470
Ch. Korner
and "moist" often used in finer-scale distinctions of vegetation types also do
not find adequate reflection in published g-data, further restricting the
possibility of compiling gmax lists coherent with common vegetation typologies such as the one by Holdridge (1947).
22.5 Maximum Leaf Diffusive Conductances in Important Vegetation Types
Most readers familiar with leaf gas exchange parameters have the vision of a
clear separation of typical conductance values for the various types of
plants that dominate different vegetation (Korner et al. 1979; Schulze and
Hall 1982; Korner 1993). The grouping of conductance data for important
vegetation types rather than by plant morphotypes yields a surprise (Table
22.2).
Since morphotypes such as succulents, herbaceous wild plants, and
various types of cultivated plants that form the "outlayers" in morphotypebased arrays of g are relatively unimportant with respect to global land
coverage, the "nice" cascades of gmax on a morphotype basis (Korner 1993)
Table 22.2. Maximum leaf conductance (mmol m- 2 S-I, projected leaf area) in different
types of vegetation. n is the number of species for which reliable field data were available
Type of vegetation
Number of
Mean ± SD
Median a
species
Woody vegetation
la Tundra, deciduous shrubs
8
270 ± 91
Ib Tundra, evergreen shrubs
6
235 ± 127
2 Coniferous forests (mainly boreal)
26
234 ± 99
252
3 Temperate deciduous forests
22
190 ± 71
183
4a Mediterranean deciduous shrubs/trees
6
235 ± 87
4b Mediterranean evergreen shrubs/trees
35
203 ± 108
5 Eucalyptus forests
6
218 ± 124
6 Monsoonal forest (only one reference,
5
(138 ± 19)b
possibly shade plants)
7a Hot desert shrubs, drought deciduous
4
202 ± 83
7b Hot desert shrubs, evergreen
3
222 ± 86
7c Cold desert shrubs (Great Basin data
2
(177 ± 18)b
only)
8 Semi-arid subtropical/tropical shrub and
16
198 ± 58
195
woodland vegetation
9 Seasonal tropical forest
4
(211 ± 144)b
lOa Humid tropical forests
17
249 ± 133
lOb Humid tropical forests including extremes
19
280 ± 228
193
such as Tectona grandis (gmax 1043) and
Tabebuia rosea (gmax 49)
11 Mangrove
4
(168 ± 49)b
Ch. Korner
and "moist" often used in finer-scale distinctions of vegetation types also do
not find adequate reflection in published g-data, further restricting the
possibility of compiling gmax lists coherent with common vegetation typologies such as the one by Holdridge (1947).
22.5 Maximum Leaf Diffusive Conductances in Important Vegetation Types
Most readers familiar with leaf gas exchange parameters have the vision of a
clear separation of typical conductance values for the various types of
plants that dominate different vegetation (Korner et al. 1979; Schulze and
Hall 1982; Korner 1993). The grouping of conductance data for important
vegetation types rather than by plant morphotypes yields a surprise (Table
22.2).
Since morphotypes such as succulents, herbaceous wild plants, and
various types of cultivated plants that form the "outlayers" in morphotypebased arrays of g are relatively unimportant with respect to global land
coverage, the "nice" cascades of gmax on a morphotype basis (Korner 1993)
Table 22.2. Maximum leaf conductance (mmol m- 2 S-I, projected leaf area) in different
types of vegetation. n is the number of species for which reliable field data were available
Type of vegetation
Number of
Mean ± SD
Median a
species
Woody vegetation
la Tundra, deciduous shrubs
8
270 ± 91
Ib Tundra, evergreen shrubs
6
235 ± 127
2 Coniferous forests (mainly boreal)
26
234 ± 99
252
3 Temperate deciduous forests
22
190 ± 71
183
4a Mediterranean deciduous shrubs/trees
6
235 ± 87
4b Mediterranean evergreen shrubs/trees
35
203 ± 108
5 Eucalyptus forests
6
218 ± 124
6 Monsoonal forest (only one reference,
5
(138 ± 19)b
possibly shade plants)
7a Hot desert shrubs, drought deciduous
4
202 ± 83
7b Hot desert shrubs, evergreen
3
222 ± 86
7c Cold desert shrubs (Great Basin data
2
(177 ± 18)b
only)
8 Semi-arid subtropical/tropical shrub and
16
198 ± 58
195
woodland vegetation
9 Seasonal tropical forest
4
(211 ± 144)b
lOa Humid tropical forests
17
249 ± 133
lOb Humid tropical forests including extremes
19
280 ± 228
193
such as Tectona grandis (gmax 1043) and
Tabebuia rosea (gmax 49)
11 Mangrove
4
(168 ± 49)b