·year-1)
((544*0.5*365/870)/.68)
Maintenance (544*0.5*2.6)
Total
189 844 1033
* ¿Cuantas hojas se producen cada año? (????)
U UNIVERSITAT DE BARCELONA
B
Formation and maintenance cost of leaves in a deciduous tree
Leaf biomass
(g·m-2 ground)
320
Leaf Area Index
(m2 · m-2)
4.0
Leaf Specific Mass
(g·m-2)
80
Mean Leaf Life
(days)*
190
Formation ((320*0.5*1)/.68)
Annual Cost of Leaves Maintenance (gC·m-2 of ground·year-1) (320*0.5*2.6*190/365) Total
235 217 452
* ¿Cuantas hojas se producen cada año? (????)
13
U CREAF
Total Cost (gC· m-2 ground· y-1)
B
Formation
Maintenance
Total
Water mm
Leaf Biomass
189
844
1033
281
NPTissues
146
204
350
95
Fine Roots
184
95
279
76
Total
519
1143
1662
Transpiration (mm/y)
141
311
452
Precipitation (mm/y)
178
392
570
U UNIVERSITAT DE BARCELONA
B
Formation and maintenance cost of leaves in an evergreen tree
Calculate the amount of water that must be transpired by the evergreen holm oak forest to fix the carbon needed to maintain and to growth the leaves in the canopy: Assume an average WUE of 5 mmolsC/mol of water. 844 g of C/m2 = 70 mols of C 70*103 / 5= 14000 mols of water = 252 kg/m2 189 g of C/m2 = 16 mols of C 16*103 / 5= 3200 mols of water = 58 kg/m2
14
U UNIVERSITAT DE BARCELONA
B
Formation and maintenance cost of leaves in an evergreen tree
Leaves (and fine roots)are the most active component of trees. The leaf maintenance cost in natural evergreen communities is very high and much higher than the growth cost. In Mediterranean evergreens the cost of leaf requires to transpire more than 300 kg of water/m2
U UNIVERSITAT DE BARCELONA
B
Formation and maintenance cost of leaves in an evergreen tree
To be discussed in the afternoon session: What is the ecological role of the different strategies of leaf renovation: deciduous, summer deciduous, ocassional deciduous or evergreen?. Discuss… Advantages and disadvantages of being a deciduous.. Estimate the cost in terms of C and Water, of a deciduos and an evergreen common tree species in your area
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