Chlorophyll fluorescence measurements in Kaltenborn Experimental site

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This data is Private.

Dataset Abstract

Productivity is great in forests with a capacity to intercept incoming radiation and harness its energy efficiently. Thus, understanding the relationships between forest diversity, tree canopy biomass and photosynthetic parameters is central to predicting how diversity will affect a key ecosystem function (i.e., productivity). Specific hypotheses to be tested: I) higher tree species diversity enables greater exploitation of light within forest canopies due to niche partitioning, increasing photosynthesis and primary production (NPP); II) photosynthetic acclimation (ecological resilience to changing environmental factors) on singular species may vary according to the varying ecological conditions, but is supposed to be maintained at plot level in mixed population (interaction of different species-specific behaviors). Photosynthetic acclimation was measured with chlorophyll fluorescence, by applying fast and reliable techniques based on the fast kinetics of the chlorophyll fluorescence induction in dark adapted leaves. This method is called JIP-test and is based on the measure of the variable fluorescence at different steps of the induction. At Kaltenborn, 36 plots of 16mx16m were established in winter 2003/2004 as part of the BIOTREE project. In each plot, the area was subdivided in an unmanaged, managed and managed plus additional species. Species mixture was achieved by patch planting (patches of 8mx8m). Seedlings of four tree species were planted in a grid with two planting densities (1 m x 1.5 m for broadleaf spp. and 2 m x 1.5 m for coniferous spp.) in 36 plots. Chlorophyll fluorescence measurements (ChlF) were carried out in 15 plots, representing different mixture levels and species combinations. Sampling was done at June 23-25 2011 at Kaltenborn, where were selected 8 trees per species per plot taking in account the neighbouring tree species. ChlF measurements were replicated on 5 different leaves per tree. The measurements were done on the twigs, directly on the crown (not cutted branch) in nighttime to achieve a dark adapted of the samples in the field. In evergreen conifers ChlF measurements took in current year needles (i.e., needles sprouted in 2011, 1-year needles). Measurements were taken by PocketPEA fluorimeter (direct or prompt fluorescence).

Dataset Design

Chlorophyll fluorescence measurements were replicated on 5 different leaves per tree. The measurements were done on the twigs, directly on the crown (not cutted branch) in nighttime to achieve a dark adapted of the samples in the field. In evergreen conifers ChlF measurements took in current year needles (i.e., needles sprouted in 2011, 1-year needles).

Spatial Extent

Kaltenborn (Thuringia), Germany

Taxonomic Extent

4 tree species (total number sampled tree/specie): Fagus sylvatica (63), Quercus petraea (57), Picea abies (64), Pseudotsuga menziesii (60)

Data columns available in the raw data part of this dataset

ID plot
Kaltenborn plot number. Unique number ascribed to each plot; Datagroup description: plot number identification
Data group: Kaltenborn plot id
Values
1
12
11
10
13
Mixture level
Mixture level
Data group: Fluorescence parameters
Values
2
4
1
3
Specie combination
Name of specie combined in each mixture. Code used: PA - Picea abies; PM - Pseudotsuga menziesii; FS - Fagus sylvatica; QP - Quercus petraea
Data group: Tree species mix code
Values
FS-PM
FS-PA
FS- PM-PA
FS-PA-QP
FS
Specie
Scientific name of the trees sampled for leaf sampling (isotopic analysis, carbon and nitrogen analysis, fluorescence measurements)
Data group: Fluorescence parameters
Values
Picea abies
Quercus petraea
Fagus sylvatica
Pseudotsuga menziesii
ID tree
Number of sampled trees for leaf sampling (isotopic analysis, carbon and nitrogen analysis, fluorescence measurements)
Data group: Tree species id
Values
302
303
305
301
304
M0
Approximated initial slope (in ms-1) of the fluorescence transient normalized on the maximal variable fluorescence; Datagroup description: Approximated initial slope of the fluorescence transient
Unit: ms-1
Data group: Fluorescence parameters
Keywords: fluorescence, photosynthetic performance
Values
0.14604
0.12527999999999997
0.13613999999999998
0.14409999999999998
0.1518
VJ
Variable fluorescence intensity at time 2 millisecond after the onset of the fluorescence induction by saturating light impulse (with intensity > 3000 µmol m-2s-1). It is expressed in arbitrary unit.; Datagroup description: Variable fluorescence at 2 millisecond
Unit: a.u.
Data group: Fluorescence parameters
Keywords: fluorescence, photosynthetic performance
Values
0.28882
0.29366000000000003
0.27446
0.27991999999999995
0.29284
VI
Variable fluorescence intensity at time 30 millisecond after the onset of the fluorescence induction by saturating light impulse (with intensity > 3000 µmol m-2s-1). It is expressed in arbitrary unit.; Datagroup description: Variable fluorescence at 30 millisecond
Unit: a.u.
Data group: Fluorescence parameters
Keywords: fluorescence, photosynthetic performance
Values
0.6362399999999999
0.65788
0.6614800000000001
0.6355200000000001
0.625725
FV/FM
Maximum quantum yield of primary photochemistry in dark-adapted state. Expresses the probability that an absorbed photon will be trapped by the PSII reaction centre; Datagroup description: Maximum quantum yield of primary photochemistry in dark-adapted state
Unit: a.u.
Data group: Fluorescence parameters
Keywords: fluorescence, photosynthetic performance
Values
0.68222
0.63892
0.63576
0.65966
0.68255
Sm
Normalized area above the fluorescence induction curve. It is expressed in arbitrary unit and calculated as SM = Area/ (FM-F0), where F0 is the basl fluorescence intensity, measured at 20 microsecond after the onset of the fluorescence induction by saturating light impulse (with intensity > 3000 µmol m-2s-1).; Datagroup description: Normalized area above the fluorescence induction curve
Unit: a.u.
Data group: Fluorescence parameters
Keywords: fluorescence, photosynthetic performance
Values
23.8207
25.217466666666667
112.50630000000001
105.46237500000001
25.152820000000002
PIabs
Performance index (potential) for energy conservation from photons absorbed by PSII to the reduction of intersystem electron acceptors; Datagroup description: Performance Index (potential) from photons absorbed
Unit: a.u.
Data group: Fluorescence parameters
Keywords: fluorescence, photosynthetic performance
Values
102.14998
102.59371999999999
105.3154
103.30876
105.23686000000001
PItot
PItot is the performance index for energy conservation from photons absorbed by PSII to the reduction flux of PSI end acceptors. This parameter is calculated from other parameters of the fluorescence induction curve analysis. It is expressed in arbitrary unit.; Datagroup description: Performance Index total
Unit: a.u.
Data group: Fluorescence parameters
Keywords: fluorescence, photosynthetic performance
Values
103.85885881625123
100.28177030823687
103.48753325519311
101.9112609486075
100.24050048712748