Contents
XIII
12
GOTILWA: An Integrated Model
of Water Dynamics and Forest Growth
C.A. Gracia, E. Tello, S. Sabate, and J. Bellot ..................................... 163
12.1
GOTILWA: an Overview ..................................................................... 163
12.1.1 Input Data ............................................................................................ 164
12.1.2 Temporal Resolution ........................................................................... 165
12.1.3 Spatial Resolution ............................................................................... 165
12.2
Main Features and Initial Hypotheses .............................................. 166
12.3
Constant Parameters Used by GOTILWA ......................................... 168
12.3.1 Forest Structure ................................................................................... 168
12.3.2 Interception, Stemflow and Throughfall... ........................................ 168
12.3.3 Actual Evapotranspiration ................................................................. 169
12.3.4 Streamflow ........................................................................................... 169
12.3.5 Actual Transpiration ........................................................................... 169
12.3.6 Water Use Efficiency ........................................................................... 170
12.3.7 Gross Primary Production ................................................................. 170
12.3.8 Leaf Respiration .................................................................................. 171
12.3.9 Wood Respiration ............................................................................... 171
12.3.10 Fine Root Respiration ......................................................................... 171
12.3.11 Growth Respiration ............................................................................. 172
12.3.12 Net Primary Production and Carbon Allocation ............................. 172
12.4
Model Validation ................................................................................. 172
12.5
Model Application ............................................................................... 175
References ......................................................................................................... 178
Part 4 Nutrient Cycling at the Stand LeveL ........................................ 181
13
Water and Nutrient Limitations to Primary Production
F. Roda, X. Mayor, S. Sabate, and V. Diego ......................................... 183
13.1
Introduction ........................................................................................ 183
13.2
Experimental Layout .......................................................................... 184
13.3
Aboveground Net Primary Production ............................................ 184
13.4
Components of Primary Production ................................................ 185
13.4.1 Biomass Increment ............................................................................. 186
13.4.2 Litterfall. ............................................................................................... 187
13.5
Mechanisms of Response ................................................................... 187
13.5.1 Improved Water Status ....................................................................... 187
13.5.2 Increased Photosynthetic Capacity ................................................... 188
13.5.3 Increased Light Interception .............................................................. 188
13.6
Follow-up to the Experiment ............................................................. 191
13.7
Concluding Remarks .......................................................................... 192
References ......................................................................................................... 193