1 Introduction ............................................... 1
1.1 The role of forests in the global carbon cycle ............. 1
1.1.1 The global carbon cycle ............................. 1
1.1.2 Global forests and the carbon cycle ................. 3
1.1.3 The Amazon rainforest ............................... 4
1.2 Monitoring and estimating carbon budgets and fluxes of
forests across scales ...................................... 7
1.2.1 Forest inventories .................................. 9
1.2.2 Eddy covariance method ............................. 10
1.2.3 Remote sensing of vegetation ....................... 12
1.2.4 Vegetation models .................................. 15
1.3 Objectives of this thesis ................................. 20
2 Estimating the carbon fluxes of forests with an
individual-based forest model ............................. 23
2.1 Abstract .................................................. 25
2.2 Background ................................................ 25
2.3 Methods ................................................... 26
2.3.1 The study sites .................................... 26
2.3.2 The forest model FORMIND ........................... 27
2.3.3 Field data and data filtering ...................... 29
2.3.4 The model setup .................................... 30
2.4 Results ................................................... 30
2.4.1 Simulation of daily carbon fluxes at Wetzstein
forest ............................................. 30
2.4.2 Simulation of carbon fluxes at Wetzstein forest
for three different parameterizations .............. 31
2.4.3 Simulation of carbon fluxes at another spruce
forest ............................................. 32
2.4.4 Limiting factors for productivity .................. 33
2.5 Discussion ................................................ 36
2.5.1 Simulating carbon fluxes at daily and yearly time
scales ............................................. 36
2.5.2 Analyzing limiting factors for productivity with
the help of EC data ................................ 37
2.5.3 Sources of uncertainty ............................. 38
2.6 Conclusion ................................................ 39
3 spatial heterogeneity of biomass and forest structure of
the amazon rainforest: linking a forest gap model,
remote sensing and field inventory ........................ 41
3.1 Abstract .................................................. 43
3.2 Introduction .............................................. 43
3.3 Methods ................................................... 45
3.3.1 The individual-based forest gap model .............. 45
3.3.2 The regional individual-based forest gap model ..... 46
3.3.3 Large scale simulations of the Amazon rainforest ... 47
3.3.4 Linking remote sensing data and the forest gap
model to identify forest successional states ....... 47
3.3.5 Spatial resolution of the approach ................. 49
3.4 Results ................................................... 50
3.5 Discussion ................................................ 53
3.5.1 The regionalization approach ....................... 53
3.5.2 Obtained distribution of AGB in the Amazon
rainforest ......................................... 54
3.5.3 Limitations of the approach ........................ 55
3.5.4 Benefits from linking remote sensing and forest
models ............................................. 57
3.6 Conclusion ................................................ 57
4 The importance of forest structure for the estimation of
carbon fluxes in the amazon rainforest .................... 59
4.1 Abstract .................................................. 61
4.2 Introduction .............................................. 61
4.3 Methods ................................................... 63
4.3.1 An Amazon-wide individual-based forest gap model ... 63
4.3.2 Identifying the current state of the Amazon
rainforest ......................................... 65
4.3.3 Input data ......................................... 65
4.3.4 Validation ......................................... 65
4.4 Results ................................................... 66
4.4.1 Dynamics of forests in different successional
states ............................................. 66
4.4.2 Spatial distribution of GPP, wANPP and NEP at
different spatial scales ........................... 67
4.4.3 Comparison of simulation results with other flux
estimates .......................................... 69
4.4.4 Relation between analyzed carbon stocks, dynamics
and species compositions ........................... 70
4.5 Discussion ................................................ 72
4.5.1 Carbon fluxes and stocks at different
successional states ................................ 72
4.5.2 Comparison with field data and remote sensing
measurements ....................................... 73
4.5.3 Limitations of our approach ........................ 74
4.6 Conclusion ................................................ 75
5 Conclusion and outlook .................................... 77
5.1 Main results, limitations and potentials .................. 77
5.1.1 Applying a local forest gap model at the regional
scale .............................................. 77
5.1.2 Linking eddy covariance data and a forest gap
model .............................................. 80
5.1.3 Linking remote sensing data and a forest gap
model .............................................. 81
5.2 Synthesis and outlook ..................................... 83
5.2.1 The Amazon across temporal and spatial scales:
the journey continues .............................. 83
5.2.2 Large-scale simulations of other biomes ............ 83
Appendices ..................................................... 85
A Appendix of Chapter 2 ..................................... 85
Al Functional relationships .............................. 85
A2 The numerical calibration ............................. 88
A3 Nitrogen decrease in canopy ........................... 88
A4 Calculation of the maintenance respiration ............ 89
в Appendix of Chapter 3 ..................................... 90
Bl Parameterization and regionalization of FORMIND ....... 90
B2 Linking model and canopy height map ................... 96
С Appendix of Chapter 4 .................................... 106
List of Figures ............................................... 111
List of Tables ................................................ 121
List of Abbreviations ......................................... 123
Bibliography .................................................. 125
Erklärung ürber die Eigenständigkeit .......................... 153
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