CLIMATE TREND AND TREELINE DYNAMICS IN NEPAL HIMALAYA A THESIS SUBMITTED TO THE CENTRAL DEPARTMENT OF ENVIRONMENTAL SCIENCE INSTITUTE OF SCIENCE AND TECHNOLOGY TRIBHUVAN UNIVERSITY NEPAL FOR THE AWARD OF DOCTOR OF PHILOSOPHY IN ENVIRONMENTAL SCIENCE BY NARAYAN PRASAD GAIRE JANUARY 2016 CLIMATE TREND AND TREELINE DYNAMICS IN NEPAL HIMALAYA A THESIS SUBMITTED TO THE CENTRAL DEPARTMENT OF ENVIRONMENTAL SCIENCE INSTITUTE OF SCIENCE AND TECHNOLOGY TRIBHUVAN UNIVERSITY NEPAL FOR THE AWARD OF DOCTOR OF PHILOSOPHY IN ENVIRONMENTAL SCIENCE BY NARAYAN PRASAD GAIRE JANUARY 2016 DECLARATION Thesis entitled ―Climate trend and treeline dynamics in Nepal Himalaya‖ which is being submitted to the Central Department of Environmental Science, Institute of Science and Technology (IOST), Tribhuvan University, Nepal for the award of the degree of Doctor of Philosophy (Ph.D.), is a research work carried out by me under the supervision of Professor Dr. Madan Koirala, Central Department of Environmental Science, Tribhuvan University and co-supervision by Academician Dr. Dinesh Raj Bhuju, Nepal Academy of Science and Technology (NAST), Nepal and Associate Professor Dr. Marco Carrer, Padova University, Italy. This research is original and has not been submitted earlier in part or full in this or any other form to any university or institute, here or elsewhere, for the award of any degree. Narayan Prasad Gaire Kathmandu, Nepal ii iii iv ACKNOWLEDGEMENTS This work could not been completed successfully without the contribution of various people and organizations since I decided to work in this. I am indebted to Nepal Academy of Science and Technology (NAST) for granting me PhD fellowship and every support to conduct this research including exposure with different national and international organization. This work is a result of a team work. I would like to express my deepest gratitude to my supervisor, Professor Dr Madan Koirala, Central Department of Environmental Science, Tribhuvan University (CDES-TU), for his continuous support, inspiration and guidance throughout this study. I would like to express my deepest gratitude to my co-supervisor, Dr Dinesh Raj Bhuju, Academician, NAST, who has always been a source of inspiration and motivation to me do better and made me proficient. He has guided and supported my research work very closely since the inception of this research work, during field work to the final documentation of the research. I thank my co-supervisor, Dr Marco Carrer, Associate Professor, Padova University, Italy for his support to this work. His support and guidance during data analysis and reporting are highly appreciated. He also taught me dendrochronological tools and techniques during the inception of Dendrochronology Lab in NAST. I am grateful to Dr Santosh Kumar Shah, Scientist, Birbal Sahni Institute of Paleosciences, India, for his continuous support in analyzing and validating my data. I am indebted to earlier research scholars whose works made this study easy. Furthermore, there are several institutions that directly and indirectly helped to make this research work complete. My special thanks go to Professor Dr Kedar Rijal, head, CDES-TU for his continuous inspirational support in the research. I express my gratitude to the present and former Vice-chancellors, Secretaries, Science Faculty Chiefs, members of PhD unit including Dr. Kanti Shrestha, Iswor Prasad Khanal, Dr Bhoj Raj Pant, Dr Prakash Raut, and Shiva Prasad Upadhayaya for their continuous effort to provide me good research environment. I am indebted to whole NAST family for their continuous support during my study. I am very much indebted to CDES-TU and IOST Dean Office family, TU, for their continuous support and motivation for finishing of this research smoothly. I express sincere gratitude to DNPWC, SNP, MCA and RNP office for giving permission to conduct this work in three protected areas of Nepal. My gratitude is also for DHM for providing the essential climatic data. Fieldwork of this study is supported by different institutes. NAST provided financial support for MCA and RNP; EvK2CNR provided support for SNP and Pro Natura Fund of Japan via Dr Dinesh Raj Bhuju partially supported for RNP. Various organizations facilitated me to enhance my research capability by supporting me financially and morally to participate in trainings, workshops and conferences. My deepest gratitude and sincere thanks to CDES-TU, EFN-WWFUS, EvK2CNR, Pakistan Council for Science and Technology (PCST) and Federal Urdu University of Arts, Science and Technology (FUUAST), Pakistan; Research Institute for Humanity v and Nature (RIHN), Japan; Institute for Tibetan Plateau Research (ITP) and Third Pole Environment (TPE) Programme and Institute of Geography, Chinese Academy of Sciences, Beijing, China; Birbal Sahni Institute of Paleosciences (BSIP), Lucknow, India; Past Global Changes (PAGES); International Geosphere Biosphere Programme (IGBP); Asia Pacific Network (APN), Japan; Department of Geography of University of Minnesota, USA; Institute of Geography, Friedrich-Alexander University, Erlangen-Nurnberg, Germany. Support from Professor Dr Moinuddin Ahmed, Professor Dr Takeshi Nakatsuka, Professor Dr Achim Bräuning, Dr Masaki Sano, Dr Thorsten Kiefer, Dr Lucien Von-Gunten, Professor Dr Eryuang Liang, Dr Bimala Devkota, Dr Kumar Mainali, Professor Dr Scott Xt. George, Madan Krishna Suwal, Uday Kunwar Thapa, Laxman Pande, Yub Raj Dhakal, Dr Suman Aryal in different stages of this research and publication is highly acknowledged. Field activities are possible due to the generous support of large number of people and families. I am thankful to the local peoples and hotels of SNP, MCA and RNP who provided food and lodging during my field stay. Ms Prabina Rana provided good guidance as well as support during field work at MCA and SNP. I express my sincere thanks to Dorje Thakuri and family of Prok and villagers of Prok VDC Gorkha, Yeshi Dorje Thakuri, Chimik Hima, Norbu Samden, Norbu Lama, Lakpa, Arbindra Shrestha, Janardan Mainali, Deb Raj Sapkota and NAST's team for their support in field work in MCA; Gajendra Shrestha, Gajendra Tamang, Lakpa Dorje, Nawaraj Nepali, Mahesh Adhikari, Arjun KC, Youba Raj Pokharel in SNP; Ramesh Rokaya, Rup Raj Timilsena and Dinesh Acharya in RNP, and many anonymous persons. My colleagues and friends continuously supported me at various stages of this work. My colleagues and friends Pawan Kumar Neupane and Agni Dhakal are also a source of inspiration to which I often shared my frustrations and happiness during the work at NAST‘s lab. All thanks go to my parents, brother, brother in-law, sister, sister in-law, cousins, nieces and other relatives for their continuous inspiration, support, trust, and every investment in my academic endeavors. I would like to dedicate this work to my family who has always supported me to carry out my education and Academician Dr Dinesh Raj Bhuju who conceived idea, dreamed to initiate PhD at NAST and worked tirelessly to fulfill his dream. Narayan Prasad Gaire January 2016 vi ABSTRACT Nepal boosts good dendroclimatic potential due to diversity in topography, climate, biodiversity, and cultures. Trees at the climatic treeline can act as biomonitors and early warning signals of impacts of climate change on high altitude biota. Based on this fact and considering research gap, a dendroecological and dendroclimatological study was carried out at the treeline ecotones of three high mountain protected areas in Nepal Himalaya: Sagarmatha National Park (SNP), Manaslu Conservation Area (MCA), and Rara National Park (RNP). The study aimed (i) to determine the present position of treeline and associated tree species composition with their structure in Nepal Himalaya, (ii) to develop ring-width chronologies and analyse response of tree growth to the climatic factors, (iii) to assess dynamics of treeline in Nepal Himalaya and find out its underlying climatic factors, and (iv) to reconstruct the past climate of the region. Using vertical belt transects plots (20 m wide and variable length) detail ecological survey and dendrochronologoical study was carried out. Treeline ecotones of the study areas were formed by Abies spectabilis D. Don, Betula utilis D. Don, Juniperus recurva, Rhododendron campanulatum D. Don and Sorbus microphylla, with Salix sp. at some sites. The position of tree and species limit of the treeline forming A. spectabilis and B. utilis generally decreased from eastern to western parts of Nepal Himalaya. Regeneration of A. spectabilis was better than B. utilis in most of the sites. The size parameters such as tree density, diameter at breast height, height, and age of treeline forming A. spectabilis, and B. utilis decreased with increasing elevation which corresponded with decreasing temperatures. The spatio-temporal population age structure of these species showed both stand densification and upward shifting of the treeline in many sites. The upward shift of A. spectabilis during the past ~200 years was calculated as 0.5 to 2.6 m per year. In contrary, B. utilis changed very slowly in the past with stabilization in most sites during recent several decades. Climatic response revealed that regeneration of A. spectabilis in SNP was positively favored by high average temperature in both winter and summer, in MCA by an above-average monthly maximum temperature during most of the months and above- average precipitation during dry warm summer months, and in RNP by moist and cool year; however, regeneration-climate relationship of B. utilis