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Direct Seeding for Restoring Tropical Lowland Forest Ecosystems in Southern Thailand Panitnard Tunjai A Thesis Submitted in Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy Program in Ecology and Biodiversity Walailak University 2011 Thesis Title Direct Seeding for Restoring Tropical Lowland Forest Ecosystems in Southern Thailand Author Panitnard Tunjai Major Program Ecology and Biodiversity Advisory Committee Examining Committee ....…………………………...Chairman .………….….………………Chairman (Asst. Prof. Dr. Pitiwong Tantichodok) (Asst. Prof. Dr. Chatchai Ngamraibsakul) ....…………………………Committee ....…………………………Committee (Dr. Stephen Elliot) (Asst. Prof. Dr. Pitiwong Tantichodok) ....…………………………Committee ....…………………………Committee (Asst. Prof. Dr. Shawn K. Y. Lum) (Dr. Stephen Elliot) ..…..….……………………Committee (Asst. Prof. Dr. Shawn K. Y. Lum) ...…..….……………………Committee (Asst. Prof. Dr. Sara Bumrungsri) The Graduate Committee, Doctor of Philosophy Program in Ecology and Biodiversity, School of Science, Walailak University, has approved this thesis as a partial fulfillment of the requirements for the Doctor of Philosophy Program in Ecology and Biodiversity ....………………………………………. (Asst. Prof. Dr. Pitiwong Tantichodok) Chairman of the Graduate Committee, Doctor of Philosophy Program in Ecology and Biodiversity Table of Contents Page Abstract (Thai)…………………………………………………………………….. i Abstract (English)…………………………………………………………………. iii Acknowledgements………………………………………………………………... v Table of Contents………………………………………………………………….. vii List of Tables………………………………………………………………………. ix List of Figures……………………………………………………………………... xii List of Abbreviations……………………………………………………………..... xvi Chapter 1. Introduction………………………………………………………….... 1 1.1 Tropical deforestation………………………………………..... 1 1.2 Rehabilitation and restoration of degraded forest……………... 2 1.3 Restoration techniques……………………………………….... 4 1.4 Direct seeding as a tool for forest restoration…………………. 6 1.5 Case studies of success and failure with direct seeding……….. 11 1.6 Reforestation in southern Thailand……………………………. 14 1.7 Research objectives of this study…………………………….... 17 2. Site description………………………………………………………... 20 2.1 Southern Thailand……………………………………………... 20 2.2 Study sites……………………………………………………... 22 3. Phenology of lowland tropical tree species in southern Thailand…..... 28 3.1 Introduction……………………………………………………. 28 3.2 Materials and methods……………………………………….... 30 3.3 Results…………………………………………………………. 36 3.4 Discussion……………………………………………………... 64 4. Seed characteristics and the early establishment of direct seeding….... 70 4.1 Introduction……………………………………………………. 70 4.2 Materials and methods……………………………………….... 72 4.3 Results…………………………………………………………. 77 viii Table of Contents (Continued) Page 4.4 Discussion……………………………………………………... 92 5. Factors affecting the establishment of direct-seeded seedlings……..... 96 5.1 Introduction……………………………………………………. 96 5.2 Materials and methods……………………………………….... 100 5.3 Results…………………………………………………………. 105 5.4 Discussion……………………………………………………... 125 6. Comparing field performance direct seeded and nursery-grown trees.. 132 6.1 Introduction……………………………………………………. 132 6.2 Materials and methods……………………………………….... 135 6.3 Results………………………………………………………..... 138 6.4 Discussion……………………………………………………... 155 7. Species relevance and the achievement of direct seeding…………...... 158 7.1 Introduction…………………………………………………..... 158 7.2 Materials and methods……………………………………….... 160 7.3 Results………………………………………………………..... 164 7.4 Discussion……………………………………………………... 174 8. Overall discussion…………………………………………………...... 179 8.1 Factors affecting direct seeding success……………………..... 179 8.2 Implications for efficient direct seeding technique in southern Thailand……………………………………………………….. 180 8.3 Patch dynamic after interventions on abandoned areas ……..... 185 8.4 Limitations of this study and gaps in knowledge…………….... 186 References………………………………………………………………………..... 188 Curriculum Vitae….……………………………………………………………...... 215 ix List of Tables Table Page 2.1 Soil properties in both study sites …………………………………………… 27 3.1 List of 55 species observed……………………………………………........... 32 3.2 Flowering phenology in Krabi………………………………………….......... 41 3.3 Flowering phenology in Nakhon Si Thammarat…………………………...... 43 3.4 Fruiting phenology in Krabi………………………………………………..... 45 3.5 Fruiting phenology in Nakhon Si Thammarat……………………………...... 47 4.1 List of study species, collection and storage methods in both sites………...... 75 4.2 Seed traits of species used in the study……………………………………..... 79 4.3 Means of germination and survival percentage affected by seed traits…….... 83 4.4 Mean MLD (days) influenced by seed traits………………………................ 86 4.5 Summary of seed traits and their potential to be the candidates for direct seeding……………………………………………………….......................... 88 4.6 Seed traits score of studied species………...………………………................ 89 4.7 Suitability score of studied species at one year after sowing...……................ 90 5.1 List of study species, sowing time and storage methods at both sites……...... 102 5.2 Mean percentage germination of all studied species in both field and nursery condition at Krabi…………………………………………………… 105 5.3 Mean germination percentage of all studied species in both field and nursery condition at Nakhon Si Thammarat………………………………..... 106 5.4 Overview germination and MLD of all germinated species in both field and nursery………………………………………………………………….... 107 5.5 Mean germination, MLD and establishment performance affected by different sowing time for two species that bore fruits available for both sowings………………………………………………………………………. 110 5.6 Mean germination, MLD and establishment affected by different sowing time for groups of random species that bore fruits available for each sowing………………………………………………………………………... 113 x List of Tables (Continued) Table Page 5.7 In early sowing, mean germination, MLD, establishment and growth performance affected by different management regimes for groups of random species that bore fruits available…………………………………….. 118 5.8 In late sowing, mean germination, MLD, establishment and growth performance affected by different management regimes for groups of random species that bore fruits available …………………………………... 119 5.9 Mean germination percentage and MLD of three species for seeds stored before late sowing…………………………………………………………….. 120 5.10 Mean germination percentage, MLD, establishment and growth performance in different management regimes of D. oblonga for both sowing times……………………………………………………………….... 122 5.11 Mean germination percentage, MLD, establishment and growth performance in different management regimes of D. pilosanthera of both sowing times……………………………………………………………….... 123 5.12 Mean germination percentage, MLD, establishment and growth performance in different management regimes of P. pterocarpum for both sowing times……………………………………………………………….... 124 6.1 Mean percentage of survival at the end of 1st rainy season after transplanting……………………………………………………………….... 139 6.2 Mean of growth performance between direct-seeded and nursery-grown plants at 1 year after sowing (T1) and the end of 2nd rainy season after sowing (T2)………………………………………………………………...... 141 6.3 Mean relative growth rate (MRGR) of direct-seeded and nursery-grown plants at the end of 2nd rainy season after sowing………………………...... 144 6.4 Mean of growth data, relative growth rate (MRGR) and root/shoot ratio between different nutrient supply regimes at the end of 1st rainy season after transplanting…………………………………………………………… 146 6.5 Mean dry weight and root/shoot ratio between direct-seeded and nursery- raised plants at the end of 1st rainy season after transplanting………………. 147 xi List of Tables (Continued) Table Page 6.6 Establishment and maintenance costs of direct seeding and planting through 2 years of study………………………………………………………………. 149 7.1 List of study species………………………………………………………….. 161 7.2 Mean percentage germination and establishment of early-sown species across sucessional stage, dispersal mode and fruit type…………………....... 166 7.3 Mean percentage germination and establishment of late-sown species across sucessional stage, dispersal mode and fruit type…………………………...... 167 7.4 Growth performances of early-sown species across sucessional stages, dispersal modes and fruit types………………………………………………. 169 7.5 Growth performances of late-sown species across sucessional stages, dispersal modes and fruit types…………………………………………….... 170 7.6 Mean relative growth rate (MRGR) of early-sown species………………..... 171 7.7 Mean relative growth rate (MRGR) of late-sown species…………………... 172 7.8 Suitability score of studied species in both sowing times…………............... 173 xii List of Figures Table Page 2.1 Total monthly rainfall, and mean maximum and minimum temperature at Krabi; (a) 1989-2008 and (b) 2009-2010………………………………......... 24 2.2 Total monthly rainfall, and mean maximum and minimum temperature at Nakhon Si Thammarat; (a) 1989-2008 and (b) 2009-2010………………..... 25 3.1 The proportion of subannual, annual, supraannual, and continual flowering types of observed tree species……………………………….......................... 36 3.2 Observed patterns of community flowering; (a) no. of species with flowers, and sum average of species score at (b) KB = Krabi and (c) NST = Nakhon Si Thammarat………………………………………….... 38 3.3 Observed patterns of community fruit ripening; (a) no. of species with ripe fruits, and sum average of species score at (b) KB = Krabi and (c) NST = Nakhon Si Thammarat………………………………………….... 39 3.4 List of species with