The study established five plots for each forest type; forest types include old growth forest, 20 years after logging and 10 years after logging.
Silviculture RELATIONSHIPS AND SPATIAL DISTRIBUTION OF SPECIES IN NORTH ZAMARI RESERVE FOREST, THAYARWADDY, MYANMAR Myo Min Thant1, Bui Manh Hung2 Good Neighbors International, Myanmar Vietnam National University of Forestry SUMMARY The study shows that dominant species of the old-growth forest is mainly Lanea coromandelica, Terminalia crenulata, Stereospermum colais, etc The dominant species of the forest after 20 years of exploitation are usually Berrya mollis, Lagerstroemia speciosa… and the dominant species for the forest after 10 years of logging is Vitex pubescens, Cratoxylum ligustrinum, Xylia xylocarpa The results of spatial relationship analysis between dominant species show that for the old-growth forest, the species tend to grow close together at a distance between to 2.2 m, but with distance greater than 2.2 m, the species are repulsive In contrast, the forest after 20 years and 10 years of logging, species are repulsive and attractive, respectively In the old-growth forest, the spatial distribution of species is clustered for any distance from to 3.5 m In contrast, the spatial distribution for forests after 20 and 10 years of logging is clustered at any distance A rate of good trees is old-growth forest is the highest They are often in the top storey And then, the forest after 20 and 10 years of exploitation are lower, respectively On the contrary, the rate of the medium and bad trees is greatest in the forest after 10 years recorvery And then gradually decrease in forest after 20 years restoration and old-growth forests Keywords: Dominant species, ecological species relation, Myanmar, North Zamari reserve, spatial distribution I INTRODUCTION Forest structure is a very important basis for understanding the past, present and determining future functions of forest ecosystems Forest structure also has a great influence on the habitat of plant and animal species in forest ecosystems Forest structure is also the basis for proposing silvicultural solutions and sustainable forest management solutions (Hung, B.M., 2016; Lamprecht, H., 1989) Typically, the relationship between tree species is usually divided into three main groups: resistance, minor resistance and nonresistance Understanding the relationship between natural forest species is essential for adjusting species compositions in plant communities, proposing silvicultural and decisive for selecting and coordinating species for mixed plantations The species relationship of the natural forest is a result of many different factors and causes That may be the result of competition for nutrients, light and living space among species This may be the result of phytonites of neighbouring trees In addition, the relationship is also influenced by shape and structre of branches and the trunk of forest species Spatial distribution of species on the ground plays a very important role in the analysis of forest structure Spatial distribution of species is one of determinants for sampling design methods in forest inventory, timber supply capacity from forests, and treated silvicultural measures Spatial distribution of forest trees is often influenced by many ecological processes Thus, it will reflect a degree of competition between trees, density, size distribution, mortality rates, timber volume and carbon absorption capacity in stands (Li, L., et al., 2009) The North Zamari Reserve Forest, is a roughly 75,000 - hectare zone of highly threatened moist upper mixed deciduous forests that contain numerous threatened and endangered species However, there is currently limited research and analysis on JOURNAL OF FORESTRY SCIENCE AND TECHNOLOGY NO - 2018 55 Silviculture relationships among species in this region Especially, up to now there has never been any study analyzing the spatial distribution of species on the groud here Therefore, in order to solve these problems, the paper will: (1) Analyze the relationship between individual species based of individual frequencies; (2) Analyze the relationship between dominant species by distance and (3) Analyze and compare the spatial distribution patterns of forest trees on the ground between some natural forest states by using multivariate analyses to provide a solid basis for sustainable forest resource management in the study area II RESEARCH METHODOLOGY 2.1 Study area and data collection method Data were collected from 15 plots of natural forest at the North Zamari Reserve Forest, Thayarwaddy, Myanmar Each plot has an area of 1000 m2 The study established five plots for each forest type Forest types include: oldgrowth forest, 20 years after logging and 10 years after logging The used sampling method was the stratified random method for selecting the plot positions This is an appropriate method for surveying forest resources, because forest ecosystems are often not homogenous (Hung, B.M and V.D Hai, 2017) In each plot, all trees with diameter greater than cm are measured and their scientific names were identified The species name is determined by the plant experts of the University of Myanmar With unknown species in the field, samples were sent to a laboratory of the University of Myanmar for examination, analysis and identification These data are used for analysis in this article 2.2 Data analysis method All data is analyzed by using R version 3.4.3 Specific contents are as follows 2.2.1 Analysis of relations between species 2.2.1.1 Analysis of dominant species and 56 differences in biodiversity between states This analysis was conducted by correspondence analysis Correspondence analysis was used two variables: species and plot variables This analysis will find the relations between plot and species variable, based on occurrence frequencies of the species From there, it can help scientists identify dominant species for each plot as well as classify plots with similar levels of biodiversity To this analysis, following commands were conducted in R: fit