The Domestication of Lebanese Native Tree Species
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THE DOMESTICATION OF LEBANESE NATIVE TREE SPECIES Dissertation Presented in Partial Fulfillment of the Requirements for the Degree Doctor of Philosophy in the Graduate School of The Ohio State University By Hala Ghassan Zahreddine, M.S. The Ohio State University 2005 Dissertation Committee: Approved by Professor Daniel Struve, Adviser Professor David Barker Professor Miller McDonald Adviser Professor Allison Snow Horticulture and Crop Sciences Graduate Program Copyright by Hala Ghassan Zahreddine 2005 ABSTRACT Native flora in Lebanon is threatened by tourist and urban development, urban expansion in the mountainous areas, political instability, over-collection of medicinal and aromatic plants, lack of legislation prohibiting over-collection from the wild, overgrazing and forest fires. Since the end of the civil war, people started to redevelop their home gardens and there has been an increased demand for landscape plants as a result of extensive reconstruction projects across the country. Lebanon’s dry summer climate has created demand for landscape plants with low water requirement. Despite Lebanon’s floristic richness, estimated at 3, 761 vascular plant species, due to its location, topography and Mediterranean climate, most taxa used in landscape are non- native. In summer 2002, face-to-face interviews were carried across the country with seventeen nursery managers. Production of woody plants from propagation to finished product does not commonly occur, although herbaceous taxa are grown locally. Most frequently, woody taxa are imported from Italian and Spanish nurseries. The nature of the Lebanese nurseries industry is to import plants, re-pot them, and re-sell the stock within a few months. There is no recent statistical database for nursery production or sales, as the government does not collect or require reporting of landscape imports or sales. Nursery managers are not aware of marketing methods for their products; the many challenges they face are plant production and marketing. ii Fertilizer and water use studies were carried out on three species native to Lebanon that have ornamental attributes: Cercis siliquastrum, Acer syriacum and Malus trilobata. The fertilizer study aimed at determining the production potential of six sources of Cercis siliquastrum, two sources of Malus trilobata and one source of Acer syriacum, by exploring their growth, N, P, K nutrient uptake efficiency and partitioning under two fertilizer rates. Two-year old seedlings were planted in 11 liters containers in a 3:1 pine bark: compost substrate and half the seedlings within each source were assigned to either 25 or 100 mg N per L from 21-3.1 P- 5.9 K (21-7-7) Peters Water Soluble Fertilizer. Seedlings of all sources of Cercis siliquastrum grown under 25 had greater dry weight than those grown at 100 mg N per L. those of Malus trilobata grown under the low fertilizer rate were taller than those grown at the high fertilizer rate. Growth of Acer syriacum was not affected by fertilizer rates. Nutrient loading occurred in Cercis and Malus plants under the high fertilizer rate, although total plant N, P, and K content was not affected by fertilizer rate. There were also significant differences in mineral nutrient uptake and nutrient use efficiencies among the seed sources of Cercis siliquastrum and Malus trilobata. Therefore, it is recommended that performance trial be carried out for individual tree collection in different sites in Lebanon. Water use of container-grown plants and the impact of fertilization on water use were studied in these species. Water use estimates were made by saturating the containers early in the morning, allowing them to drain for one hour, weighing them and re-weighing approximately five hours later. For all species, seedlings at the low fertilizer rate used more water per cm height than plants grown at the high fertilizer rate. In addition, there were differences in water use among and within seed sources of Cercis siliquastrum and Malus trilobata. Differences as great as 50 % were seen in iii Cercis siliquastrum per cm height per hour and 14 % in Malus trilobata. Water use efficient plants were selected from each species and will be asexually propagated to confirm water use efficiency. One way to preserve these species is by propagation and reintroduction into appropriate habitats. However, this requires an understanding of the species biology and environment. The relationship of nine species to the soil and climatic conditions in eight sites along an altitudinal gradient was studied. Individual species were counted and identified within transects at each site. Climatic data was collected and soil samples were taken and analyzed for soil texture, soil pH, EC, CaCO3, organic matter content and the following nutrients: Ca, Mn, Na, Fe, P, K, Cu, Mg, and Zn. Each ecosystem had a unique environment that could be described using the first two factors (70.3 % of variation) in a Factor Analysis of the six most important variables. Some species’ densities were affected by soil conditions (the first factor) while climatic conditions (the second factor) explained the densities of species. Recommendations are made for the in-situ preservation of the nine species and their ecosystems. iv This dissertation is dedicated to my fiancé Michael, my sister Lama and my parents Fatme and Ghassan for their faith in me, encouragement, support and love. Without you, the completion of this work would have been impossible. v ACKNOWLEDGMENTS I wish to place on record my sincere thanks to everyone who was of help during the fieldwork in Lebanon and to the Howlett Hall Greenhouse staff, namely Khaled Sleem, Elsa Sattout, Ibrahim Saliby, Petra Sternberg, Kurt Bresko, David Snodgrass, and Jim Vent. Deepest thanks to those who assisted me in the lab work especially Patty Sweeney. Special thanks to those who offered me help with the statistical analysis namely Dr. Struve, Mark Thorne and Dr Barker. I am grateful to the USDA for funding the ‘Bioprospection Project” which includes my PhD studies. I would like to extend my gratitude to my student academic committee namely Drs Daniel Struve, Miller McDonald, Allison Snow, David Barker, and Martin Quigley for providing scientific direction and supervision and Dr Salma Talhouk from The American University of Beirut I would like to especially thank people who offered me moral support, to you Michael for helping me in everything and making me feel like home and to you Lama, Ghassan and Fatme for bearing months of not seeing me, for me to fulfill my dream. vi VITA November 18, 1977…………………….Born- Lebanon, Beirut July 1999……………………………….B.Sc in Agriculture, American University of Beirut, Beirut, Lebanon. July 2001……………………………….M.Sc in Plant Sciences, American University of Beirut, Beirut, Lebanon. September 2001-present……………….Graduate Research Associate, The Ohio State University PUBLICATIONS Research Publication 1. Zahreddine, H.G., Struve, D. K., and Quigley, M. 2004. Growing Pinus nigra seedlings in SpinoutTM- treated containers reduces root malformation and increases growth after transplanting. Journal of Environmental Horticulture, 22 (4): 176-182. 2. Zahreddine, H; C. Clubbe, R. Baalbaki, A. Ghalayini, and S. N. Talhouk. 2004. Status of native species in threatened Mediterranean habitats: the case of Pancratium maritimum L. (sea daffodil) in Lebanon. Biological Conservation 120, 11-18. FIELDS OF STUDY MAJOR FIELD: Horticulture and Crop Sciences vii TABLE OF CONTENTS Page ABSTRACT...............................................................................................................ii DEDICATION...........................................................................................................v ACKNOWLEDGMENTS………………………………………………………… .vi VITA………………………………………………………………………………..vii LIST OF TABLES.....................................................................................................xii LIST OF FIGURES ................................................................................................ xvi Chapters: 1. Introduction ................................................................................................... …1 1.1 Background information about Lebanon ........................................... …1 1.2 Objectives of the study ...................................................................... …5 1.3 Description of the studied plant species ............................................ …6 2. Nursery survey…………………………………………………………………12 2.1 Abstract.............................................................................................. …14 2.2 Introduction ....................................................................................... …15 2.3 Materials and methods....................................................................... …16 2.4 Perceived challenges to nursery managers……………………………..26 viii 2.5 Conclusions and recommendations…………………………………….27 3. Cercis siliquastrum growth, N, P, K content, concentration, distribution and efficiency as affected by two fertilizer rates.................................................. 35 3.1 Abstract.............................................................................................. 36 3.2 Introduction ....................................................................................... 37 3.3 Materials and methods....................................................................... ...39 3.4 Results …………………………………………………………………42 3.5 Discussion……………………………………………………………....47 3.6 Conclusions………………………...…………………………………...51