ACKNOWLEDGMENT During months of conducting this working, I gained availed of encouragements and assistance from many people without whom this thesis would have never been conducted. First and foremost, I would like to express my gratefulness to Dr. Nguyen Hong Hai for constant support to each step of my thesis working, giving me motives and enthusiasm as well as a wealth of knowledge. The guidance was really clear with vivid images and detailed illustration, which facilitated me a lot in thesis project, in another place, I would like to thank the Administration of Vietnam Forestry University, Faculty of Forest Resources and Environmental Management, Department of Environmental with sincere gratitude for enabling us all best to complete the graduation thesis.
Also, I sincerely express my thankfulness to many local people and authorities, both of whom untold assist me in collecting data and many other related procedures Finally, I also thank my family and all my friends, partners for best effort me the best facilitations to accomplish the thesis within expectations. Thank you! Xuan Mai, 2nd October 2019 Student Nguyen Thi Hong Nhung TABLE OF CONTENT ACKNOWLEDGMENT. 1 TABLE OF CONTENT. 2 LIST OF TABLES.
4 LIST OF FIGURES. Forest and forestry in the world. Forest and forestry in Viet Nam. Low Impact Logging (LIL).
Studying in Forest structure. 4 CHAPTER 2 - GOALS, OBJECTIVES AND METHODOLOGY. 7 CHAPTER 3 - NATUAL AND SOCIO-ECONOMIC CONDITION OF THE STUDY REGION. Socio-economical condition.
15 CHAPTER 4 - RESULTS AND DISCUSSIONS .1 Forest stand properties. Main characteristics of two forest stands. Characteristics of tree individuals at life stages. Tree species composition.
Tree species composition of two plots. Tree species compositions at life stages. Species diversity in two plots. Species diversity at life stages in two plots.
Distribution of trees by life stages. Spatial distribution of dominant tree species. Some recommendations for sustainable forest management at Truong Son Forest Enterprise. Forest structure stand.
Proposing management solutions. 38 REFERENCE APPENDIX LIST OF TABLES Table 4. Structural characteristics of tree species in LIL plot. Structural characteristics of tree species in CL plot.
The most dominant tree species in LIL plot. The most dominant tree species in CL plot. The most dominant tree species base on life stages in two plots. Summary of diversity measures for the two plots.
Summary of diversity measures for the study plots at life stage levels. 28 LIST OF FIGURES Figure 3.1 The location of the study site in Quang Binh Province .2 Climate graph by month in Quang Ninh district, Quang Binh province .3 Average temperature Quang Ninh district, Quang Binh province .1 Frequency of tree individuals and tree DBH in LIL plot .2 Frequency tree individuals and tree DBH in CL plot .3 Spatial distributions of life stages in LIL plot analyzed by the Ripley’s L function.4 Spatial distributions of life stages in CL plot analyzed by the Ripley’s L function.5: Spatial distributions of seven dominant species in LIL plot analyzed by the Ripley’s L function.6: Spatial distributions of seven dominant species in CL plot analyzed by the Ripley’s L function. 33 ABSTRACT This study has aimed to show some structural characteristics of tropical broadleaves that stands under the effect of conventional and low impact logging in Truong Son Forest Enterprise, Quang Binh Province. A total of 2 plots of 100m x 50m each placed in two forest states were surveyed species name, diameter, height, relative coordinates.
We calculated and described structural parameters such as DBH dominance and species index, tree density, frequency distribution, and tree diameter and height data by Paleontological Statistics and Microsoft Excel softwares. The results show that: most of studied species were found highly mixed with other species. The number of trees per life stages and density of the forest state conventional logging concentrated on all diameter levels form sapling, juvenile, and adult, suggesting that this forested state will focus on all trees of economic value in Truong Son Forest Enterprise, while in the low impact logging concentrated mostly on diameter of more than 30 cm to keep the immature seedlings alive for future crops. The number of trees in each life stage is inversely proportional to each other, the number of individuals decreases when the diameter becomes larger.
Species composition were very seriously affected because number of species in the life stage all changed. The most important species found in both two forest states were G. About spatial distribution of two plot mainly clustered distribution but some species that are completely randomly distributed without the cluster distribution like G. The spatial structural parameter offers direct information and valuable about spatial structure of forest stand.
That information can be used in thinning of sustainable forest management, modeling and restoration. Key words: Forest enterprise, forest stand properties, LIL plot, CL plot, tropical broadleaves, tree species composition, tree species diversity, spatial distribution. Forest and forestry in the world Geographically, tropical rain forests are currently found in Southeast Asia, Central and South America, and Central and West Africa (Richards, 1996; Whitemore, 1998), with Southeast Asia containing the second largest tropical rain forest with an area of about 2. Globally, around 52% of the total forests are in tropical regions and they are known to be the most important areas in terms of biodiversity (Lewis et al., 2009) Tropical forests play a crucial role in three respects regarding the well-being of mankind.
Tropical forests provide many goods and ecosystem services, such as prevention of soil erosion and preservation of habitats for plants and animals (Anbarashan M. Socially, millions of people who are living in or around tropical forests depend on them for the many forest products and environmental services gained (Naughton- Treves and Weber, 2001). Economically, they possess a main source of energy in the form of fuel wood, wood, and traditional medicines: they also provide timber and non- timber forest products. It is therefore essential to understand the structures and species diversity of tropical forests in order to find a way to maintain, protect, and develop those ecosystems, Biotic factors such as seed quality, seedling survivorship, and recruitment are important in maintaining the tree composition of tropical forests (Connell 1971).
Overexploitation has resulted in the rapid loss of forests and is recognized to be one of the biggest environmental and economic problems around the world (Mani and Parthasarathy 2006). The natural forest is disappearing at alarming rates worldwide, reducing annually by 1–4% of their current area (Laurance 1999). Relatively increased anthropogenic pressures have led to agricultural expansion and overgrazing of livestock (Anitha et al 2010). Forest and forestry in Viet Nam Forest vegetation in Vietnam is diverse as a result of different climatic conditions and topographic/latitudinal variations (Thai, 1978; USAID, 2013).
Vietnam has at present 13.7 million hectares of forest covering 41.45 % of its total land area; of these, 10.2 % ) are natural forests (FPD, 2013) with 4.15 million ha is production forest and State Forest Enterprises (SFE) manage that can be classified 2 into eight major forest groups: close-mixed evergreen broad-leaved rainforest, semi- deciduous mixed forest; mixed limestone forest; coniferous and mixed coniferous broad- leaved forest; sparse forest, seasonal deciduous forest and Dipterocarps- dominant forest; mangrove forest; Melaleuca forest (i., forest on alum land); and bamboo and mixed timber-bamboo forest. As it is the case concerning other tropical forests, Vietnam's forests are high in diversity, and up to hundreds of different tree species can be found within one hectare (Whitmore, 1990; Richards, 1996). The result is a high level of biomass and productivity (Vanclay, 199la: Le, 1996; Sam, 2004; Gunter et al. Conventional Logging (CL) CL is a term used to identify methods commonly used in an area to move logs from stump to mill.
It brings the highest economic efficiency but causes serious impacts on forest structure such as large areas of forests are often destroyed in order to remove the few selected logs. One felled tree also often brings down other trees with it by falling into them on its way to the ground. This creates large holes in the canopy which impacts the habitat in many ways and complete regeneration of this gap can take hundreds of years, if it is able to regenerate at all. These gaps break habitats into smaller fragments, referred to as fragmentation, which threatens many species with endangerment or extinction.
Low Impact Logging (LIL) LIL is considered better practice than clear-cutting (Gatti et al. It is increasingly being accepted as an approach to protecting forest integrity and enabling the proper use of resources. This silvicultural technique is widely used because the growers want to keep the immature seedlings alive for future crops. In other words, after the law impact logging, the rest retained the main structural elements of the forest as well as the various ecological niches an of pre-harvested values (Nzogang, 2009).
Damage caused by LIL plot (LIL) was assessed in 18 plots 1 ha each in a terra firm rain forest of Eastern Amazon (Brazil, Paragominas). Mean logging intensity was 6 trees ha−1 and the resulting commercial volume 21 m³ ha−1. On average, logging damage affected 16% of the original stand while skid trails occupied 7% (661 m² ha−1) of forest soil area. Canopy openness doubled to a mean of 11%.
Of the variables 3 studied, “number of trees harvested or felled per plot” gave the best correlation to “proportion of damaged or destroyed trees”. Damage to each diameter class was distributed in accordance with relative abundance of trees (DBH ≥ 20 cm) in the original population before logging, suggesting that all diameter classes were affected equally (P Sist, FN Ferreira, 2007). Tree injury and death from RIL in contrast, was substantially lower (30.5%) than from conventional methods (48. Studying in Forest structure However, the majority of researching tropical forests in developing countries are still limited, consequently, the stand structures and species diversity of those forests are often insufficient for management.
Sustainable management of these forests requires a good knowledge of all the natural forest resource; this knowledge could be reliable only through studies of the forest environment (Hien Thu Thi Cao, Hong Hai Nguyen, 2019). Forest structure plays an important role in forestry research. Forest structure greatly impacts the habitat of fauna and flora species. Complex forest structures diversity microclimates, niches and habitats for maintaining the majority of terrestrial biodiversity.
Forest structure is the key to understanding and determining ecosystem functions. The structure and distribution of forest patches regulates habitat structure, wildlife distribution and determines the delivery of ecosystem services. In other words, the structure directly affects the biodiversity, erosion control, water availability and carbon storage functions of the forest. Changing forest structure leads to changes in carbon stocks and evapotranspiration.
Indicators of forest structure are also a component that should be considered for sustainable forest management. Species diversity can be influenced by tree diameter distributions. Forest structure classifications can be practical and meaningful for ecological assessment and monitoring (Hung Manh Bui, 2018) Species diversity, species richness, and biodiversity are widely used terms in ecology and natural resource management. In general, the species diversity of a community is made up of two components: species richness (or the number of species present) and the evenness, species equitability species (Pielou, 1966; Patil and Rao, 4 1994), or abundance of each Hamilton (2005) reports that there have been two approaches to measuring species diversity: the first involves constructing mathematical indices broadly known as diversity indices, and the second requires comparing observed patterns of species abundance to theoretical species abundance models.
Species diversity indices take two aspects of the community into account: species richness and evenness (Hamilton, 2005). In this study, species richness, the Shannon-Wiener the Simpson indices, and the diversity profile are computed to evaluate and compare the diversity of tree species in the for study sites.