Application of remote sensing and gis for forest cover change detection in ngoc hien district, ca mau province (1990 2016)

ACKNOWLEDGEMENT The success and result of this project required a lot of guidance and assistance from many people and I am extremely fortunate to have this all along the completion of my project work Whatever I have done is only due to such guidance and assistance and I would not forget to thank them A special thanks to Assoc Prof PhD Phung Van Khoa, who advised us throughout this study Without his enthusiasm and advice, it is unlikely this work would have been completed and for that we are truly grateful I am thankful to and fortunate enough to get constant encouragement, support and guidance from teachers in Vietnam National University of Forestry I would like to thank the staffs and foresters in the Dat Mui and Nhung Mien Mangrove Forest Management Board for their support and assistance Students: Trinh Nam Phong ABSTRACT Ngoc Hien is known as the southernmost rural district of Ca Mau, Vietnam with the extensive mangrove forest areas and availability Therefore, the detection of forest cover change annually is very necessary in order to have sensible management methods Through researching, we recognized that the flora in Ngoc Hien is quite abundant and mostly is mangrove species The mangrove forest area increases continuously through periods 1990 – 1995 – 2016 The forest lost area decreased significantly from 1995 to 2016 It proves that local people in Ngoc Hien have had more awareness about protecting forest The application of RS and GIS to detect mangrove forest cover changing is very useful It helps us to shorten the time to research and give us the high accurate results Keywords: Remote sensing; Forest Cover Change; application of GIS; construct map… ACRONYMS RS: Remote Sensing GIS: Geographical Information System TM: Thematic Mapper MSS: Multi-spectral Scanner SPOT: Satellite Probatoire d'Observation de la Terre NDVI : Normalized Difference Vegetation Index ENVI : Environment for Visualizing Images CONTENTS CHAPTER I INTRODUCTION CHAPTER II LITERATURE REVIEW 2.1 General definition about Remote Sensing and GIS 2.2 Application of Remote Sensing and GIS CHAPTER III OBJECTIVES, CONTENTS AND METHODOLOGY 3.1 Goal and objectives: 3.1.1 Goal: 3.1.2 Objectives: 3.2.Contents: 3.2.1 Collecting materials related to the status of forest cover in Ngoc Hien (Ca Mau) in the period (1990 - 1995- 2016) 3.2.2 Construct map and detect forest cover change in Ngoc Hien in the period (1990 - 19952016) 3.2.3 Propose some solutions for effective and sustainable forest managing and using in Ngoc Hien (Ca Mau) 3.3.Methodology: 3.3.1.Collecting materials related to the study 3.3.2.Image Acquisition and Pre-processing 3.3.3.Software 3.3.4.Image Interpretation 3.3.5.Fieldwork 21 CHAPTER IV NATURAL AND SOCIOECONOMIC CHARACTERISTICS OF THE STUDY SITE 24 4.1 Natural characteristics 24 4.1.1 Geography 24 4.1.2 Terrain 25 4.1.3 Climate 25 4.1.4 Hydrology 25 4.1.5 Natural Resources 25 4.2 Socioeconomic characteristics 26 4.2.1 Social characteristics 26 4.2.2 Economic characteristics 26 4.3 Mangroves and roles of mangroves in Ngoc Hien- Ca Mau 26 Chapter V RESULTS 28 5.1 Results of fieldwork combine with interpret Landsat image 28 5.2 Forest cover change map in periods 1990 – 1995 – 2016 37 5.2.1 Forest cover change map in 1990 37 5.2.2.Forest cover change map in 1995 38 5.2.3 Forest cover change map in 2016 40 5.3.Reason causing forest cover change in Ngoc Hien district and solutions 41 5.3.1 Reason causing forest cover change in Ngoc Hien district 41 5.3.2.Propose solutions 42 Chapter VI CONCLUSION, LIMITATION AND FUTHER STUDY 44 6.1 Conclusion 44 6.2 Limitation and further study 44 REFERENCES LIST OF TABLES Table 3.1 Landsat Satellite Images used in the study Table 3.2 Image Classification 17 Table 3.3 Matrix to assess the accuracy 22 Table 5.1 Area of lost and exploited forest Statistic in 1990 37 Table 5.2 Area of lost and exploited forest Statistic in 1995 38 Table 5.3 Area of lost and exploited forest Statistic in 2016 40 LIST OF CHARTS Chart 5.1 Forest cover change in 1990 37 Chart 5.2 Forest cover change in 1995 39 Chart 5.3 Forest cover change in 2016 40 LIST OF FIGURES Figure 3.1 Defaults setup Figure 3.2 Import data Figure 3.3: Change the default and add bands created 10 Figure 3.4 Modify images 11 Figure 3.5 Layer stacking 12 Figure 3.6 Process of Creating Subset Image 13 Figure 3.7 Image of the study area after cutting 14 Figure 3.8 Edit signature 15 Figure 3.9 Assessing the quality of image choosing 16 Figure 3.10 Image before purifying 18 Figure 3.11 Image after purifying 19 Figure 3.12 Exclude subjects out of the study area 20 Figure 3.13 Processing of changing from Raster into Vector 21 Figure 3.14 Overall steps to collect information 22 Figure 3.15 Overall steps to process information 23 Figure 4.1 The Study Area 24 Figure 5.1 Forest Cover Change detection in 1990 38 Figure 5.2 Forest Cover Change detection in 1995 39 Figure 5.3 Forest Cover Change detection in 2016 41 LIST OF PHOTOS Photo 5.1 Photo in the field 28 Photo 5.2 Photo in the field 29 Photo 5.3 Photo in the field 30 Photo 5.4 Photo in the field 31 Photo 5.5 Photo in the field 32 Photo 5.6 Photo in the field 33 Photo 5.7 Photo in the field 34 Photo 5.8 Photo in the field 35 Photo 5.9 Photo in the field 36 CHAPTER I INTRODUCTION Besides getting benefits from forest exploitation and using, human activities such as agriculture, mining, deforestation and construction have caused many impacts on natural resource and environment Urban growth and its associated population increase is a major factor, which has altered natural vegetation cover This has resulted in a significant effect on local weather and climate Nowadays, we are facing with regression of natural resources and environment Economic development combining with protecting environment and natural resources to develop sustainably is an urgent problem To this mission well, investigation monitoring - and assessment task is one of the most important task Although each year there are some reports about status of forest cover change, almost these reports based on constructing map by rudimentary methods It is very complex and time consuming and we cannot find out most recent information from them because time for summarizing and constructing is long, then the information in map is backward and not exact While a good map is required exact form, quick time and updating information Therefore, we need new methods to make good maps Nowadays, the development of science and technology, especially the births of Geographical Information System (GIS), Remote Sensing (RS) and satellite images, helps us so much to research forest cover change, study and propose some methods to manage the natural resources and environment without direct contacts Remote Sensing (RS) information with many advantages like synchronous and updating information, broad covering ability and covered everywhere in the Earth… and with rapid development of technology such as supply information rapidly, exactly… brings to us authentic values of mapping methods in researching relationships and reciprocal impacts of some phenomenon, subjects such as forest cover change, forest resources change… Geographical Information Systems (GIS) can collect, Note: Investigator: Trinh Nam Phong Position: Household Tran Van Tap Latitude X: 8.621673 Province: Ca Mau Longitude Y: 104.935414 District: Ngoc Hien Exploit area: 0.3 (ha) Commune: Vien An Dong Dominant species: Duoc, Mam, shrubs Exploit date: 13/06/2016 Average silvicultural targets: D(cm): 12 H(m): 12 N(tree/ha): 3100 Before Exploit After Exploit Photo 5.4 Photo in the field 31 Note: Investigator: Trinh Nam Phong Position: Household Nguyen Van Nam Latitude X: 8.61707 Province: Ca Mau Longitude Y: 104.951013 District: Ngoc Hien Exploit area: 0.7 (ha) Commune: Vien An Dong Dominant species: Duoc, Mam, shrubs Exploit date: 10/07/2016 Average silvicultural targets: D(cm): 12 H(m): 11 N(tree/ha): 2900 Before Exploit After Exploitat Photo 5.5 Photo in the field 32 Note: Investigator: Trinh Nam Phong Position: Household Tran Van Khuoi Latitude X: 8.617413 Province: Ca Mau Longitude Y: 104.971935 District: Ngoc Hien Exploit area: 0.5 (ha) Commune: Vien An Dong Dominant species: Duoc, shrubs Exploit date: 04/07/2016 Average silvicultural targets: D(cm): 12 H(m): 13 N(tree/ha): 3300 Before Exploit After Exploit Photo 5.6 Photo in the field 33 Note: Investigator: Trinh Nam Phong Position: Household Nguyen Hoang Phieu Latitude X: 8.630811 Province: Ca Mau Longitude Y: 104.845354 District: Ngoc Hien Exploit area: 0.4 (ha) Commune: Vien An Dominant species: Duoc, shrubs Exploit date: 27/07/2016 Average silvicultural targets: D(cm): 10.5 H(m): 12 N(tree/ha): 2200 Before Exploit After Exploit Photo 5.7 Photo in the field 34 Note: Investigator: Trinh Nam Phong Position: Household Nguyen Thi Be Na Latitude X: 8.656747 Province: Ca Mau Longitude Y: 104.870701 District: Ngoc Hien Exploit area: 0.1 (ha) Commune: Dat Mui Dominant species: Duoc, shrubs Exploit date: 19/07/2016 Average silvicultural targets: D(cm): 10.7 H(m): 11 N(tree/ha): 2100 Before Exploit After Exploit Photo 5.8 Photo in the field 35 Note: Investigator: Trinh Nam Phong Position: Household Ta Van Toan Latitude X: 8.64189 Province: Ca Mau Longitude Y: 104.865252 District: Ngoc Hien Exploit area: 0.5 (ha) Commune: Vien An Dominant species: Duoc Exploit date: 15/08/2016 Average silvicultural targets: D(cm): H(m): 11 N(tree/ha): 3100 Before Exploit After Exploit Photo 5.9 Photo in the field 36 5.2 Forest cover change map in periods 1990 – 1995 – 2016 5.2.1 Forest cover change map in 1990 Class Area(hectare) Forest 12999.3 Forest lost 4369 Water 18585.5 Total 35953 Table 5.1 Area of lost and exploited forest Statistic in 1990 The Table 5.1shows that the area of mangrove forest is 12999.3 hectare makes up 36.15% of the total area of the study site; the area of lost forest is 4369hectare (12.2%); the area of water around the study site is 18585hectare (51.65%) These interpreted results base on the data interviewed about exploitation and losing forest history in the points that we investigate in fieldwork, so these results are not right absolutely Area(hectare) 36% Forest Forest lost 52% Water 12% Chart 5.1 Forest cover change in 1990 Forest cover change detection map in 1990: 37 Figure 5.1 Forest Cover Change detection in 1990 5.2.2 Forest cover change map in 1995 Class Area(hectare) Forest 14132.4 Forest lost 4595.3 Water 17125.5 Total 35853.2 Table 5.2 Area of lost and exploited forest Statistic in 1995 The Table 5.2 shows that the area of mangrove forest is 14132.4hectare makes up 39.42% of the total area of the study site; the area of lost forest is 4595.3 hectare (13%); the area of water around the study site is 17125.5 hectare (47.58%) These interpreted results base on the data interviewed about exploitation and losing forest history in the points that we investigate in fieldwork, so these results are not right absolutely 38 Area(hectare) 39% 48% Forest Forest lost Water 13% Chart 5.2 Forest cover change in 1995 Forest cover change detection map in 1995: Figure 5.2 Forest Cover Change detection in 1995 39 5.2.3 Forest cover change map in 2016 Class Area(hectare) Forest 22522.63 Forest lost 1920.7 Water 701.3 Total 25144.63 Table 5.3 Area of lost and exploited forest Statistic in 2016 The Table 5.3 show that the area of mangrove forest is 22522.63 hectare makes up 89.58% of the total area of the study site; the area of lost forest is 1920.7 hectare (7.64%); the area of water around the study site is 701.3 hectare (2.78%) Area(Hectare) 8% 3% Forest Forest lost Water 89% Chart 5.3 Forest cover change in 2016 Forest cover change detection map in 2016: 40 Figure 5.3 Forest Cover Change detection in 2016 5.3 Reason causing forest cover change in Ngoc Hien district and solutions 5.3.1 Reason causing forest cover change in Ngoc Hien district From the results, we can see that mangrove forest area through period of 1990-19952016 changed In specific, from 1990-1995 mangrove forest area changed from 12999.3 hectares to 14132.4 hectares; and from 1995 to 2016 it changed from 14132.4 hectares to 22522.63 hectares However, within 16 years the total forest lost area in Ngoc Hien is 10884.7 hectares After researching, we found some reasons of forest cover changing in Ngoc Hien district: - Land-use transformation: The demand of shrimp exportation increases while the supply sources of shrimp by small-scale catch decrease Therefore, in the early years of the 21-century, in almost of coastal areas in Vietnam, mangrove forests and natural protection 41 forests were replaced by aquatic zones In addition, they changed forest area to build tourist areas or resorts… - Over exploitation: Nowadays, over exploitation of forest is a worrying problem with forest resources in Vietnam in general and mangroves forest in particular This is the direct cause leading to the degradation of forest quality and biodiversity In addition, reason leading to degradation of forest area is also by human daily activities such as deforest for firewood and timber for building materials Other factors affecting to the mangrove forest is natural factors like sea level rise, acid rain, climate change, and forest fire… 5.3.2 Propose solutions From the forest cover change status we showed above, we propose some solutions for diminishing deforestation situation and improve the management working in Ngoc Hien district: Prevent deforestation: To that we must have the concrete project for aquaculture zones and control the increasing in area of these zone Therefore, we can keep the balance between developing economic and protecting the environment and forest area not only in Ca Mau but also in provinces belongs to The Mekong River Delta Specific solutions is that completing irrigation infrastructures to service aquaculture, improving qualification for producers, invest money and widen consuming market to increase the income for local people from that we can limit deforestation Beside, we need to combine forest protection with economic development by some strategy such as create job for local people (give priority the unemployed that come from rural areas); encourage tourist industry combine with ecotourism, national park to increase the income of local people and improve awareness of people in forest protection Reinforce and widen Natural Resource Conservation Areas: Nowadays some mangrove forests are changed into national parks or nature reserve areas These forests are 42 special use forest It means that these forests are unexploited and are only for protecting With some special use forests that are plantation forest, there should be some silviculture methods timely in order that forest can grow and develop healthy In addition, to use mangrove forest efficiently and overcome some bad effects by climate change as well as impacts of human on mangrove forest in the future, we need to consider about some solutions: Mangrove forest plays an important role in absorbing CO2 ; reducing greenhouse effect so we need to grow forest on fallow land of mangrove forest On average, hectare of mangrove forest can absorb about 1.5 tons of CO2 per year with Duoc (Rhizophoraceae) forest 30 years old (Ong, 1993, 2002) Shrimp hatching inside mangrove forest: that solution is a combination of natural protection and economic growth because if we apply this we can supply a necessary area to create a stable environment and natural food for shrimp from the volume of fall leaf Some mangrove forests need to be researched to identify forest regeneration cycle and apply forest regulation to replace some old forests by young forest From that, we can take full advantage of wood per year to supply coal made by Duoc (Rhizophoraceae) to export and supply for Vietnam market Improve awareness of local people; educate them about the important value of mangrove ecosystem to make them have responsibility about forest protection Explain to them that forest is not fallow land or forest has no economic value Improve personal skill of technicians to approach GIS technology in mangrove forest management 43 Chapter VI CONCLUSION, LIMITATION AND FUTHER STUDY 6.1 Conclusion The application of remote sensing and GIS with other data related to constructing forest cover status map or forest cover change map is very diversified and abundant Its advantage is displaying visually and objectively; editing rapidly; easy to use in analyzing and predicting mangrove forest change in some regions Therefore, the changing of forest cover is not only presented as data but also as maps Processing Landsat images and assessing forest area change in coastal area by using remote sensing and GIS are the standard for mangrove forest management in coastal area Whereby, we can show the relationship between forest area change and erosion in coastline In general, with mangrove forest, it is very hard to survey and move It is very time consuming because canopies limit our view Application of remote sensing and GIS helps us so much to save time to assess the study area The results are also objective and comprehensive The study area is conserved relatively well so the mangrove forest area increases continuously through periods 1990 – 1995 – 2016 It proves that local people have had more awareness about protecting forest 6.2 Limitation and further study Although we obtained some results, the study also has some limitations The study site is very large, far and the traffic is mostly waterway so it is very difficult for us to survey We just surveyed in three communes Vien An Dong, Vien An and Dat Mui Because we have scanty money and time, our field trip lasted weeks In addition, our experience is not much, so it also affects our survey data and results To overcome the shortcomings and achieve better results, further study should increase the number sampling points to increase the authentication and verification for the interpretation Besides, the author should spend more time for fieldwork in order to research the study area more carefully 44 REFERENCES Hua Phuc Hoang (2012), Applying Remote Sensing and GIS to construct map of forest cover status in Cao Ky, Cho Moi, Bac Kan Thai Nguyen University of Agriculture and Forestry Pham Viet Hoa (2012), Applying Remote Sensing and GIS to detect mangrove forest change Hanoi University of Mining and Geology Nguyen Thi Tho (2009), Applying Remote Sensing and GIS to detect forest area change in Dao Tru, Lap Thach, Vinh Phuc Le Thi Thuy Van (2010), Applying Remote Sensing and GIS to detect land use change in Vinh Trai, Lang Son (2003-2008) Hanoi University of Agriculture Tran Anh Tuan (2012), Detecting forest cover change in Con Dao, Ba Ria Vung Tau by using remote sensing and GIS College of Natural Sicences Sajjad et al (2015), Application of Remote Sensing and GIS in Forest Cover Change in Tehsil Barawal, District Dir, Pakistan University of Haripur, 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