ECOSYSTEM CARBON DYNAMICS IN LOGGED FOREST OF MALAYSIAN BORNEO Dissertation zur Erlangung der naturwissenschaftlichen Doktorwürde (Dr. sc. nat.) vorgelegt der Mathematisch-naturwissenschaftlichen Fakultät der Universität Zürich von Philippe Gérard Saner aus Beinwil (SO) Promotionskomitee: Prof. Dr. Andrew Hector (Leitung der Dissertation) Prof. Dr. Bernhard Schmid Prof. Dr. Michael Scherer-Lorenzen Dr. Simon Egli Zürich 2009 Contents Contents 1 Summary .....................................................................................................................1 2 Zusammenfassung........................................................................................................7 3 General Introduction ...................................................................................................13 3.1 Scientific background .........................................................................................................14 3.2 Thesis outline .....................................................................................................................17 3.3 References ..........................................................................................................................20 4 Chapter One ................................................................................................................23 4.1 Introduction to the Sabah Biodiversity Experiment ............................................................23 4.2 Lowland mixed dipterocarp forest ......................................................................................24 4.3 Dipterocarp ecology ...........................................................................................................25 4.4 Timber extraction ..............................................................................................................26 4.5 Forest rehabilitation ...........................................................................................................28 4.6 Malua Forest Reserve .........................................................................................................29 4.7 The abahS Biodiversity Experiment ....................................................................................33 4.7.1 Landscape, geology and soil classification ....................................................................34 4.7.2 Rainfall ........................................................................................................................35 4.8 Acknowledgement ..............................................................................................................37 4.9 References ..........................................................................................................................38 5 Chapter Two ................................................................................................................41 5.1 Carbon Baseline Estimation of the Sabah Biodiversity Experiment ....................................41 5.2 Abstract .............................................................................................................................42 5.3 Introduction ......................................................................................................................43 5.4 Material and Methods ........................................................................................................46 5.4.1 The aluaM Forest Reserve ............................................................................................46 5.4.2 The abahS Biodiversity Experiment .............................................................................46 5.4.3 Tree inventory .............................................................................................................47 5.4.4 Tree diversity ...............................................................................................................48 5.4.5 Above-ground tree biomass..........................................................................................49 5.4.6 Wood density ..............................................................................................................50 5.4.7 Above-ground non-tree biomass .................................................................................51 5.4.8 Standing litter and fine roots .......................................................................................52 5.4.9 Litterfall ......................................................................................................................52 5.4.10 Deadwood ...................................................................................................................53 5.4.11 Soil organic carbon ......................................................................................................53 5.4.12 Carbon estimation .......................................................................................................54 5.4.13 Statistical analysis and graphical presentation ..............................................................54 5.5 Results ...............................................................................................................................55 5.5.1 Tree diversity ...............................................................................................................55 5.5.2 Carbon baseline estimation .........................................................................................57 Contents 5.5.3 Above-ground tree biomass..........................................................................................57 5.5.4 Above-ground non-tree biomass ..................................................................................62 5.5.5 Litterfall ......................................................................................................................62 5.5.6 Soil organic carbon ......................................................................................................64 5.6 Discussion..........................................................................................................................65 5.6.1 Tree carbon storage ......................................................................................................65 5.6.2 Tree diversity ...............................................................................................................66 5.6.3 Carbon baseline estimation .........................................................................................68 5.7 Acknowledgment ...............................................................................................................71 5.8 Appendix ...........................................................................................................................73 5.9 References ..........................................................................................................................80 6 Chapter Three ..............................................................................................................87 6.1 Reduced Soil Respiration in Gaps in Logged Lowland Dipterocarp Forest .........................87 6.2 Abstract .............................................................................................................................88 6.3 Introduction ......................................................................................................................88 6.4 Material and Methods ........................................................................................................90 6.4.1 Site description ............................................................................................................90 6.4.2 Forest structure and composition .................................................................................91 6.4.3 Experimental set-up.....................................................................................................92 6.4.4 Measuring soil respiration ............................................................................................93 6.4.5 Measuring covariables ..................................................................................................93 6.4.6 Data analysis ...............................................................................................................94 6.5 Results ...............................................................................................................................95 6.5.1 The importance of forest composition and structure ....................................................95 6.5.2 Comparing day and night soil respiration rates ............................................................97 6.5.3 The importance of selected abiotic and biotic factors ...................................................98 6.6 Discussion..........................................................................................................................100 6.7 Conclusion ........................................................................................................................103 6.8 Acknowledgements ............................................................................................................103 6.9 References ..........................................................................................................................105 7 Chapter Four ...............................................................................................................109 7.1 Carbohydrate Allocation