INTRODUCTION
Forests, covering about 30% of the Earth's land, are vital for life, offering essential services locally, nationally, and globally However, climate change poses significant threats to these ecosystems and the communities that rely on them By 2100, global temperatures are projected to increase by 1.8 to 4 °C, with sea levels rising by 0.75 to 1.5 meters due to greenhouse gas emissions These emissions stem from various sources, including industrial activities, fossil fuel combustion, and environmental pollution Deforestation and forest degradation are major contributors to greenhouse gas emissions, accounting for nearly one-fifth of the total emissions, as highlighted in a report from a climate meeting in Bonn, Germany This issue is not limited to tropical developing countries; recent years have seen an increase in severe forest fires in developed nations like the USA and Russia, leading to the destruction of thousands of hectares of forest and agricultural land.
Forests play a crucial role in environmental protection and provide essential resources such as timber and non-timber products, a concept embraced by many countries, including Vietnam Their significant carbon absorption capacity is vital for mitigating greenhouse gas emissions and combating global climate change The economic value of carbon sequestration can be harnessed through mechanisms like Payment for Environmental Services (PES) and initiatives like Reducing Emissions from Deforestation and Forest Degradation (REDD & REDD+) Additionally, the Clean Development Mechanism (CDM) further supports these efforts in promoting sustainable forest management.
Article 12 of the Kyoto Protocol under the UNFCCC highlights that CO2 absorption by plantations is a vital strategy for reducing greenhouse gas emissions in developing countries While qualitative research underscores the importance of this approach, its implementation in Vietnam represents a pioneering effort towards enhancing environmental benefits.
Recent advancements in Geographical Information Systems (GIS) and Remote Sensing (RS) technologies have significantly enhanced natural resource management, particularly in assessing forest above-ground biomass (AGB) and vegetation structure The increased availability of satellite imagery enables researchers to conduct large-scale image analysis, allowing for effective monitoring and mapping of vegetation biomass and productivity through spectral reflectance measurements Although optical RS does not directly measure AGB, it effectively captures data influenced by vegetation structure, such as crown size and tree density, which correlate with biomass, especially in infrared bands Consequently, RS data has emerged as a reliable method for estimating spatial biomass across extensive tropical regions, offering a cost-effective solution with acceptable accuracy through repetitive data collection with minimal effort.
Cuc Phuong National Park is celebrated for its invaluable forests, which serve as a national treasure These forests offer essential resources, including grazing land for animals, wildlife habitats, water resources, and timber and non-timber products that benefit local communities However, human activities significantly threaten both the quality and quantity of these vital forests Research is underway to assess the carbon storage capacity of these ecosystems.
Understanding biomass in mountain forest ecosystems is essential for assessing the value of these forests based on their carbon accumulation capacity These mountainous regions serve not only as venues for academic exchange but also as vital providers of eco-services that support tourism development Therefore, this study, titled "Using Geospatial Technology to Map Forest Carbon," aims to leverage advanced mapping techniques to enhance our understanding of forest carbon dynamics.
Cuc Phuong National Park" for the student graduation thesis
GOALS AND SPECIFIC OBJECTIVES
Goals
Evaluating the carbon stock in the forests of Cuc Phuong National Park is essential for providing foundational scientific data that can inform sustainable forest management and development strategies in Cuc Phuong commune, Ninh Binh province.
Scope of object
Studying the forests of Cuc Phuong national park in Cuc Phuong commune, Nho Quan district, Ninh Binh province.
Specific objectives
- Mapping the land cover in study site from SPOT 5 imagery
- Estimating and mapping the forest volume in study area from SPOT 5 imagery
- Estimating and mapping the aboveground carbon stock of forests in study area
- Proposing possible solutions to enhance forest management in study area
The forests carbon stock in Cuc Phuong Natinal Park at Cuc Phuong commune over 1,000,000 ton
STUDY AREA AND METHODOLOGY
Study area
The study site includes the forests of Cuc Phuong national park in Cuc Phuong Commune, Nho Quan District, Ninh Binh Provinces (Figure 3.1)
Figure 3.1.1: Map of study area: (a) Land border map of Vietnam (b) Ninh Binh
Province (c) Cuc Phuong commune, Nho Quan Districts
Cuc Phuong National Park, located between Ninh Binh, Hoa Binh, and Thanh Hoa provinces, spans a total area of 22,180 hectares, with 51.1% in Ninh Binh Situated at an elevation of 350 meters, the park experiences an annual average temperature of 20.6°C and receives 1,800 to 2,400 mm of precipitation, contributing to its high relative humidity of around 90% The park's diverse flora features a lush canopy dominated by emergent dipterocarp trees, with notable species including Parashorea stellate, Terminalia myriocarpa, and various evergreen families It hosts over 2,000 vascular plant species, including several endangered and endemic varieties, alongside a rich array of wildlife, supporting approximately 300 bird species, 65 mammals, 37 reptiles, and 16 amphibians.
Data sources
Studying the use inheritance to collect data with the following information:
The SPOT 5 satellite imagery, collected in 2015 within the study area, was supplied by the Institute for Forest Ecology and Environment at the Vietnam National University of Forestry (IFEE) Configuration details of the SPOT 5 imagery are outlined in Table 1.
Table 3.2.1: Technical parameters and properties of the sensors used in this study
500–590 (green) 610–680 (red) 790–890 (NIR) 1580–1750 (mid IR)
Spatial Resolution (m) Pixel Size 1.5 × 1.5 (m/pxl)
Methodology
The proposed methodology is illustrated in Figure 3.2 Software eCognition Developer v8.9, MapInfo Professional 12.5 and ArcGIS desktop 10.2 were used
Figure 3.3.1: The processing steps of study
The study used eCognition v8.9 image analysis software for pre-analysis image SOPT 5 and NDVI for key of image classification eCognition v8.9 image analysis software
eCognition v8.9 image analysis software is utilized for image segmentation, which is the initial phase of object-based image analysis Image segmentation involves dividing an image into distinct regions based on predefined parameters These parameters typically assess the homogeneity or heterogeneity of the regions, facilitating a more detailed analysis of the image content.
The eCognition software utilizes multiresolution segmentation to classify homogeneous areas within forest planning boundaries into smaller sub-plots Key parameters include a scale parameter, shape of 0.1, and compactness of 0.5 The software exports detailed files containing boundary maps of forest plots, along with essential statistical information such as the average value and standard deviation for each channel.
Normalized Different Vegetation Index (NDVI)
The study used NDVI to map the status of forest in Cuc Phuong National Park with 60 sample plots and 65 points in study area NDVI is calculated by following formula:
Where: Nir spectral reflectance values of the near-infrared channel (Band 3), the spectral values of channel Red (Band 2) in Spot 5
Based on Circular No 34/2009/TT-BNN, a typical sample survey method was employed to delineate plots and assess the distribution of forest status subjects within the state's forest basin The survey encompassed 60 plots and established 65 points for comprehensive data collection in the region.
The study involves assessing the status of forest reserves and evaluating the accuracy of map interpretations by utilizing 20 plots and 22 points for accuracy testing The distribution of these plots and secondary surveys varies across different forest states, reflecting the diverse conditions and accessibility of each forest area.
The study area in Cuc Phuong National Park exhibits significant variability in topography and vegetation types, influencing the design of sample plots The optimal size and shape of these plots, which is a 25m x 40m rectangle, balances accuracy, precision, time, and measurement costs, and may vary based on the specific vegetation type present Utilizing GPS for precise location, measurements include tree height and diameter at breast height (DBH) following established regulations for foreign industrial data collection After establishing a 1000m² sample plot, five 4m x 4m sub-plots are created to gather detailed information on shrubs and other features within the area.
Figure 3.3.3: The layout of distribution points
No Name X Y D13(Average) H(Average) Note
The study involves overlaying the analyzed plots and points onto a boundary map, while tagging land cover classes with their corresponding NDVI values A statistical analysis of these NDVI values for each land cover class is conducted to develop a key for image classification.
This thesis focuses on image classification for specific objects within the study area, utilizing defined keywords related to forest conditions It aims to identify essential forest reserves for effective image interpretation and mapping of the forest's status By grouping NDVI values for each object and employing reclassification in the analysis tool, the study enhances the understanding of forest dynamics in the area.
Assessing accuracy is crucial in the image classification process, which can be evaluated through positional or thematic accuracies This study employs a matrix table, a widely used method for evaluating classification agreement in remote sensing The classification precision was verified using 22 points—allocated as 2 for Water, 5 for Plantation, 5 for Bamboo, and 10 for Others—along with 25 plots, with 5 plots designated for each forest type.
The study involved overlaying the forest allocation map with the forest status map to calculate the forest volume for each forest type Utilizing data from 60 previously established sample plots, a comprehensive forest volume map was created, providing valuable insights into the forest's resources.
(Source: The circular 34, Ministry of Agriculture and Rural Development)
The following formula were used to calculate carbon was assessed in five forest carbon pools, which is in accordance with the IPCC 2006 GL (Estrada 2011) These forest carbon pools are:
1 Aboveground vegetation: carbon stocked in live and standing vegetation (trees, shrubs, undergrowth and regeneration)
2 Belowground vegetation: carbon stored in roots
3 Dead wood: carbon stored in standing and fallen dead trees and shrubs
4 Litter: carbon in shed leaves and fine branches
5 Soil: carbon stored as soil organic matter
This article focuses on carbon stock in aboveground biomass, specifically examining aboveground vegetation Utilizing data from forest volume measurements along with Biomass Conversion and Expansion Factors (BCEF), we apply a specific formula to quantify this carbon stock effectively.
Aboveground biomass carbon stock of trees in plot sp, in stratum i at time t=0; t
Merchantable volume of tree l of species j in plot sp in stratum i at time t=0, m3
Biomass conversion and expansion factor for conversion of merchantable volume to total aboveground tree biomass for tree species j; dimensionless Carbon fraction of biomass for tree species j;
L 1, 2, 3, … Nj,sp,i,t sequence number of individual trees of species j in sample plot sp in stratum i at time t
I 1, 2, 3, …M strata j 1, 2, 3 … S tree species t=0 0 years elapsed since start of the project activity
With =0.47 (Andreae and Merlet, 2001; Chambers et al., 2001; McGroddy et al., 2004; Lasco and Pulhin, 2003)
BCEF for nature forests in North Central Vietnam here:
(Sources: 2006 IPCC Guidelines for National Greenhouse Gas Inventories)
Evaluate carbon value for forest environmental services
Amount of CO2 absorbed = Carbon *44/12
- According to the Forest Science Institute of Vietnam
Carbon Price = Amount of CO2 * Price (USD/tonCO2)
- The price in the carbon dioxide:
• Low price: 5 USD / ton CO2
• High price: 11 USD / ton CO2
• $ 1 = 22300 VND exchange rate at the time of the study
RESULTS
Land cover classification map of Cuc Phuong National Park
The study utilized NDVI to classify land cover across eight distinct categories: water, bare land, plantation, grasses, restored forest, poor forest, medium forest, and rich forest GPS technology was employed to mark ten plots representing various surface cover types, including restored forest, poor forest, medium forest, and rich forest, excluding water.
8 points, Others (including bare land, grasses and residential) have 15 points, Plantation have
10 points and Bamboo forest have 10 points
Table 4.1.1: NDVI value for water
Table 4.1.2: NDVI value for others
Table 4.1.3: NDVI value for Bamboo forest based-object
Table 4.1.4: NDVI value for poor forest
Table 4.1.5: NDVI value for restored forest
Table 4.1.6: NDVI value for plantation based-object
(Sources: Cuc Phuong National Park - Studying using data and documents about forest volume of plantation at Cuc Phuong National Park managers in 2016)
Table 4.1.7: NDVI value for medium forest
Table 4.1.8: NDVI value for rich forest
Tables 4.1.1 to 4.1.8 reveal varying NDVI values, including minimum, maximum, and standard deviation for each land cover type Water exhibits an NDVI maximum of approximately -0.09021 and a minimum of around -0.39336 In contrast, rich forests demonstrate the highest NDVI values, ranging from 0.85263 to 0.78427.
I concluded that NDVI ranging were clearly indicated in Table 4.9 (Data collected in Appendixes)
Table 4.1.9: NDVI range for each land cover class in Cuc Phuong National Park
No Land cover classes NDVI
The NDVI values for water were found to range from -0.39336 to -0.09021, indicating strong light absorption in the infrared spectrum In contrast, five forest classes—including bamboo, restored, poor, medium, and rich—showed NDVI values ranging from 0.53498 to 0.85263 The plantation class exhibited NDVI values between 0.24363 and 0.53468, while other land types, primarily consisting of grass and small shrubs, had values ranging from -0.09121 to 0.24263 This reflects a gradual increase in NDVI for these areas compared to water, highlighting the ability of vegetation to absorb red light and reflect infrared light The study area’s plantations are characterized by high density and low shrub presence.
The NDVI values in Cuc Phuong National Park are influenced by the volume and understory vegetation, resulting in relatively high but lower values compared to natural forests Among different forest types, bamboo forests, restored forests, and varying quality forests (poor, medium, and rich) exhibit higher NDVI values due to the presence of natural trees and a limited number of shrubs and regeneration.
Figure 4.1.1: The status forest map in Cuc Phuong commune
To verify the accuracy of this study, I created five plots for each forest type and recorded points for water and other features using a GPS device The accuracy statistics are summarized in Table 4.1.10.
Table 4.1.10: Summarized accuracy of objects
Land cover Water Others Planta- tion
The results showed that error of interpretation on the status of forests is 16.25%, the accuracy of interpretation of the status of forests is 83.75%
The Table 4.1.11 showed the area of land cover classes in study area with eight classes with responding area class
Table 4.1.11: The status forest map in Cuc Phuong commune
No Land cover classes Area (ha) %
According to Table 4.1.11, the area of rich forest dominates the landscape, covering approximately 9,447 hectares, which constitutes 72.07% of the total area In contrast, Water and Bamboo classes are minimal, accounting for only 3.31 hectares (0.03%) and 2.15 hectares (0.02%), respectively The medium forest categories, including Poor and Medium forests, encompass around 1,095 hectares (8.32%), 1,085 hectares (8.28%), and 945 hectares (7.21%) Conversely, Plantation and Restored forests occupy a mere 2% of the total area, with sizes of approximately 327 hectares and 203.74 hectares, respectively.
The forest volume map in Cuc Phuong National Park of Cuc Phuong commune
Table 4.2.1 presents the forest volume of Cuc Phuong National Park, categorized by forest type The analysis, based on results from tables 4.1.4 to 4.1.8, emphasizes five specific classes: rich, medium, poor, restored, and plantation bamboo forests, as other classes such as Water and Other do not have measurable volumes.
Table 4.2.1: Forest volume of Cuc Phuong National Park
Class The average forest volume (m 3 /ha)
The data reveals that the richest forest type boasts a volume of 298.1 m³/ha, while the restored forest has the lowest volume at approximately 41.4 m³/ha Additionally, plantation forests exhibit a volume of 78 m³/ha, medium forests have 177 m³/ha, and poor forests show a volume of 79.3 m³/ha, indicating a consistent decline in forest volume across these categories.
Figure 4.2.1: The forest volume map in Cuc Phuong commune
The map of forest carbon in Cuc Phuong National Park of Cuc Phuong commune
The study calculated the carbon dioxide absorbed in study site, which illustrated in following figure
Figure 4.3.1: The forest carbon map in Cuc Phuong National Park of
Figure 4.3.1 shows that the study site has the highest carbon stock of 133.1 tons in rich and medium forest areas, while water and bare land categories exhibit a carbon stock of 0 tons.
Table 4.3.1: Total forest carbon in Cuc Phuong National Park
The average forest volume (m 3 /ha)
As the result of Table 4.3.3 indicated the total forest carbon stock in Cuc Phuong
Cuc Phuong National Park has a total carbon stock of approximately 1,480,000 tons, with the majority, 1,257,493.81 tons (85.52%), coming from rich forests The carbon stocks for medium, poor, and plantation forests are 117,383.84 tons (7.98%), 69,394.54 tons (4.72%), and 17,982.83 tons (1.22%) respectively The restored forest contributes a modest 8,126.96 tons (0.55%) Other land types, such as water bodies, bare land, and bamboo forests, were not included in the carbon stock assessment, which specifically focused on the forest volumes of rich, medium, poor, plantation, and restored forests.
Mapping the Carbon Dioxide absorbed
The study calculated the carbon dioxide absorbed in study site, which illustrated in following figure
Figure 4.4.1: The CO 2 absorbed map in Cuc Phuong commune Table 4.4.1: The CO 2 absorbed in Cuc Phuong National Park at Cuc Phuong Commune
With formula: Amount of CO2 absorbed = Carbon *44/12 The figure 4.4.1 indicated the CO2 absorbed in forest at Cuc Phuong commune with the highest value at 488.04 ton/ha
27 for rich forest and the lowest value is 146.26 ton/ha (represent 144.87 ton/ha) for restored forest
Evaluate carbon dioxide value for forest environmental services
Table 4.4.2: Evaluate carbon dioxide value for forest environmental services
CO 2 USD/ton CO 2 per ha
Ton/ha Low price High price
Figure 4.4.2: Figure carbon absorb value of different forest types in CPNP
USD/ton CO2 per ha USD/ton CO2 per ha
The amount of carbon absorption and corresponding prices for different forest types are illustrated in the figure Rich forests have the highest carbon absorption, valued at $2,440.17 per hectare, followed by medium forests at $1,982.75 per hectare and poor forests at $1,161.60 per hectare In contrast, plantation and restored forests exhibit significantly lower values, priced at $1,008.15 and $731.20 per hectare, respectively.
The primary factor contributing to the differences among forest types is their uneven age distribution Variations in growth index and density result in differing capacities for carbon absorption.
4.3 Proposing solutions to improve the management of forests in Cuc Phuong commune
Cuc Phuong National Park in Hanoi faces significant challenges regarding forest volume and carbon stock, including inadequate land use planning and ineffective management plans The park's extensive old forest has reached its peak growth, leading to degradation, while its large land area poses a high erosion risk during heavy rains To address these issues, the study proposes several solutions aimed at enhancing forest quality and improving carbon stock management in Cuc Phuong Commune.
The state must clearly define the rights and responsibilities of individuals or organizations assigned forest land and resources, particularly regarding timber usage Those managing these forest areas will be held legally accountable for any violations It is essential to enhance inspections and enforce strict controls to address unlawful forest encroachment and unauthorized changes in land use.
The application of information technology into management and monitoring changes in forest resources processes such as organizations and units who own protection forest should
29 participate fully in managing and monitoring changes in forest resource by using database system on the computer at the local and the whole province
To foster sustainable growth, it is essential to promote investment in policy support that integrates ecotourism development with forest protection initiatives, sourcing funds from both domestic and international avenues Additionally, prioritizing the education and awareness of the younger generation about the vital role of forests in enhancing human life and the environment is crucial for long-term conservation efforts.
A study conducted in Cuc Phuong National Park focused on mapping the forest carbon in Cuc Phuong commune, utilizing three distinct maps: one for forest volume, another for forest carbon, and a third for the carbon dioxide absorbed in the area.
The first map detailing the forest volume of Cuc Phuong National Park covers a study area of 13,109.84 hectares and categorizes the forest into eight classes: water, plantation, bamboo forest, restored forest, poor forest, medium forest, rich forest, and others However, the focus of the study is on five forest types with the highest volume, particularly the rich forest, while the water, bamboo, and other categories do not contribute to the forest volume assessment The restored forest exhibits the lowest volume value due to its ongoing replantation and recovery efforts.
The thesis presents the mapping of carbon stock in the study area, revealing a total forest carbon of approximately 1,480,000 tons Notably, the highest carbon value recorded is 133.10 tons per hectare, which exceeds the total carbon of around 130 tons per hectare and 1,023,726 tons of carbon reported in Kim Boi District, Hoa Binh Province, according to Assoc Prof Dr Tran Quang Bao.
2013, identified the carbon stock of forest classes in Kim Boi District, Hoa Binh province
This thesis presents a comprehensive mapping of carbon dioxide absorption in Cuc Phuong National Park, revealing a significant total CO2 absorption in Cuc Phuong Commune, with peak values reaching approximately 488.04 tons per hectare.
Cuc Phuong National Park is characterized by its high carbon volume and significant carbon dioxide absorption, making it an essential natural resource The park features a diverse ecosystem, primarily consisting of evergreen broadleaf limestone forests that are rich in biodiversity Compared to other studies, Cuc Phuong stands out for its abundant natural woodlands, highlighting the urgent need for conservation efforts to protect its unique wildlife and plant species for future generations.
The study's findings highlight the effectiveness of remote sensing technology and high-resolution satellite imagery in forest investigations, achieving an impressive interpretation accuracy of 83.75% for mapping forest type changes and quality Utilizing SPOT 5 satellite images, the primary land cover and land use categories identified in Cuc Phuong commune include rich, medium, poor, restored, bamboo, plantation forests, water, and others The total study area spans 13,109.84 hectares, with an estimated total forest carbon stock of 1,480,000 tons.
The study reveals that the rich forest spans 9,447.62 hectares, accounting for 72.07% of the total area, with a forest volume of 298.1 m³/ha and storing 1,257,493.81 tons of carbon, which represents 85.52% of the total carbon stock In contrast, the restored forest shows the lowest metrics, with a volume of 203.74 m³/ha and a carbon storage of 8,126.96 tons, representing just 0.55% of the total.
The carbon stock and CO2 absorbed for rich forest in forest at Cuc Phuong commune with the highest value around 133.1 ton/ha and 488.04 ton/ha, respectively
The study faces several challenges, including insufficient time and resources for extensive field data collection, as well as my limited expertise To address these issues and enhance outcomes, future research should focus on gathering additional information for effective planning, increasing the number of sample plots across various forest types, and improving users' proficiency in geospatial technology.
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No Commune X Y D13(Average) H(Average) Note