Structure and Restoration of Natural Secondary Fore in the Central
Total Page:16
File Type:pdf, Size:1020Kb
DISSERTATION Structure and restoration of natural secondary forests in the Central Highlands, Vietnam Manh Hung Bui Faculty of Environmental Sciences, Institute of Silviculture and Forest Protection Structure and restoration of natural secondary forests in the Central Highlands, Vietnam Dissertation in fulfillment of the requirements for the Degree of Doctor of Forest Science (Dr. rer. silv.) submitted by: M.Sc. Manh Hung Bui born on 03.03.1981 in Quang Ninh, Vietnam Supervisor: Prof. Dr. habil. Sven Wagner, Dresden University of Technology Co-supervisor: Prof. Dr. Ralph Mitlöhner, University of Göttingen Reviewer: Prof. Dr. rer. nat. Uta Berger, Dresden University of Technology Date of defence: 2/12/2016 Declaration of conformity I hereby confirm that this copy conforms with the original dissertation on the topic: “Structure and restoration of natural secondary forests in the Central Highlands, Vietnam” ........................................................ Location, date ........................................................ PhD candidate’s signature Dedicated to my Son and my Big Family Acknowledgements ACKNOWLEDGEMENTS I went to Germany on a winter day and began my doctoral study in November 2013 with many difficulties. I could not speak German and was not familiar with western food and culture. My knowledge and skills were also limited. Therefore, I could not complete my study without the help, support, assistance and training of many people. It is difficult to mention all of those who have helped and supported me. It is also difficult to rank them in a certain order. From the bottom of my heart, I want to thank you all. Firstly, I would like to send special thanks to Prof. Dr. Sven Wagner (Chair of Silviculture, Institute of Silviculture and Forest protection, Faculty of Environmental Sciences, Dresden University of Technology), my first supervisor. I want to thank Professor Wagner for everything he did for me. I would like to thank him for the teaching, instructions, useful advice, support and encouragement. Thanks to Prof. Wagner for the talks which have helped me to grow up and become more useful to society. He is responsible, enthusiastic and knowledgeable. He is an excellent example for me to learn from and follow. I also want to thank Prof. Dr. Ralph Mitlöhner (Institute of Tropical Silviculture and Forest Ecology, Faculty of Forest Sciences and Forest Ecology, University of Göttingen), my co-supervisor. I want to thank him for the helpful comments and advice on my research and my dissertation. I would like to thank Prof. Dr. Uta Berger for her evaluation and her time for this dissertation. I appreciate the very kind assistance, discussions and recommendations of Dr. Franka Huth and Dr. Holger Fischer, scientific assistants of the Chair of Silviculture, in terms of silvicultural knowledge, forest restoration and scientific writing skills. Many thanks to Mrs. Claudia Engler, especially for her help on administrative procedures and paperwork. I also would like to thank Mr. Jörg Wollmerstädt and M.Sc. Richard Georgi for the very nice support related to technical work, tools and electronic devices. I also want to thank Dr. Angelika Mann and Mrs. Jana Posselt for support on administrative procedures. I would like to express my warm thanks to M.Sc. Manuela Boehme; M.Sc. Giovanna Da Ponte; M.Sc. Katharina Tiebel; M.Sc. Jan Wilkens and M.Sc. Sandy Nurvi. I also wish to send thanks to my Vietnamese friends, who are living and studying in Germany, especial those in Dresden. With their help, sharing and support, I have I Acknowledgements overcome many life and learning difficulties during my study period. I have also gained a lot of experience and lessons from them. I also want to thank James Longbotham for checking English mistakes and very nice support. I also respect and appreciate the kind support of my friends and colleagues in Kon Ka Kinh national park, Gia Lai, Vietnam. I would not have been able to finish my hard fieldwork without their help. Special thanks to Nguyen Quoc Luan, Nguyen Van Nam and Nguyen Van Toan. They were my study team members in Kon Ka Kinh national park. They tried and worked so hard under difficult conditions in the tropical forests. They have been very important and helpful to me in order to complete the data collection and all measurements in the field. Other special thanks to my wife, my son, my parents and all other family members. Their encouragement has motivated me to move forward, try to overcome the difficulties and complete my Ph.D. study program in Germany. I would like to thank Dresden University of Technology and Institute of Silviculture and Forest Protection. This is a very excellent environment for learning and doing research. I have gained a lot of knowledge and skills. I also want to thank the Vietnamese government, which has funded my study in Germany. I also would like to express thanks to the Vietnam National University of Forestry. They have given me a nice opportunity to do a Ph.D. in Germany and have generated favorable conditions for my study process. I sincerely thank the Rufford Organization and Graduate Academy of TU-Dresden. They provided financial support, especially for fieldwork and traveling costs. I am grateful to Prof. Dr. Sven Wagner, Dr. Matthew Brookhouse and Asso. Prof. Dr. Phung Van Khoa for writing recommendation letters when I applied for these funds. I want to thank you again. As I said, I would not have been able to complete my doctoral research without your help and support. I will always keep in my heart memories and images about you. I want to wish all of you lots of health, happiness and success. Thank you all very much again. Manh Hung Bui II Table of contents TABLE OF CONTENTS ACKNOWLEDGEMENTS …………………………………………… I TABLE OF CONTENTS ……………………………………………… III LIST OF FIGURES …………………………………………………… VIII LIST OF TABLES …………………………………………………….. XI LIST OF ABBREVIATIONS ………………………………………… XII SUMMARY ……………………………………………………………. XIII CHAPTER I: INTRODUCTION ……………………………………. 1 1.1. The decline of natural forest resources, orientation of difficulty and development in Vietnam ……………………………………………….. 1 1.1.1. Decline of forest resources …………………………………….. 1 1.1.2. Difficulties in forestry management ………………………….... 1 1.1.3. Management strategies ………………………………………… 2 1.2. Forest structure role ………………………………………………… 3 1.3. Forest restoration in Vietnam …………………………………… . .. 4 1.4. Importance of old-growth and secondary forests ………………….. 4 1.5. Aims, scope and hypotheses …………………………………… …. 6 1.5.1. Aims ………………………………………………………….... 6 1.5.1.1. General objective ………………………………………… . 6 1.5.1.2. Specific objective ………………………………………….. 6 1.5.2. Scope …………………………………………………………... 6 1.5.3. Hypotheses …………………………………………………….. 6 CHAPTER II: LITERATURE REVIEW …………………………… 8 2.1. Tropical forest structure analysis ………………………………….. 8 2.1.1. History …………………………………………………………. 8 2.1.1.1. Overstorey …………………………………………………. 8 2.1.1.2. Regeneration ……………………………………………….. 12 2.1.2. Structural attributes of tropical forests ………………………… 13 2.1.2.1. Overstorey …………………………………………………. 14 a. Analyzed attributes …………………………………………… . 14 b. Relevant attributes to this study …………………………. …… 15 2.1.2.2. Regeneration ………………………………………………. 21 2.2. Secondary tropical forest restoration ……………………………… 22 2.2.1. Strategies for secondary forest restoration …………………….. 23 2.2.1.1. Protection and natural recovery ……………………………. 24 2.2.1.2. Natural regeneration management …………………………. 24 a. Growing conditions and yield of desirable regeneration improvement ………………………………. …………………….. 24 b. Desirable regeneration assistance ……………… ……………... 25 III Table of contents 2.2.1.3. Accelerated Natural Regeneration (ANR) …………………. 25 2.2.1.4. Enrichment planting ………………………………………… 25 2.2.1.5. The framework species method …………………………….. 26 2.2.1.6. Maximum diversity planting method ………………………. 26 CHAPTER III: MATERIAL …………………………………………. 27 3.1. Natural conditions of the study area ……………………………….. 27 3.1.1 Geographic location, boundaries and area of Kon Ka Kinh national park ……………………………………………………………. 27 3.1.2. Topography, geology and soil …………………………………. 28 3.1.2.1. Topography ………………………………………………… 28 3.1.2.2. Geology and soil …………………………………………… 29 3.1.3. Climate and hydrology ………………………………………… 30 3.1.3.1. Climate …………………………………………………….. 30 3.1.3.2. Hydrology …………………………………………………. 31 3.2. Vegetation in Kon Ka Kinh national park ………………………… 31 3.2.1. The area of land use types …………………………………….. 31 3.2.2. Plant biodiversity ……………………………………………… 33 3.2.3. The flora and forest vegetation ………………………………... 33 3.2.3.1. Flora ……………………………………………………….. 33 3.2.3.2. Forest vegetation …………………………………………... 34 3.2.3.3. History of forest exploitation in the park ………………….. 35 3.3. Assessing the natural conditions and vegetation of the park ……… 37 3.4. Population, ethnicity and labor ……………………………………. 38 3.4.1. Population ……………………………………………………... 38 3.4.2. Labor and ethnicity ……………………………………………. 39 3.4.3. Poverty status ………………………………………………….. 40 3.5. Forest resources classification ……………………………………... 40 3.5.1. The Loeschau’s classification system ………………………….. 40 3.5.2. The relationship between forest types with development phases.. 42 CHAPTER IV: METHODOLOGY ………………………………….. 45 4.1. Plot establishment method …………………………………………. 45 4.2. Data collection method …………………………………………….. 47 4.2.1. Data collection for overstorey stem maps ……………………... 47 4.2.1.1. Tree data collection ………………………………………... 47 4.2.1.2. Tree positions ……………………………………………… 50 4.2.1.3. Gap inventory ……………………………………………… 51 4.2.2. Data collection for