Aspen Crown Dieback and Mortality on the Williams Ranger District, Kaibab National Forest, Arizona
نویسنده
چکیده
....................................................................................................................... ii ACKNOWLEDGEMENTS ................................................................................................ v LIST OF TABLES ............................................................................................................ vii LIST OF FIGURES ......................................................................................................... viii PREFACE .......................................................................................................................... ix CHAPTER 1: Introduction ................................................................................................. 1 CHAPTER 2: Aspen crown dieback and mortality on the Williams Ranger District, Kaibab National Forest, Arizona ........................................................................................ 3 Introduction ................................................................................................................... 3 Methods......................................................................................................................... 7 Study Area .............................................................................................................. 7 Site Selection .......................................................................................................... 7 Tree Sampling and Measurement ........................................................................... 8 Data Analyses ....................................................................................................... 11 Results ......................................................................................................................... 14 Predisposing Site and Stand Factors ..................................................................... 14 Size Distributions .................................................................................................. 19 Contributing Damaging Agents ............................................................................ 20 Multivariate Models .............................................................................................. 24 Discussion ................................................................................................................... 26 Overstory............................................................................................................... 27 Regeneration ......................................................................................................... 30 Size Distributions .................................................................................................. 31 Diseases, Insects, and Drought ............................................................................. 32 Conclusions and Management Implications ............................................................... 33 Aspen Decline and Sudden Aspen Decline .......................................................... 33 Risk Factors .......................................................................................................... 33 Ungulates and Exclosures ..................................................................................... 35 References ................................................................................................................... 36 APPENDICES .................................................................................................................. 53
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