Biomass and carbon accumulation in rhizophora stylosa griff forest at hoang tan commune quang yen town quang ninh province

ACKNOWLEDGEMENT Firstly, i would like to express my sincere graititude to my advisor Dr Pham Minh Toai for the continuous supports of my thesis and related research; for his patience, motivation and immense knowledge His guidance helped me in all the time of research and writing of this thesis I could not have imagined having a better advisor and mentor for my thesis My sincere thanks also go to Prof.Dr Lee MacDonald who always supported me, read all email and ried to help as much as possible with all of their enthusiasm I also decicate my grateful for all the Doctors, Master and Lectures in VNUF, who gave me a lot of knowledge, favors as well as memories I would like to thank Dr Nguyen Thanh Tien, Lecturer of Thai Nguyen University of Agricultural and Forestry for help me with valuable documents useful for my thesis Another thank is for all the people in Center for Science and Agricultural and Forestry Production in Quang Ninh who helped me during my researching process Last but not least, I would like to thank to my family: my parents and my sister and brother for theirsupporting me spiritually throughout writing this thesis and my life in general ABSTRACT Quang Yen district has 2,671 mangroves, compared to other regions in the province, the area of forest here is not abundant, but in Quang Yen forest area is a very important position in the protection dyke, discovered development of agricultural production, aquaculture protection This research concentratios on three objectives: Identify some biomass and carbon accumulation characteristics and of R stylosa Griff forest at the study area; Determine the relationship between biomass and carbon accumulation in R stylosa Griff mangrove forests; Propose rapid methods for biomass identification of the studied forest To deal with objectives as above mentioned, the research established 30 temporary plots of of 100m2 (10mx10m) each in R stylosa Griff forest The studied results show that average 3.6 cm diameter trees about 0.6 kilograms of carbon accumulated in tree biomass Total biomass and carbon accumulation sharp fluctuations between tree density, diameter, height The total biomass of the populations average of 0.011 tons/ha, the amount of carbon in forest biomass accumulation averaged 1.03 tons C/ha However, to calculate with greater accuracy (tighter correlation) we should use correlation equation Y = a + b * X, specific: Y = 0.693 X + 0.347 and Y = 0.833 X + 0.347 with r2= 0.193 In conclusion, the proportion of biomass and carbon accumulation in the individual parts of the plant as well as the majority populations in the body parts and through the process of analysis and correlation functions, we can easily calculate the dry biomass, cumulative carbon content of mangrove species in correlation equation LIST OF ABBRIVIATION AGB: above ground biomass C: Carbon CO2: Carbon Dioxide TAGB: The total biomass of population (ton/ha) Wt: The total biomass of tree Wsk: dry biomass of stem ( kg, ton/ha) WBrk: dry biomass of branch ( kg, ton/ha) Wrk: dry biomass of root ( kg, ton/ha) Wlk: dry biomass of leaves ( kg, ton/ha) Wst: fresh biomass of stem ( kg, ton/ha) WBrt: fresh biomass of branch ( kg, ton/ha) Wrt: fresh biomass of root ( kg, ton/ha) Wlt: fresh biomass of leaves ( kg, ton/ha) TABLE OF CONTENTS ACKNOWLEDGEMENT ABSTRACT LIST OF ABBRIVIATION TABLE OF CONTENTS LIST OF TABLES LIST OF FIGURES Chapter INTRODUCTION Chapter NATURAL CONDITIONS OF STUDY AREA 2.1 Geographic and topography conditions 2.2 Climate characteristics: 2.3 Land and Water resoureces Chapter STUDY OBJECTIVES AND METHODS 3.1 Study objectives 3.2 Method 3.2.1 Data sources 3.2.2 Data collection method 3.2.3 Data analysis method 10 Chapter RESULTS AND DISCUSSIONS 13 4.1 Biomass characteristics of individual tree and populations 13 4.1.1 Structure of fresh biomass of individual trees 13 4.1.2 Structure of dry biomass of individual trees 14 4.1.3 Structure of the populations biomass 15 4.2 Amount of carbon accumulation in different parts of individual trees and populations 19 4.2.1 Carbon accumulation in the individual parts of plants 19 4.2.2 The ability to accumulate carbon in the population 22 4.3 Correlation models between biomass and carbon accumulation capacity 25 4.3.1 Estimation model of the total dry biomass of individual trees 25 4.3.2 Model estimates of carbon stocks individual tree 27 4.4 Propose solutions for quickly biomass identification 28 Chapter CONCLUSIONS AND RECOMMENDATIONS 29 5.1 Conclusion 29 5.2 Recomemendation 29 Chapter REFFERENCES 30 APPENDIX LIST OF TABLES Table 4.1 Structure of dry biomass populations 16 Table 4.2 The ability to accumulate carbon in the individual parts of plants 20 Table 4.3 Cumulative carbon populations 23 Table 4.4 Model estimates the total dry biomass of individual trees 26 Table 4.5 Model estimates of carbon stocks estimate individual tree 27 LIST OF FIGURES Figure 2.1 The map of Quang Yen town, Quang Ninh province Figure 3.1 Plot establishment Figure 4.1 The propotion of fresh biomass in different parts of R Stylosa Griff 14 Figure 4.2 The proportion of dry biomass in different parts of R stylosa Griff 14 Figure 4.3 The proportion of dry biomass parts of R Stylosa Griff population 18 Figure 4.4 The proportion of accumulation of carbon stocks in individual trees 22 Figure 4.5 The proportion of average carbon accumulation in parts populations 25 Figure 4.6 The diagram describes the correlation between dry biomass and survey factors D1.3 26 Figure 4.7 The diagram describes the correlation between carbon stocks and factors investigated DBH 27 Appendix A Appendix B Chapter INTRODUCTION Mangroves are an unique ecosystem in estuaries, coastal tropic, with diverse biological resources and sensitive to the environmental change It has strong effect in keeping sediment, limiting erosion, accretion fixed, against the waves, providing nutrients for aquatic species, acts as a biofilter, maintain balance ecology in the coastal areas Studies on biomass and carbon in forest ecosystems has been conducted from early of the 19th century in order to determine carbon cycle - an important factor in the nutrition management and forest productivity Recent studies of biomass and carbon absorption capacity of the forest becomes more important in the context of climate change Currently, climate change is a serious threat to the vital interests of many countries around the world People are facing with negative effects such as disease, poverty, loss of shelter, lack of cultivated land, the decline of biodiversity, etc.Climate change is a natural phenomenon that occurs throughout the history of Earth However, the increasing in CO2 emissions in the atmosphere recently has made the Earth's climate changed There are many evidences that indicate that humans have caused greenhouse gases (CO2, CH4), which affect to global climate change With forest heron increasingly shrunk the logging process is not reasonable cause to carbon accumulation and more According to Christopher Field (2007) :"The amount of carbon stored in forest ecosystems attractive to increasing atmospheric CO2 and global warming process happen faster,"( Cited from Le Tan Loi) [1] and in accordance with the organization's statement Statistics Antarctica (BAS) in 2006 There are nearly 10 billion tons of CO2 in the atmosphere, up 35% compared to 1990 One of the solutions to mitigate and adapt to the effects of climate change, strengthen management of forest resources and the environment, mitigation of greenhouse gas emissions for developing country participation in the program is the REDD (Reducing Emission and forest Degradation Deforestation: reducing greenhouse gas emissions from deforestation and failure deforestation), REDD + (REDD later stage, the developing countries reduce forest loss and degradation to receive financial support from developed countries) including Vietnam The overall objective of Vietnam participating REDD + is to contribute to reduce greenhouse gas emissions, increase the volume of forest carbon, conserve biodiversity, and contribute to poverty reduction, environmental protection and promote sustainable development in Vietnam Carbon in tree biomass comes from carbon dioxide gas (CO2) in the atmosphere through the process of plant growth The loss of vegetation cover, burning or decomposing wood will make the carbon back to the atmosphere as CO2, or sometimes as methane (CH4) if plants decompose Thus, the forest is the sink that contains absorbed carbon in the air, although there are several cycling gases basically occur daily "Mangroves are ratio as capable of achievement higher accumulation of carbon on the surface of other forest land (Ong, 1995) and created the role of these reservoirs of carbon in the ecosystem coast (Kristensen, 2007) ( Cited from Vien Ngoc Nam) [2] "Mangroves accumulate and store carbon from the process of photosynthesis, carbon mostly is stored in the form of increased accumulation of biomass of plant parts in the forest and forest land However, parallel to the process of accumulation is the process of liberating carbon from the ecosystem due to respiration, decomposition by microorganisms If the carbon accumulation is larger than the emission process, the forest is considered the role of reducing CO2 in the atmosphere and mangrove planting project under the Clean Development Mechanism (CDM) will implement effective and feasible The study of biomass and productivity of mangroves have also havebeen interested in many countries since 1978 (Phan Nguyen Hong, 1991) (Cited from Vien Ngoc Nam) [2] Around the world, about research on biomass: There have been many authors such as Clough, BF and Scott, K, (1989); Clough, BF, (1998); Clough, BF, Dixon, P and Dalhaus, O , (1997) studied biomass on a large scale or on a national scope "In Australia there have been many studies related to mangrove biomass as correlation studies to assess regression above ground biomass of mangrove trees (Cited from Phan Nguyen Hong) [2] Research on natural mangrove and plantation mangroves biomass, Christen, B (1978) Ong, J E et al (1983) ( Cited from Vien Ngoc Nam) [2] Research on wild mangrove forest and mangrove plantation biomass (Rhizophora apiculata) Most of the authors are researchers on the ground biomass, particularly Akira, K et al (1987.2000) have studied the size and root biomass under the ground "About accumulating carbon: Center for International Forestry of the Research (CIFOR) shows carbon sinks of mangrove ecosystems in the Indian-Pacific is higher twice than the rainforests and temperateratio Research by Ha et al (2001) showed that carbon accumulation in the soil of the forest in Thailand ranged from 19.5 to 1158.1 tons/ The study also provides hypotheses about the factors affecting soil carbon accumulation of the mangrove cover flooding, age and species composition of forests Murdiyarso et al (2010) studied the ecosystem carbon storage in mangrove conservation area of Tanjung Puting, Segara Anakan and Bunaken, Indonesia, carbon storage results ranged from 437 tons/ha to 2,186 tons/ In particular, carbon underground (including soil carbon and carbon root) account for 72% - 99% Adame et al (2013) ,mangroves have the highest carbon stocks 987 tons/ha, followed by mangroves average 623 tons/ha, low mangroves 381 tons/ha and swamps 177 tons/ha In fact, the studies did by scientists are mostly quantitative carbon on the ground biomass and overall for the whole forest stand, forest type, whereas there are lack of specific research for each species in the mangrove, different locations have different characteristic species ( Cited from Vien Ngoc Nam) In Vietnam, the study of biomass and carbon accumulation had some case studies following notable About biomass: Phan Nguyen Hong and Nguyen Hoang Tri (1984) ( Cited from Nguyen Thi Kim Cuc) [ 8] evaluated the plant biomass and primary productivity in Ca Mau mangrove forest Phan Nguyen Hong (1991) ( Cited from Nguyen Thi Kim Cuc) [8], have studied terrestrial biomass of mangrove forests in the total 10-year-old lands were Chapter CONCLUSIONS AND RECOMMENDATIONS 5.1 Conclusion The ratio of biomass and carbon accumulation in the individual parts of the plant as well as the majority populations in the body parts Average 3.6 cm diameter trees about 0.6 kilograms of carbon accumulated in tree biomass Total biomass and carbon accumulation sharp fluctuations between tree density, diameter, height The total biomass of the populations average of 0.011 tons / ha, the amount of carbon in forest biomass accumulation averaged 1.03 tons C / Through the process of analysis and correlation functions, we can easily estimate based either on equation: Y = 0.693X + 0.347 or equation Y = 0.833 X + 0.347 5.2 Recomemendation - The thesis has study biomass and carbon stocks on the ground of planting 1987, have not done at differents ages to have an overview over - The study of the relationship of biomass, carbon stocks and other growth indicators not mentioned outside the parameter (DBH and Ht) - Results identifiable only recommended for initial reference should have the research and subsequent testing conducted for different ages - Conduct research in soil carbon stocks to work determining the amount of carbon absorbed in mangrove plantations are fuller - Conduct research in soil carbon stocks to work determining the amount of carbon absorbed in mangrove plantations are fuller 29 Chapter REFFERENCES Lê Tấn Lợi (2015) “Phương pháp nghiên cứu tích lũy carbon hệ sinh thái rừng ngập mặn theo CIFOR, Trường Đại học Cần Thơ” Viên Ngọc Nam(2004) ”Nghiên cứu sinh khối suất sơ cấp quần thể mắm trắng (Avicennia alba BL) tự nhiên Cần Giờ, thành phố Hồ Chí Minh,Viện Khoa học Lâm Nghiệp Việt Nam, Hà Nội.” Trinh Xuan Thanh, Do Huu Thu ( 2012) “Nghiên cứu khả hấp thụ CO2 rừng trồng keo tai tượng xã Ngọc Thanh, thị xã Phúc Yên, tỉnh Vĩnh Phúc.” Komiyama,A.,Ong,J.E Poungparn ,S.(2008),”Allometry, biomass, and productivity of mangroves forests:A review, Aquatic Botany” Nguyen Hoang Tri (2006).’Khôi phục bảo tồn hệ sinh thái rừng ngập mặn chế phát triển sạch., Nhà xuất Nông nghiệp” Nguyễn Thanh Tiến (2012) “Nghiên cứu khả hấp thụ CO2 trạng thái rừng thứ sinh phục hồi tự nhiên sau khai thác kiệt tỉnh Thái Nguyên,Luận án tiến sĩ nông nghiệp,Trường Đại học Thái Nguyên” Nguyễn Thị Kim Cúc, Phan Nguyên Hồng,Hoàng Thị Sản (2015).”Tuyển tập hội thảo khoa học quốc gia: Phục hồi quản lý hệ sinh thái rừng ngập mặn bối cảnh biến đổi khí hậu lần thứ 2,Ban nghiên cứu hệ sinh thái rừng ngập mặn,đại học Quốc gia Hà Nội.” Nguyễn Thanh Tiến (2008) ”Bài giảng Phân loại &Điều tra rừng, Đại học Nông Lâm Thái Nguyên” Viên Ngọc Nam(1996).”Nghiên cứu sinh khối suất sơ cấp rừung Đước trồng Cần Giờ Thành phố Hồ Chí Minh, Sở NN & PTNT Hồ Chí Minh.” 30 APPENDIX Appendix 01 The mean growth parameters of trees in studied sample plots No Plot D1.3(cm) Ht(m) Density(N/ha) 1 3.05 100 2 3.12 2.2 200 3 2.77 1.5 100 4 3.25 2.3 500 5 2.72 1.1 300 6 3.24 2.4 2000 7 3.3 2.3 500 8 3.35 2.2 100 9 3.51 2.4 1000 10 10 3.74 2.2 200 11 11 3.71 2.3 1500 12 12 3.6 2.5 2200 13 13 3.55 2.4 1900 14 14 3.52 2.5 3600 15 15 3.61 2.7 3800 16 16 3.63 2.6 3900 17 17 3.45 2.5 1300 18 18 4.05 2.8 3200 19 19 4.25 2.1 2600 20 20 4.11 2.9 2900 21 21 3.94 2.6 800 22 22 3.86 2.7 3700 23 23 4.25 2.8 2500 24 24 4.32 2.6 2400 25 25 3.41 2.4 3700 26 26 3.78 2.5 3700 27 27 3.05 2.8 900 28 28 3.32 2.1 200 29 29 4.25 2.6 300 30 30 4.15 2.4 500 31 Note Appendix 02 Fresh biomass of Rhizophora stylosa Griff Species No DBH(cm) Ht(m) 3.05 Wst Wbrt Wlt Wrt Wtt kg % kg % kg % kg % kg 1.6 72.7 0.4 18.2 0.1 4.5 0.1 4.6 2.2 3.12 2.2 1.6 69.6 0.4 17.4 0.2 8.7 0.1 4.3 2.3 2.77 1.5 0.3 21.4 0.8 57.1 0.1 7.1 0.2 14.3 1.4 3.25 2.3 1.9 73.1 0.3 11.5 0.3 11.5 0.1 3.8 2.6 2.72 1.1 0.4 44.4 0.2 22.2 0.2 22.2 0.1 11.1 0.9 3.24 2.4 1.7 73.9 0.1 4.3 0.1 4.3 0.4 17.4 2.3 3.3 2.3 1.6 64 0.1 0.4 16 0.4 16 2.5 3.35 2.2 1.9 70.4 0.6 22.2 0.1 3.7 0.1 3.7 2.7 3.51 2.4 0.9 33.3 1.5 55.6 0.2 7.4 0.1 3.7 2.7 10 3.74 2.2 0.2 9.5 1.3 61.9 0.3 14.3 0.3 14.3 2.1 11 3.71 2.3 1.5 62.5 0.7 29.2 0.1 4.2 0.1 4.2 2.4 12 3.6 2.5 1.7 60.7 0.4 14.3 0.4 14.3 0.3 10.7 2.8 13 3.55 2.4 1.9 70.4 0.2 7.4 0.3 11.1 0.3 11.1 2.7 14 3.52 2.5 0.8 36.4 0.3 13.6 0.6 27.3 0.5 36.4 2.2 15 3.61 2.7 1.8 62.1 0.1 3.4 0.7 24.1 0.3 10.3 2.9 16 3.63 2.6 1.2 52.2 0.4 17.4 0.3 13 0.4 17.4 2.3 17 3.45 2.5 1.6 59.3 0.6 22.2 0.1 3.7 0.4 14.8 2.7 18 4.05 2.8 2.1 70 0.6 20 0.1 3.3 0.2 6.7 32 19 4.25 2.1 1.6 72.7 0.2 9.1 0.2 9.1 0.2 9.1 2.2 20 4.11 2.9 62.5 0.7 21.9 0.4 12.5 0.1 3.1 3.2 21 3.94 2.6 1.7 58.6 0.5 17.2 0.4 13.8 0.3 10.3 2.9 22 3.86 2.7 2.2 71 0.4 12.9 0.1 3.2 0.4 12.9 3.1 23 4.25 2.8 60.6 30.3 0.1 0.3 9.1 3.3 24 4.32 2.6 1.4 56 0.8 32 0.1 0.2 2.5 25 3.41 2.4 0.7 25.9 37 0.6 22.2 0.4 14.8 2.7 26 3.78 2.5 1.3 54.2 0.6 25 0.4 16.7 0.1 4.2 2.4 27 3.05 2.8 1.8 58.1 0.4 12.9 0.7 22.6 0.2 6.5 3.1 28 3.32 2.1 0.8 40 0.9 45 0.2 10 0.1 29 4.25 2.6 1.1 44 0.9 36 0.2 0.3 12 2.5 30 4.15 2.4 1.2 52.2 0.8 34.8 0.3 13 0.1 4.3 2.3 Average 3.60 2.38 1.42 55.10 0.57 23.60 0.28 11.10 0.24 10.20 2.50 33 Appendix 03: Dry biomass of Rhizophora stylosaGriff species No DBH(cm) Ht(m) 3.05 Wsk Wbrk Wlk Wrk Wtk kg % kg % kg % kg % kg 0.95 73.08 0.25 0.19 0.05 3.85 0.05 3.85 1.3 3.12 2.2 0.6 70.59 0.14 16.47 0.07 8.24 0.04 4.71 0.85 2.77 1.5 0.21 21 0.58 58 0.07 0.14 14 3.25 2.3 1.12 73.2 0.17 11.11 0.18 11.76 0.06 3.92 1.53 2.72 1.1 0.22 44 0.12 24 0.11 22 0.05 10 0.5 3.24 2.4 0.67 74.44 0.03 3.33 0.04 4.44 0.16 17.78 0.9 3.3 2.3 0.89 63.57 0.07 0.22 15.71 0.22 15.71 1.4 3.35 2.2 0.76 70.37 0.24 22.22 0.04 3.7 0.04 3.7 1.08 3.51 2.4 0.35 33.02 0.59 55.66 0.08 7.55 0.04 3.77 1.06 10 3.74 2.2 0.12 9.38 0.8 62.5 0.18 14.06 0.18 14.06 1.28 11 3.71 2.3 0.55 61.11 0.27 30 0.04 4.44 0.04 4.44 0.9 12 3.6 2.5 0.74 61.67 0.15 12.5 0.17 14.17 0.14 11.67 1.2 13 3.55 2.4 0.75 70.75 0.07 6.6 0.12 11.32 0.12 11.32 1.06 14 3.52 2.5 0.46 35.94 0.17 13.28 0.35 27.34 0.3 23.44 1.28 15 3.61 2.7 0.75 63.03 0.015 1.26 0.3 25.21 0.125 10.5 1.19 16 3.63 2.6 0.44 51.76 0.15 17.65 0.11 12.94 0.15 17.65 0.85 17 3.45 2.5 0.64 60.38 0.22 20.75 0.04 3.77 0.16 15.09 1.06 18 4.05 2.8 1.312 70.16 0.371 19.84 0.062 3.32 0.125 6.68 1.87 34 19 4.25 2.1 0.95 72.52 0.12 9.16 0.12 9.16 0.12 9.16 1.31 20 4.11 2.9 62.5 0.35 21.88 0.2 12.5 0.05 1.6 21 3.94 2.6 0.7 58.82 0.21 17.65 0.16 13.45 0.12 10.08 1.19 22 3.86 2.7 1.02 70.83 0.19 13.19 0.04 2.78 0.19 13.19 1.44 23 4.25 2.8 0.83 60.58 0.375 27.37 0.04 2.92 0.125 9.12 1.37 24 4.32 2.6 0.8 56.74 0.44 31.21 0.06 4.26 0.11 7.8 1.41 25 3.41 2.4 0.28 26.42 0.38 35.85 0.24 22.64 0.16 15.09 1.06 26 3.78 2.5 0.48 53.33 0.23 25.56 0.15 16.67 0.04 4.44 0.9 27 3.05 2.8 0.86 59.72 0.16 11.11 0.33 22.92 0.09 6.25 1.44 28 3.32 2.1 0.24 40 0.27 45 0.06 10 0.03 0.6 29 4.25 2.6 0.61 43.88 0.51 36.69 0.11 7.91 0.16 11.51 1.39 30 4.15 2.4 0.44 52.38 0.25 29.76 0.11 13.1 0.04 4.76 0.84 Average 3.60 2.38 0.66 55.51 0.26 22.83 0.13 11.30 0.11 10.36 1.16 35 Appendix 04 The correlation between dry biomass and survey factors D1.3 Linear Model Summary R Adjusted R Std Error of Square the Estimate R Square 513 263 237 386 The independent variable is Wtt (kg) ANOVA Sum of Squares df Mean Square Regression 1.489 1.489 Residual 4.167 28 149 Total 5.656 29 F 10.009 Sig .004 The independent variable is Wtt (kg) Coefficients Standardized Unstandardized Coefficients B Wtt (kg) (Constant) Std Error 450 142 2.471 362 36 Coefficients Beta t 513 Sig 3.164 004 6.824 000 Logistic Model Summary R Adjusted R Std Error of Square the Estimate R Square 544 296 270 107 The independent variable is Wtt (kg) ANOVA Sum of Squares df Mean Square Regression 134 134 Residual 319 28 011 Total 453 29 F 11.747 Sig .002 The independent variable is Wtt (kg) Coefficients Standardized Unstandardized Coefficients B Std Error Wtt (kg) 874 034 (Constant) 392 039 The dependent variable is ln(1 / D1.3 (cm)) 37 Coefficients Beta t 581 Sig 25.402 000 9.980 000 Appendix 05 The correlation between the carbon accumulation factor of the D1.3 Linear Model Summary R Adjusted R Std Error of Square the Estimate R Square 439 193 164 404 The independent variable is Wtt (kg) ANOVA Sum of Squares df Mean Square Regression 1.092 1.092 Residual 4.563 28 163 Total 5.656 29 F 6.703 Sig .015 The independent variable is Wtt (kg) Coefficients Standardized Unstandardized Coefficients B Wtt (kg) (Constant) Std Error 648 250 2.842 300 38 Coefficients Beta t 439 Sig 2.589 015 9.473 000 Logistic Model Summary R Adjusted R Std Error of Square the Estimate R Square 439 193 164 114 The independent variable is Wtt (kg) ANOVA Sum of Squares df Mean Square Regression 087 087 Residual 365 28 013 Total 453 29 F 6.692 Sig .015 The independent variable is Wtt (kg) Coefficients Standardized Unstandardized Coefficients B Std Error Wtt (kg) 833 059 (Constant) 347 029 The dependent variable is ln(1 / D1.3 (cm)) 39 Coefficients Beta t 645 Sig 14.118 000 11.778 000 D 1.3 (cm) Linear Model Summary R Adjusted R Std Error of Square the Estimate R Square 439 193 164 404 The independent variable is C (AGB) ANOVA Sum of Squares df Mean Square Regression 1.092 1.092 Residual 4.563 28 163 Total 5.656 29 F 6.703 Sig .015 The independent variable is C (AGB) Coefficients Standardized Unstandardized Coefficients B Std Error C (AGB) 1.296 501 (Constant) 2.842 300 40 Coefficients Beta t 439 Sig 2.589 015 9.473 000 Logistic Model Summary R Adjusted R Std Error of Square the Estimate R Square 439 193 164 114 The independent variable is C (AGB) ANOVA Sum of Squares df Mean Square Regression 087 087 Residual 365 28 013 Total 453 29 F 6.692 Sig .015 The independent variable is C (AGB) Coefficients Standardized Unstandardized Coefficients B Std Error C (AGB) 693 098 (Constant) 347 029 The dependent variable is ln(1 / D 1.3 (cm)) 41 Coefficients Beta t 645 Sig 7.059 000 11.778 000 Pic 1: Field surveys Pic Plot establisment 42 Pic Sample processing 43 ... biomass and carbon accumulation in forests with" was conducted to clarifying this issue ? ?BIOMASS AND CARBON ACCUMULATION IN RHIZOPHORA STYLOSA Griff FOREST AT HOANG TAN COMMUNE, QUANG YEN TOWN, QUANG. .. and is increasing according to the diameter increases, but the ratio of carbon accumulation in leaves is decreasing, while the proportion of carbon in stems and roots are relatively less volatile... concentratios on three objectives: Identify some biomass and carbon accumulation characteristics and of R stylosa Griff forest at the study area; Determine the relationship between biomass and carbon