Tree Rings Have Characteristics That Made Them an Exceptionally Source
Total Page:16
File Type:pdf, Size:1020Kb
Università degli Studi di Pisa Dipartimento di Scienze della Terra Scuola di Dottorato di Ricerca in Scienze di Base Galileo Galilei Programma di Scienze della Terra XXIII Ciclo 2008 – 2010 Dissertazione Finale Anna Coppola Dendroclimatic analysis in the Adamello-Presanella Group (Central Italian Alps) Tutore: prof. Carlo Baroni Referees: prof.M. Pelfini Co-tutore: dott. Giovanni Leonelli prof. A. Carton Direttore della Scuola prof. Fabrizio Broglia Presidente del Programma prof. Roberto Santacroce Table of contents Abstract ..................................................................................................................................... 1 1 Introduction ...................................................................................................................... 3 2 Study area .......................................................................................................................... 5 Geological lineaments ............................................................................................................ 7 Vegetation lineaments ............................................................................................................ 9 Larix decidua Mill. characteristics and distribution ............................................................ 12 Picea abies ( L.) Karst. characteristics and distribution ..................................................... 14 3 Materials and methods ................................................................................................... 16 Climate data ......................................................................................................................... 16 Tree-ring data ....................................................................................................................... 18 Field collection and sampling strategy ............................................................................. 18 Samples preparation and tree-ring measurement.............................................................. 30 Larch Bud Moth attacks correction .................................................................................. 30 Chronology development and statistics ............................................................................ 32 Climate/tree-rings relationship ............................................................................................ 35 Climatic variables reconstruction ........................................................................................ 37 Principal component analysis ........................................................................................... 39 Split sample procedure ..................................................................................................... 41 Reconstruction validation ................................................................................................. 42 Climate Reconstruction analysis ...................................................................................... 43 4 Results .............................................................................................................................. 44 Mean Site Tree-Ring Chronologies ...................................................................................... 44 Val d‘Avio ........................................................................................................................ 44 Val Presanella ................................................................................................................... 48 Val di Fumo ...................................................................................................................... 55 Val Presena ....................................................................................................................... 59 Val Malga ......................................................................................................................... 63 Chronology descriptive statistics ...................................................................................... 66 Beam sections dating results......................................................................................... 72 Climatic Analysis results ...................................................................................................... 75 Correlations with monthly mean temperatures ................................................................. 75 Correlations with monthly mean precipitations ............................................................... 81 Moving correlation function analysis ............................................................................... 82 Moving correlations with monthly mean temperatures ................................................ 82 Moving correlations with May mean temperatures .................................................. 83 Moving correlations with June mean temperatures .................................................. 86 Moving correlations with July mean temperatures .................................................. 89 Moving correlations with August mean temperatures .............................................. 92 Moving correlations with Oct-1 mean temperatures ................................................ 95 Moving correlations with Monthly mean precipitations .............................................. 98 Moving response function analysis ................................................................................ 101 June July mean temperature reconstruction ...................................................................... 107 Principal component analysis results .............................................................................. 107 Calibration verification procedure results ...................................................................... 113 Reconstruction validation results.................................................................................... 113 5 Discussion ...................................................................................................................... 129 Climate/tree-growth correlations ....................................................................................... 129 Reconstructed June-July mean temperatures ..................................................................... 130 Temperature reconstruction characteristics .................................................................... 130 Low and high frequency patterns of the JJ mean temperature reconstruction ............... 131 The “Divergence Problem” ............................................................................................... 137 6 Conclusions ................................................................................................................... 140 7 Bibliography .................................................................................................................. 142 I. Appendix 1. Dendrogeomorphological dating of a rockfall by means of traumatic resin ducts. A case study in Val Malga (Adamello-Presanella Group, Central Italian Alps) ....................................................................................................................................... 162 Introduction ........................................................................................................................ 162 Study area ........................................................................................................................... 162 Materials and methods ....................................................................................................... 163 Results ................................................................................................................................. 165 Discussion and conclusion ................................................................................................. 167 Bibliography ....................................................................................................................... 169 II. Appendix 2. List of sampled trees ............................................................................... 173 Index of figures ..................................................................................................................... 178 Index of tables ....................................................................................................................... 187 Aknowledgements ................................................................................................................. 190 Abstract Inter annual or inter decadal climate reconstructions in the subarctic region and in high-mountain environments suffer from the absence of suitable long instrumental climate records. Annual tree-rings, along with other annually resolved natural archives, are widely used as proxies in high resolution paleoclimatology. A temperature signal-loss has been reported in tree-rings width and density records from several temperature-limited environments since the mid-20th century, revealing a decreasing attitude of tree-ring parameters in tracking increasing instrumental temperatures. In this study we carried out a dendroclimatic analysis on a data set of five European larch ring-width chronologies in the Adamello-Presanella Group, in the Italian Central Alps. We intended to evaluate the dendroclimatic potential of the high-elevation conifer vegetation to be used as a climate proxy, assessing the stability over time