Some solutions to rehabilitate the stands of Castanopsis boisii Hickel et A Camus forest in Hai Duong province Sturdent: Nguyen Minh Hien; Advisor: Bui The Doi ACKNOWLEDGEMENTS I would like to express my very great appreciation to Prof Bui The Doi from Vietnam Forestry University, my research supervisor, and Dr Nguyen Tuan Dung, my research cosupervisor, for their enthusiastic encouragement and useful critiques of this research work Without his thoughtful, patient guidance through every step of my research, this thesis could not have been realized I would like to extend my thanks to Mr Hoang Duc Luu, the Forest Management Committee of Hai Duong province for accepting the responsibility of my research in the location as well as for his useful and constructive recommendations on this project Many other people have contributed to the success of this thesis but I would like to particularly thank my parents and classmates from K57-CTTT for their support Last but not least this thesis could have never been complete without the support of Forest Resources and Environment Management Faculty of Vietnam National University of Forestry always encouraged me during the entire process of studying and doing research ABSTRACT This study was conducted to provide several biological characteristics of Castanopsis boisii such as ability to provide high nutrient food Several methods have been used to field work and data analysis The basic data analysis indicated that Castanopsis boisii stand did not only help local people reduce poverty, increase their income and living condition, but also help improve the beauty and environmental value for regional landscape According to the result analyses, I found several solutions to rehabilitate Castanopsis boisii species, followed by recommendations to effectively and sustainably develop this species in the study region TABLE OF CONTENTS ACKNOWLEDGEMENTS ABSTRACT TABLE OF CONTENTS LIST OF TABLES LIST OF FIGURES ACRONYMS INTRODUCTION CHAPTER LITERATURE REVIEW 1.1 In The World 1.2 In Vietnam 1.3 Characteristics of Castanopsis boisii 1.3.1 Morphological characteristics 1.3.2 Ecological characteristics CHAPTER STUDY GOAL, OBJECTIVES AND METHODLOGY 2.1 STUDY GOAL AND OBJECTIVES 2.1.1 Goal 2.1.2 Specific objectives 2.2 METHODLOGY 2.2.1 Secondary data collection 2.2.2 Fieldwork 2.2.3 Interview 12 2.2.4 Data analysis 13 CHAPTER OVERVIEW OF NATURAL AND SOCIAL - ECONOMIC CONDITIONSS OF STUDY SITE 14 3.1 NATURAL CONDITION 14 3.1.1 Geographical location 14 3.1.2 Topography 14 3.1.3 Climate 14 3.1.4 Hydrological 15 3.1.5 Land resources 15 3.2 SOCIAL ECONOMIC CONDITIONS 15 3.2.1 Population 15 3.2.2 Economy 16 3.2.3 Infrastructure 16 CHAPTER RESULTS AND DISCUSSION 17 4.1 Characteristics of the study site 17 4.1.1 Topography 17 4.1.2 Climate 17 4.2 Characteristics of Castanopsis boisii stand 20 4.2.1 Mature trees 20 4.2.2 Distribution of mature tree layer bases on the height and diameter 22 4.2.3 Distribution of regenerated trees bases on the height 23 4.2.4 Origin of regeneration 23 4.2.5 Shrubs vegetation 25 4.3 Castanopsis boisii stand value 26 4.3.1 Economic value of Castanopsis boisii forest in study site 26 4.3.2 Environment value and other value of Castanopsis boisii forest in study site 26 4.4 Some solutions to rehabilitate Castanopsis boisii 27 4.4.1 Adjusting the canopy cover 27 4.4.2 Adjusting the distribution of regenerated trees 28 4.4.3 Maintaining the soil moisture 28 4.4.4 The impact depending on origin of regeneration 29 CHAPTER GENERAL CONCLUSION AND FUTURE STUDY 30 5.1 Conclusion 30 5.2 Shortcomings 31 5.3 Recommendations 31 REFERENCES APPENDIX LIST OF TABLES Table 4.1: Weather data in Chi Linh Hydrometeorology forecast station (2014) 18 Table 4.2: Characteristics of mature trees in study site .20 Table 4.3: Standard deviation and coefficient of variation of H .21 Table 4.4: Standard deviation and coefficient of variation of D 1.3 .21 Table 4.5: Distribution of regeneration plant bases on the height .23 Table 4.6: Origin of regeneration trees in study site 24 Table 4.7: Characteristics of shrub vegetation in study site 25 Table 4.8: Necessary for coverage in each height levels 28 LIST OF FIGURES Figure 4.1: Comparison precipitation and evaporation in Chi Linh 2014 19 Figure 4.2: Distribution of mature tree layer bases on the height 22 Figure 4.3: Distribution of mature tree layer bases on diameter 22 Figure 4.4: The distribution of origin of regenerated trees in study site 24 ACRONYMS Notation Description Hvn Height Hunder Height under canopy D1.3 Diameter at breast height D Crown Crown diameter SE Standard Error SD Standard deviation S Coefficient of variation VNUF Vietnam National University Forestry BA1 Plot at Bac An commune BA2 Plot at Bac An commune HHT1 Plot at Hoang Hoa Tham commune HHT2 Plot at Hoang Hoa Tham commune INTRODUCTION Forest is one of the most precious resources in Vietnam, have many benefits such as disaster prevention, ecological protection, and social economic development support Forests and forest land make up to ¾ of the total area of the country [6] However, the quality and total area of forests have been declined significantly The main causes of this decline are due to forest fires and human activities (i.e slash and burn cultivation or over exploitation) Hai Duong is a province in the Red River Delta of northern Vietnam The natural area of the province encloses 1661.2 km2, which is ranked 51st in the nation Hai Duong shares its borders with six other provinces: Bac Ninh, Bac Giang, Quang Ninh in the north; Hung Yen in the west; Hai Phong in the East and Thai Ninh in the south Hai Duong has the tropical monsoon climate with typically cold winter, potentially hot summer and high humidity throughout the year Two types of wind mainly come from the South East and the North East The climate is divided into distinct seasons From early February to early April, Hai Duong has more rain due to the transition from dry season to rainy season Rainy season lasts from April to October In Hai Duong, the annual average rainfall is from 1,300 to 1,700 mm; the average temperature is approximately 23.3 oC; and the relative humidity average is around 85 - 87% Castanopsis boisii (Dẻ Ăn Quả) belongs to Fagaceae, a native species with many benefits such as wood for construction and furniture, In addition, it also provides high nutrient food In Vietnam, Castanopsis boisii can be typically found in Quang Ninh, Nghe An, Bac Giang and Hai Duong Hai Duong province has 11263.97 of forested area, in which protection forest accounts for 4683.74 ha, production forest accounts for 5036.95 ha, and special-use forest accounts for 1543.28 Chi Linh commune has the largest area of Castanopsis boisii forest with more than 2000 which is mainly concentrated in Bac An and Hoang Hoa Tham communes APPENDIX Some pictures in field work: 33 The area was cutting down shrub vegetation in study site 34 Appendix 1: Distribution of mature trees layer bases on the height Hvn Frequency BA1 BA2 HHT1 HHT2 5 12 18 10 11 14 26 10 10 18 11 10 18 12 13 12 13 0 14 More 0 0 Total 46 51 49 86 Appendix 2: Distribution of mature tree layer bases on diameter D1.3 Frequency BA1 BA2 HHT1 HHT2 10 17 15 11 27 20 22 16 17 34 25 16 12 15 30 35 0 More 1 Total 46 51 49 86 35 Appendix 3: Tree data collection Plot BA1 No.1 Name D1.3(cm) Hvn(m) Hunder(m) Crown D.(m) Castanopsis boisii 25.6 10.5 5.2 5.1 Castanopsis boisii 22.6 9.8 5.3 5.3 Castanopsis boisii 22.0 9.9 5.5 4.9 Castanopsis boisii 18.7 8.7 4.6 5.1 Castanopsis boisii 22.7 10.7 5.4 Castanopsis boisii 18.3 8.5 4.4 4.8 Castanopsis boisii 13.6 7.8 4.1 4.1 Castanopsis boisii 17.4 8.3 4.5 4.2 Castanopsis boisii 18.4 9.7 5.2 10 Castanopsis boisii 18.4 9.2 4.8 5.2 11 Castanopsis boisii 22.5 10.2 4.9 5.6 12 Castanopsis boisii 18.6 4.3 4.5 13 Castanopsis boisii 16.0 8.6 4.5 4.3 14 Castanopsis boisii 14.0 7.9 4.2 15 Castanopsis boisii 16.5 8.2 4.1 4.4 16 Castanopsis boisii 20.0 9.5 4.7 4.6 17 Castanopsis boisii 9.0 6.3 3.8 3.9 18 Castanopsis boisii 16.1 8.4 4.5 4.3 19 Castanopsis boisii 24.0 10.4 5.2 5.1 20 Castanopsis boisii 22.9 11.4 5.8 5.3 21 Castanopsis boisii 17.3 13.8 6.2 5.4 22 Castanopsis boisii 7.2 5.8 3.6 4.1 36 23 Castanopsis boisii 15.9 7.6 3.8 4.2 24 Castanopsis boisii 22.7 10.4 5.1 4.8 25 Castanopsis boisii 21.0 12.5 6.8 5.8 26 Castanopsis boisii 29.3 13.7 6.9 5.7 27 Castanopsis boisii 17.8 9.6 4.7 4.5 28 Castanopsis boisii 19.2 9.8 4.9 4.6 29 Castanopsis boisii 21.9 8.6 4.4 4.5 30 Castanopsis boisii 15.0 6.9 3.5 4.1 31 Castanopsis boisii 19.8 9.7 4.8 4.5 32 Castanopsis boisii 18.9 8.5 4.2 4.4 33 Castanopsis boisii 23.9 9.9 5.1 5.2 34 Castanopsis boisii 19.4 10.4 5.3 4.8 35 Castanopsis boisii 21.6 10.6 5.6 5.4 36 Castanopsis boisii 23.4 11.4 5.9 4.6 37 Castanopsis boisii 20.3 10.9 5.7 5.3 38 Castanopsis boisii 22.4 11.6 5.4 39 Castanopsis boisii 19.3 10.4 5.2 5.4 40 Castanopsis boisii 19.4 10.7 5.7 5.1 41 Castanopsis boisii 38.3 13.2 6.5 4.8 42 Castanopsis boisii 19.8 10.7 5.7 5.6 43 Castanopsis boisii 22.0 10.5 5.4 5.2 44 Castanopsis boisii 16.7 8.9 4.8 4.3 45 Castanopsis boisii 18.6 10.2 4.9 4.5 46 Castanopsis boisii 21.6 11.4 5.2 4.8 37 Plot BA2 No.1 Name D1.3(cm) Hvn(m) Hunder(m) Crown D.(m) Castanopsis boisii 21.1 10.5 4.7 4.5 Castanopsis boisii 7.7 5.7 2.8 3 Castanopsis boisii 6.0 5.2 2.9 Castanopsis boisii 15.6 8.8 3.5 Castanopsis boisii 13.6 7.8 3.7 3.5 Castanopsis boisii 14.6 7.9 3.4 3.3 Castanopsis boisii 15.4 8.9 4.5 4.2 Castanopsis boisii 14.7 8.4 3.9 3.8 Castanopsis boisii 15.6 8.7 4.3 4.5 10 Castanopsis boisii 6.4 7.2 3.4 11 Castanopsis boisii 8.6 6.7 3.1 3.2 12 Castanopsis boisii 8.6 6.2 3 13 Castanopsis boisii 10.0 7.4 3.3 3.5 14 Castanopsis boisii 12.0 7.9 3.5 3.4 15 Castanopsis boisii 10.2 7.2 3 16 Castanopsis boisii 8.2 6.8 3.3 3.1 17 Castanopsis boisii 9.2 7.7 3.5 18 Castanopsis boisii 7.0 5.6 3 19 Castanopsis boisii 15.3 8.4 4.2 3.7 20 Castanopsis boisii 14.9 8.2 3.9 21 Castanopsis boisii 6.2 6.1 3.6 22 Castanopsis boisii 14.8 7.5 3.4 3.2 23 Castanopsis boisii 6.9 6.6 3.2 3.3 24 Castanopsis boisii 16.1 8.5 4.5 4.2 25 Castanopsis boisii 17.0 4.4 4.5 38 26 Castanopsis boisii 18.8 9.7 4.7 4.8 27 Castanopsis boisii 8.4 6.8 3.4 3.2 28 Castanopsis boisii 12.4 7.9 3.8 3.5 29 Castanopsis boisii 8.3 7.6 3.6 3.4 30 Castanopsis boisii 16.0 9.5 4.6 4.4 31 Castanopsis boisii 14.6 7.4 3.5 3.4 32 Castanopsis boisii 7.9 6.1 3.1 33 Castanopsis boisii 15.2 8.6 3.9 3.8 34 Castanopsis boisii 14.5 8.3 3.4 4.3 35 Castanopsis boisii 20.5 10.4 4.9 4.8 36 Castanopsis boisii 16.7 9.8 5.2 4.6 37 Castanopsis boisii 6.0 5.8 2.8 38 Castanopsis boisii 23.9 11.4 5.1 4.8 39 Castanopsis boisii 6.9 5.4 3 40 Castanopsis boisii 18.6 9.6 4.6 4.5 41 Castanopsis boisii 21.5 10.4 4.7 4.9 42 Castanopsis boisii 11.1 7.2 3.2 43 Castanopsis boisii 20.3 10.6 4.3 4.4 44 Castanopsis boisii 8.8 3.8 3.4 45 Castanopsis boisii 24.5 11.4 5.4 46 Castanopsis boisii 19.4 9.8 4.8 4.2 47 Castanopsis boisii 15.2 8.9 4.5 4.3 48 Castanopsis boisii 20.0 10.2 4.6 4.1 49 Castanopsis boisii 18.5 9.5 4.4 4.7 50 Castanopsis boisii 16.5 9.2 4.5 51 Castanopsis boisii 22.4 11.2 4.3 39 Plot HHT1 No.1 Name D1.3(cm) Hvn(m) Hunder(m) Crown D.(m) Castanopsis boisii 16.2 9.2 4.5 3.8 Castanopsis boisii 17.0 8.5 3.9 3.6 Castanopsis boisii 9.4 3.5 3.1 Castanopsis boisii 28.8 10.1 4.6 5.2 Castanopsis boisii 18.0 4.1 4.1 Castanopsis boisii 19.2 9.7 4.8 4.5 Castanopsis boisii 9.3 6.5 3.2 Castanopsis boisii 16.9 7.4 3.5 3.1 Castanopsis boisii 9.0 6.8 3.4 3.2 10 Castanopsis boisii 18.9 8.2 3.5 11 Castanopsis boisii 16.7 8.4 3.9 3.7 12 Castanopsis boisii 20.2 11 5.2 5.4 13 Castanopsis boisii 23.5 10.4 5.1 14 Castanopsis boisii 8.5 6.4 4.1 3.3 15 Castanopsis boisii 22.5 11.8 6.1 5.5 16 Castanopsis boisii 12.2 7.8 4.2 3.6 17 Castanopsis boisii 11.1 7.9 4.5 3.3 18 Castanopsis boisii 34.5 13.5 6.4 19 Castanopsis boisii 14.4 8.8 4.8 3.8 20 Castanopsis boisii 17.7 9.6 5.2 4.2 21 Castanopsis boisii 19.8 11.4 5.9 5.8 22 Castanopsis boisii 17.1 9.7 4.7 4.6 23 Castanopsis boisii 17.8 7.3 3.9 3.9 24 Castanopsis boisii 19.9 8.3 4.1 40 25 Castanopsis boisii 34.8 13.7 6.6 5.8 26 Castanopsis boisii 26.2 10.6 5.2 5.1 27 Castanopsis boisii 21.5 8.5 4.3 4.2 28 Castanopsis boisii 12.4 5.8 3.1 3.3 29 Castanopsis boisii 19.1 7.5 3.7 3.4 30 Castanopsis boisii 23.1 9.1 4.4 4.8 31 Castanopsis boisii 21.2 9.1 4.5 4.9 32 Castanopsis boisii 12.7 8.2 4.1 4.1 33 Castanopsis boisii 38.2 14.0 7.2 6.5 34 Castanopsis boisii 22.6 10.7 5.2 5.7 35 Castanopsis boisii 21.6 9.5 5.2 36 Castanopsis boisii 28.0 11.8 6.3 5.9 37 Castanopsis boisii 15.5 8.9 4.7 4.8 38 Castanopsis boisii 15.1 8.5 4.5 4.5 39 Castanopsis boisii 25.2 9.3 4.8 4.3 40 Castanopsis boisii 21.6 8.8 4.4 4.1 41 Castanopsis boisii 24.2 9.3 4.1 4.6 42 Castanopsis boisii 30.3 13.5 6.8 5.8 43 Castanopsis boisii 17.1 9.8 5.1 4.7 44 Castanopsis boisii 16.1 8.4 4.6 4.3 45 Castanopsis boisii 9.9 6.8 3.2 3.5 46 Castanopsis boisii 24.9 8.3 4.2 3.8 47 Castanopsis boisii 20.2 8.9 4.8 4.1 48 Castanopsis boisii 28.2 10.4 5.1 5.5 49 Castanopsis boisii 10.2 7.2 3.5 3.1 41 Plot HHT2 No.1 Name D1.3(cm) Hvn(m) Hunder(m) Crown D.(m) Castanopsis boisii 26.0 9.4 4.3 4.7 Castanopsis boisii 13.0 8.6 4.2 4.5 Castanopsis boisii 23.5 10.5 4.8 4.3 Castanopsis boisii 22.5 9.8 4.7 4.7 Castanopsis boisii 20.4 8.9 4.5 Castanopsis boisii 13.7 7.9 3.9 4.2 Castanopsis boisii 26.5 11.4 5.5 5.8 Castanopsis boisii 25.3 10.5 5.3 5.3 Castanopsis boisii 27.8 11.7 5.7 5.6 10 Castanopsis boisii 29.2 12.4 5.9 5.7 11 Castanopsis boisii 11.4 7.2 3.2 4.2 12 Castanopsis boisii 9.0 6.8 3.1 13 Castanopsis boisii 12.1 8.1 3.7 4.3 14 Castanopsis boisii 13.4 7.6 3.7 4.5 15 Castanopsis boisii 16.8 8.7 4.2 4.4 16 Castanopsis boisii 17.4 8.4 4.1 4.3 17 Castanopsis boisii 12.0 7.9 3.9 4.2 18 Castanopsis boisii 13.7 8.1 4.6 19 Castanopsis boisii 14.2 7.7 3.8 4.2 20 Castanopsis boisii 15.6 8.7 4.5 4.1 21 Castanopsis boisii 13.0 4.3 22 Castanopsis boisii 24.5 10.8 4.7 5.2 23 Castanopsis boisii 18.5 8.6 4.5 4.2 42 24 Castanopsis boisii 21.2 9.9 4.9 4.5 25 Castanopsis boisii 15.1 7.9 3.8 4.3 26 Castanopsis boisii 13.4 8.4 4.2 4.5 27 Castanopsis boisii 20.3 10.2 4.7 5.3 28 Castanopsis boisii 14.0 9.7 4.5 4.4 29 Castanopsis boisii 14.2 7.9 3.6 3.9 30 Castanopsis boisii 12.2 6.8 3.2 3.6 31 Castanopsis boisii 20.8 11 5.1 4.9 32 Castanopsis boisii 15.0 8.3 4.2 4.2 33 Castanopsis boisii 23.0 8.8 4.4 3.7 34 Castanopsis boisii 19.5 9.2 4.7 4.5 35 Castanopsis boisii 19.8 9.4 4.5 4.4 36 Castanopsis boisii 16.8 8.5 4.2 4.3 37 Castanopsis boisii 23.3 10.5 5.1 4.7 38 Castanopsis boisii 16.4 8.8 4.3 4.5 39 Castanopsis boisii 17.8 10.6 5.2 5.3 40 Castanopsis boisii 16.3 9.5 5.2 41 Castanopsis boisii 22.3 10.2 4.9 42 Castanopsis boisii 14.6 7.8 3.8 4.4 43 Castanopsis boisii 15.7 8.3 4 44 Castanopsis boisii 18.7 9.8 5.3 5.2 45 Castanopsis boisii 14.8 3.6 4.5 46 Castanopsis boisii 13.0 7.6 3.5 4.2 47 Castanopsis boisii 19.0 9.5 4.2 4.3 48 Castanopsis boisii 27.9 11.6 5.2 5.4 43 49 Castanopsis boisii 19.2 9.6 4.6 4.6 50 Castanopsis boisii 16.5 8.2 4.1 4.3 51 Castanopsis boisii 17.3 9.4 4.8 4.7 52 Castanopsis boisii 11.8 6.5 3.3 53 Castanopsis boisii 13.4 8.9 4.5 4.3 54 Castanopsis boisii 15.6 8.4 4.2 4.1 55 Castanopsis boisii 13.0 7.2 3.7 4.3 56 Castanopsis boisii 16.5 9.6 4.5 4.5 57 Castanopsis boisii 16.0 9.1 4.2 4.3 58 Castanopsis boisii 16.3 8.7 4.1 4.7 59 Castanopsis boisii 20.2 10.8 5.2 60 Castanopsis boisii 14.7 7.8 3.8 4.3 61 Castanopsis boisii 17.3 9.5 4.6 4.5 62 Castanopsis boisii 16.3 8.2 4.2 63 Castanopsis boisii 22.5 10.3 4.7 5.6 64 Castanopsis boisii 15.5 8.3 4.1 4.2 65 Castanopsis boisii 17.3 8.9 4.3 4.1 66 Castanopsis boisii 27.3 11.4 5.4 4.6 67 Castanopsis boisii 16.5 8.7 4.5 4.4 68 Castanopsis boisii 18.9 9.2 4.2 4.3 69 Castanopsis boisii 14.6 7.8 3.8 4.1 70 Castanopsis boisii 14.3 7.4 4.2 71 Castanopsis boisii 22.0 10.5 5.2 5.3 72 Castanopsis boisii 19.8 9.2 4.5 4.6 73 Castanopsis boisii 15.1 6.8 3.3 4.1 44 74 Castanopsis boisii 14.0 7.8 3.4 3.8 75 Castanopsis boisii 18.8 9.4 4.6 4.8 76 Castanopsis boisii 27.2 11.2 4.9 4.7 77 Castanopsis boisii 13.2 7.6 3.3 4.2 78 Castanopsis boisii 19.4 8.6 4.5 4.9 79 Castanopsis boisii 18.8 8.3 4.3 4.1 80 Castanopsis boisii 24.4 10.9 5.3 81 Castanopsis boisii 23.5 9.4 4.6 4.8 82 Castanopsis boisii 16.8 8.8 4.5 4.9 83 Castanopsis boisii 15.0 8.2 4.1 4.3 84 Castanopsis boisii 14.4 6.9 3.2 4.3 85 Castanopsis boisii 26.2 11.3 5.1 5.4 86 Castanopsis boisii 15.8 7.9 3.6 4.2 45 Appendix 4: Descriptive Statistic of mature trees in study site Plot BA1 D1.3 Hvn Mean 19.7826087 Mean 9.797826 Standard Error 0.711033162 Standard Error 0.253792 Median 19.4 Mode 22 Median 9.85 Mode 10.4 Standard Deviation 4.822461536 Standard Deviation 1.721303 Sample Variance 23.25613527 Sample Variance 2.962884 Kurtosis 4.808832772 Kurtosis 0.453084 Skewness 0.771274032 Skewness 0.133674 Range 31.1 Range Minimum 7.2 Minimum 5.8 Maximum 38.3 Maximum 13.8 Sum 910 Sum 450.7 Count 46 Count 46 Plot BA2 D1.3 Mean Standard Error Median Mode Hvn 13.77647059 0.7315768 14.7 Mean 8.207843 Standard Error 0.230002 Median 8.2 Mode 7.9 Standard Deviation 5.224503354 Standard Deviation 1.64254 Sample Variance 27.29543529 Sample Variance 2.697937 Kurtosis -0.997711104 Kurtosis -0.75752 Skewness 0.140253165 Skewness 0.112558 Range 18.5 Range 6.2 Minimum Minimum 5.2 Maximum 24.5 Maximum 11.4 Sum 702.6 Sum 418.6 Count 51 Count 51 46 Plot HHT1 D1.3 Hvn Mean 19.56122449 Mean 9.210204082 Standard Error 0.991982384 Standard Error 0.275305101 Median 19.1 Median 8.9 Mode 20.2 Mode 8.5 Standard Deviation 6.943876689 Standard Deviation 1.927135709 Sample Variance 48.21742347 Sample Variance 3.713852041 Kurtosis 0.264190885 Kurtosis 0.484224594 Skewness 0.582326229 Skewness 0.795966821 Range 29.7 Range 8.2 Minimum 8.5 Minimum 5.8 Maximum 38.2 Maximum 14 Sum 958.5 Sum 451.3 Count 49 Count 49 Plot HHT2 D1.3 Hvn Mean 17.90697674 Mean 8.983721 Standard Error 0.493735837 Standard Error 0.141255 Median Mode 16.65 13 Median 8.75 Mode 9.4 Standard Deviation 4.578717794 Standard Deviation 1.309949 Sample Variance 20.96465663 Sample Variance 1.715967 Kurtosis -0.317920477 Kurtosis -0.39069 Skewness 0.679970693 Skewness 0.445379 Range 20.2 Range 5.9 Minimum Minimum 6.5 Maximum 29.2 Maximum 12.4 Sum 1540 Sum 772.6 Count 86 Count 86 47 ... to early April, Hai Duong has more rain due to the transition from dry season to rainy season Rainy season lasts from April to October In Hai Duong, the annual average rainfall is from 1,300 to. .. boisii in Hai Duong province for sustainable forest development 2.1.2 Specific objectives  Determining the characteristic of stands of Castanopsis boisii Hickel et A Camus  Purposing some solutions. .. Linh commune has the largest area of Castanopsis boisii forest with more than 2000 which is mainly concentrated in Bac An and Hoang Hoa Tham communes Forest rehabilitation in Vietnam in general,