Research on some main characteristics of natural forest in hoang lien national park lao cai province

MINISTRY OF AGRICULTURE AND RURAL DEVELOPMENT VIETNAM NATIONAL UNIVERSITY OF FORESTRY STUDENT THESIS RESEARCH ON SOME CHARACTERISTICS OF NATURAL FOREST IN HOANG LIEN NATIONAL PARK - L

MINISTRY OF AGRICULTURE AND RURAL DEVELOPMENT

VIETNAM NATIONAL UNIVERSITY OF FORESTRY

STUDENT THESIS

RESEARCH ON SOME CHARACTERISTICS OF NATURAL FOREST IN

HOANG LIEN NATIONAL PARK - LAO CAI PROVINCE

Major: Natural Resources Management

Code: D850101

Faculty: Forest Resources and Environmental Management

Student: Bui Doan Mai Anh Student ID: 1253090001 Class: K57 Natural Resources Management Course: 2012 - 2016

Advanced Education Program Developed in collaboration with Colorado State University, USA

Supervisor: Dr Ha Quang Anh

Ha Noi, Oct 2016

ACKNOWLEDGEMENTS

This report is submitted for the Advanced Education Program Developed in collaboration with Colorado State University, USA, faculty of Forest Resources and Emvironmental Management, Vietnam Natural University of Forestry This study would not have been possible without the kindness help of many individuals and institutions Most importantly, I am very grateful to my supervisor Dr Ha Quang Anh for his guidance, instruction, and encouragement at every step of my study and for sharing his knowledge and ideas with me

I would like to thank Hoang Lien National Park (NP), Science and International Cooperation Department of the NP with many good people who provide documents and go to the field survey with me

ABSTRACT

This study contributed findings of some main characteristics of natural forest in high zone vegetation in Hoang Lien National Park included trees floors, regenerated trees and shrubs, fresh vegetation floors Based on the research objectives, a study decision used fieldwork methods and some document from the publications and files of different agencies combined with calculate by formula of excel software and SPSS to find the result about characteristics of vegetation above 2700m elevations From that, the study will proposed

measures served to forest management; improve efficiency for the protected forests

TABLE OF CONTENT

ACKNOWLEDGEMENTS

ABSTRACT

TABLE OF CONTENT

APPENDIX

LIST OF TABLE

LIST OF FIGURE

ABBREVIATION

CHAPTER 1 INTRODUCTION 1

CHAPTER 2 GOALS, CONTENTS AND STUDY SITES 4

2.1 Goals and specific objectives: 4

2.2 Study sites: 4

CHAPTER 3 METHODS 8

3.1 Collecting data: 8

3.1.1 Secondary data colection: 8

3.1.2 Fieldwork methods: 8

3.3 Classification vegetation system of Hoang Lien NP: 15

CHAPTER 4 RESULTS 17

4.1 Forests structure characteristics of trees stories: 17

4.1.1 Structural composition and density: 17

4.2.2 The distribution rule of forest stand: 20

4.3 Structural characteristics of regeneration stories: 26

4.3.1 Structure composition and density of tree regeneration: 26

4.3.2 Origins regeneration: 27

4.3.3 Density regeneration by qualities: 28

CHAPTER 5 DISCUSTION 30

5.1 Results analyzed field data: 30

5.1.1 Structural composition and density: 30

5.1.2 The distribution rule of forest stand: 31

5.1.3 Structural characteristics of regeneration stories: 32

5.2 Factors affecting the forest vegetation: 34

5.3 Propose some measures to conserve natural resources: 34

5.3.1 Planning for conservation and sustainable development Hoang Lien NP: 34

5.3.2 To raise awareness about natural resource management and forest protection laws: 35

5.3.3 Economic development, increasing income for the community: 35

5.3.4 Strengthen management and protection: 35

5.3.5 Make well the task of forest fire prevention and fighting: 36

5.3.6 Strengthening the scientific research activities and international cooperation: 36

5.3.7 Population Stabilization: 36

5.3.8 Solution silviculture: 36

CHAPTER 6 CONCLUSION 38

REFERENCE 39 APPENDIX

LIST OF TABLE

Table 4.1 Composition and density of the IA2d forest status of San Sa Ho commune 17

Table 4.2 Composition and density of the VB2 forest status of San Sa Ho commune 19

Table 4.3 Modeling results distribution N / D1.3 with theoretical functions 20

Table 4.4: Modeling results distribution N / H with theoretical functions 22

Table 4.5 Correlation equation H/D1.3 by Linear and Logistic functions in IA2d forest status 24

Table 4.6 Correlation equation H/D1.3 by Linear and Logistic functions in VB2 forest status 25

Table 4.7 Composition and density of tree regeneration 26

Table 4.8 Tree regeneration sources 28

Table 4.9 Tree regeneration by qualities 29

LIST OF FIGURE

Picture 2.1 Administration Map of Hoang Lien National Park, Lao Cai Province 5

Figure 4.1 Charts simulated the distribution rule N / D1.3 in IA2d forest status 21

Figure 4.2 Charts simulated the distribution rule N / DBH in VB2 forest status 21

Figure 4.3 Charts simulated the distribution rule N /H in IA2d forest status 23

Figure 4.4 Charts simulated the distribution rule N /H in VB2 forest status 23

Figure 4.5 Correlation equation H/D1.3 in IA2d forest status 25

Figure 4.6 Correlation equation H/D1.3 in VB2 forest status 26

Figure 4.7 Regeneration density by species 27

Figure 4.8 Regeneration density by sources 28

Figure 4.9 Regeneration density by qualities 29

ABBREVIATION NP: National Park

SP: Standard plot

OS: Other species

IV: Important value

DBH or D 1.3 m: Diameter at Breast Height

CHAPTER 1 INTRODUCTION

Forest are valuable resources, there is an important role for the national economy Vietnam’s forests have basic characteristics of tropical forests, with high biological diversity and large biomass

People study and see the forest as an ecosystem that has the characteristics and special structures Forest structure is the internal reorganization of the component organisms in forest ecosystems through which the species has different ecological character can live in harmony and achieve relative stability “Forest structure is not only the result but it also the expression

of relations of struggle and mutual adaptation between forest biological and ecological environment among each other woodland creatures” (Ngo Quang De 1992) In our country, the study of forest structure mostly focused on object are plantation forests and protection forests The study of the structure and regeneration of the special-use forests still less So the solution to conservation of natural resources, biodiversity values in the area of special-use forests lacking scientific basis, not really effective

While, in the world, many researchers had research on natural forest structure

"Features of the structure and natural regeneration have been many scientists around the world conducting research to establish a scientific basis and theoretical work in service of forest business The study of the ecological structure of the rainforest was P W Richards (1952), G N Baur (1964), E P Odum (1971) conducted These studies have raised perspective, the concepts and qualitative description of the composition, life forms and slab floor of the forest "(Luong Thi Thanh Huyen, 2009)

“Some typical projects of authors like Hara et al (1978-1982), Kapos et al (2000), Rainer W Bussmann (2006), JMNinot & A.Ferre (2008) These studies have focused on the distribution of elevations zone on the basis of natural conditions, direction exposed terrain, ” (Truong Ngoc Kiem, 2014)

With Vietnam forest, the complexity show the clearest in the structure of the tree species composition and second stories The study of forest structure not only helps maintain the stability of the forest ecosystem, conditioning the structure factors, but creates an opportunity for managers to use and promote maximum sustainable benefits of forests for the economy, society and environment Therefore, one of the important issues to be studied is to find out the rules of forest structure as a basis for proposing measures appropriate protect and develop forest resources sustainably

In Vietnam, “The adequate studies on the distribution of vegetation by elevation is not much that often only one of the research content of flora.” (Truong Ngoc Kiem, 2014) The essence of the elevation rule with local particular character depends on the foothills zone base with other factors should in each region in the world have different projects related to this rule “Because of Vietnam’s hills differentiate continuously from north to south so territorial differentiation is dominated very clear by elevations rules”(Truong Ngoc Kiem, 2014) Vu Tu Lap (1976) divided into three zones: from 0 - 600m (internal zone foothills monsoon tropics, including the sub zone), from 600 - 2.600m (sub tropical monsoon zone on the mountain, including the sub zone ), Over 2.600m (temperate monsoon zone on the mountain) And, Thai Van Trung (1978) divided the zone: tropical moisture (less than 700m in the north and to 100m in the south), subtropical low mountain downstairs (from 700m - 1600m in the north and from 1000m - 1800m in the south ), warm temperate low mountains upstairs (from 1600m - 2400m in the north and from 1800m - 2600m in the south), cold temperate medium mountains downstairs: over 2400m in the north and 2600m in the south

Hoang Lien National Park (NP) was chosen as a center of diversity of plant species in the conservation program of plant species of International Union for Conservation of Nature (IUCN) National Park is also a global environmental fund is classified as A, the most senior

of the value of biodiversity in Vietnam, and Hoang Lien NP is recognized as ASEAN heritage

park With ecosystem diversity are fauna and endemic, and have higher valuable research and tourism Hoang Lien NP is becoming a great places for tourist and research

However, due to the development of tourism and the exploitation forest products of people, national park is in danger of being abused, primary forest area is about 30%, the rate

of forest degradation in alarming rate partly by further intervention and no plans of man Besides, due to the nature elevation, Hoang Lien NP is the only place in Vietnam with temperate zone monsoon on the mountain (from 2700m)

Stemming from this reality, the topic "Research on some main characteristics of

natural forest in Hoang Lien National Park – Lao Cai Province" were made to contribute

additional information of natural forest structure in Hoang Lien NP At the same time, the research results is expected will be the basis of the proposed measures protection, reforestation and some reasonable impact on forests in the study area in particular, and in similar ecological zones Vietnam in general To ạchieve that goal, this study will answer the following questions: What is the structural characteristics of high zone vegetation of natural forest in Hoang Lien NP? What is distribution rule and correlation between survey factors? What are the factors affecting to the forest structure and biodiversity values? How can protection and development of forests in Hoang Lien NP?

CHAPTER 2 GOALS, CONTENTS AND STUDY SITES 2.1 Goals and specific objectives:

- Goal: Addition knowledge about forest structure of high zone vegetation of natural forest in Hoang Lien NP

59’ The total area of land under the management of Hoang Lien NP is 51.800 ha, including 29.845 ha core zone About the administrative boundaries, its located in 6 communes: San Sa Ho, Lao Chai, Ta Van, Ban Ho, Muong Khoa and Than Thuoc belong to Sapa district in Lao Cai province and Than Uyen district of Lai Chau

Picture 2.1 Administration Map of Hoang Lien National Park, Lao Cai Province

Hoang Lien mountain range is a system of over 2000 m high peaks running from the Northwest - Southeast Especially, in the National Park with high peaks Fansipan 3.143m compared to sea level, be likened to "roof" of Vietnam in particular and Indochina in general Most of the peaks has an average elevation of 2000 - 2500 meters, where the average was the lowest of the Ban Ho Sapa is an elevation is 380m Towards the south of the valley as flat, broader and most ethnic minorities are used as terraces The main types of terrain Hoang Lien

NP consists of high mountains, valleys and hill slopes

In the core area of Hoang Lien NP, there are 04 main ethnic minorities (Mong, Dao, Giay, Tay), scattered population, particularly has 5 villages in the core zone of the park, so the propagation and dissemination awareness education for people is limited and staff were

difficult to travel, exchange exposure, guidance, inspection, monitoring and management of forest protection Mainly business practices of upland peoples is agricultural with rice production forms on the narrow terraces The phenomenon of shifting cultivation, slash and burn agriculture have reduced the forest area quickly Besides, forest fires, hunting of wild animals for food and sold for money (skin, horns), medicinal have caused damage to the forest Along with other activities such as logging, firewood, forest products, pharmaceuticals, it has become a threat to the risk of depletion of biodiversity and deforestation The education, health care and infrastructure system (roads, electricity, water ) are difficult due to rough terrain and population are not living concentrated (Source: Hoang Lien National Park)

Overall, the life of the people is quite poor, labor surplus in unharvested season lead to operate illegal forest exploitation continues, besides some people along the Hoang Lien NP not quit living on forest practices and forest products harvesting, hunting animals These are major challenges for the management and conservation of the park (Source: Hoang Lien National Park)

With locations in the east of the Hoang Lien, complex terrain regional climate regimes Hoang Lien NP is also strongly differentiated according to terrain elevation and direction One characteristic of the Hoang Lien's climate is almost all year round in wet conditions The average relative humidity of about 85%, monthly at least average rainfall well over 20-30

mm The average air temperature in popularity index from 13-21°C, larger in western slopes, smaller in eastern flank The lowest temperature in December and January, many years to less than 5°C In winter every year with frost and snow can sometimes below -3°C Because there are no data on meteorology in areas where higher elevations Sa Pa, but it can be said that the climate gets higher as heat tends to decrease At an altitude of over 3000 meters, according to the data measured by the survey team, the average temperature is 12°C or only lower in the

rainfall between the months of the year, especially during the summer months, the relatively high rainfall The rainy season starts from mid-March to mid-October, two months are July rainfall (454.3 mm) and August (453.8 mm) Humidity air is relatively high, about 86% annual average Biggest humidity month is September and November with a value of 90%, especially in April Dry worth 82% In addition to the general weather factors, there are also special weather phenomena such as fog, frost, drizzle, thunderstorms, frost

The differentiation climate of Hoang Lien National Park very complicated, it is characterized by many special elements, as well as the nature of the tropical, subtropical and

temperate According to the research subjects " Assessment survey combined flora and

mammal surveys in the Hoang Lien National Park - Lao Cai Province", vegetation

overlay’s Hoang Lien National Park is classified under 3 main zones: Lower zones (<700m)

is classified as the Tropical monsoon while Middle zones (700m - 2,700m) is classified as Subtropical monsoon on the mountain The remaining zone is greater than 2700m where is known as Temperate monsoon zone on the mountain

In this study, natural forest on Temprate monsoon zone (>2700m) was considered as

my object of interest

CHAPTER 3 METHODS 3.1 Collecting data:

3.1.1 Secondary data colection:

Secondary documents such previous relevant publications and reports were reviewed

in order to get an overview of my study interest in my study site

Before going to the field, I reviewed documents (secondary data) from the publications and files of different agencies, such as Vietnam National University of Forestry, Hoang Lien National Park, some websites to get better understanding about the site study, the characteristics of local people and the content of what I was going to do I found key themes that have been explore and took note to compare with reality

3.1.2 Fieldwork methods:

* Prepare tools and materials:

Before conducting fieldwork, should prepare some instruments and documents relating follows: Measuring tape 30m, GPS, handheld locality, glass calipers, Blumeleiss, balance springs, nylon bag, canvas bags, paint, tables and other documents

* Collecting field data:

Based on topographic maps of the park, proceed to determine the boundaries altitudes above 2700m follow contours, route surveys and survey sample plots established on the typical plant communities To study the full range of vegetation zones represent researching, selecting research route, study sites are very important Based on topographic maps and maps

of forest resources of the Hoang Lien National Park, conducted online survey route On that basis, the project has identified 1 route surveys: Xe Mountain - Fansipan route: This is the tourist route conquer Fansipan located in San Sa Ho Commune, Sapa district, has a length of 11.2 km, the route starts from the Tram Ton (1900m) up to the top end is Fansiphang (3.143m) This is the most typical representative route for the transformation of plants

according elevations, route have been hit hard by human travel activities, research projects set the standard plot on remote locations line trail, where most little affected by humans

(40m*25m) Each standard plot must specify the following information: location, forest conditions, the process of measuring

In standard plots, investigating the following criteria:

+Note the data in table 1: trees stories survey:

- In regenerated trees stories:

+ Investigation regenerated trees: Each plot set 5 sub-plots: Four sub-plots at the four corners of the standard plot and one sub-plot in the middle with an area of 5m * 5m In sub-plot investigate under 6cm diameter trees with the following criteria: species name, height, quality and origin of each tree regeneration

+ Quality of each species was assessed on three level:

B - Medium Between two types above

+ Note the data in table 2: regenerated trees stories survey

Number of

sub-plot

No (Species)

Species

Hight of trees ( cm )

Source of reproduction

Composition ratio of each species (Standard plot) calculated according to the method

of Daniel Mamillod, Vu Dinh Hue (1984), Dao Cong Khanh (1996) through two indicators: Ratio% density (N%) and basal area (G%) Each species is determined composition ratio IV% (Important Value Index):

Where :

- N% is the relative abundance of species (i): calculated by taking the number of individuals

of species (i) divided by the total number of individuals of all species then multiplied by 100%

- G% is the relative advantage of species (i): calculated by taking the total cross-sectional body area at a height of 1.3 m of the tree species (i) divided by the total cross-sectional body area at a height of 1.3 m of all trees were investigated and then multiplied by 100%

Determination composition ratio of high story according to the formula:

A = Where:

- A: composition ratio of high story

- m: number of individuals of each species in the SP

- n: the total number of trees in the SP

* Method simulation of the distribution law:

- Distribution distance:

Distribution distance is the probability distribution of the random variable intermittent mathematical form:

In which γ and α are two parameters Curves have distribution of distance as a peak to the

empirical is top form as a shaped J Participate the distribution of distances are estimated as follows:

- n is the total number of trees of all sizes When 1 - γ = α, the distribution of the

If Di is the median diameter, Dmin is the smallest diameter, k is group distance, then xi is defined as follows:

- Distribution decreased Meyer type equations of the form:

Where Y is the observed frequency, X means the quantity of observations, α and β are two parameters In forestry, this distribution is often used to simulate the distribution of plants or species (variable Y) according to diameter (variable X)

* Check the distribution law hypothesis standards of Pearson:

standards based on a comparison between the frequency reasoning calculated according distributions theory and experimental frequencies corresponding to each groups of the

distribution reasoning calculated according the organization theory in groups ≥ 5, then the random variable:

need to determined and k = m - r - 1, if there is r parameters need to estimate through observation of the sample results

empirical distribution consistent with the theoretical distribution and vice versa

* Research method correlation relationship between factors of forest investigation:

simulation correlation between height and diameter the scientists has used a lot of mathematical equations form to simulate this rule, but with every tree that grows in different conditions, it forms various mathematical equations Thus when studying the relationship between tree height with a diameter at breast height, the subject test with equation form:

* Testing the hypothesis of distribution law:

defined To test the hypothesis H0, people use appropriate standards when the square of the Pearson:

Where: ft is the experimental values

flt is the theoretical values

the theory distribution need to estimate, m is the number groups after gross), the theory of

To facilitate the process of calculating and graphing distribution theory with experiment, analyze the relationship H / D Topics using Excel software and analyzed by SPSS

b For regeneration stories:

* Organization of regeneration: The regeneration of plants is determined by the ratio between the number of a certain species compared to the total number of species of plants in plot Composition was calculated using the formula:

Where: - Ki is coefficient of the species composition (i)

- Ni number of individuals species (i)

- N the total number of individual investigations

* Density of regeneration:

Regeneration density is determined by the formula:

* Distribution of regeneration according to the height and level of quality

Statistics of regeneration according to 4-level height: <0.5m; 0.5-1m; 1-2m and over 2m Drawing chart represents the number of plants regenerated by level height

* The quality of regeneration

determine the rate of regeneration plants promising to evaluate a general situation of the regeneration taking place in the study area

Proportion of good crops, medium, bad is calculated using the formula:

Where: - N% is the percentage of the tree good, medium or bad

- N total regeneration

- Identify the potential regeneration: the trees with a height greater than the average height of the shrub and good quality, medium

n: is number of trees

3.3 Classification vegetation system of Hoang Lien NP:

Forest classification is a very important and considered as the very fundamental steps for doing forest management Hoang Lien National Park’s vegetation was classified into different classes based on its characteristics following UNESCO’s system (1973) and Phan

Ke Loc (1985) These classification systems were presented as the following:

I Closed forest formation layer

IA Mainly evergreen forest

IA2 Formation group of evergreen rainforest monsoon

IA2b Formations evergreen rainforest monsoon in the low mountain

IA2c Formations evergreen rainforest monsoon in the medium mountain

IA2d Formations evergreen rainforest relative humidity in the high mountain (access Alpin) IA2e Formations tropical bamboo forests in lowland and low mountains

II Light forest formation layer

III Shrub formations class

IIIA Shrub mainly evergreen formations subclass

V Grasslands formations class

VA Grasslands high paddy forms formations subclass

VA3 Tropical grasslands high paddy forms with shrubs and woodtrees

VB5 Tropical grasslands high paddy forms without woodtrees

VB Medium grasslands paddy forms class

VB2 Medium tropical grasslands paddy form with tree cover less than 10%, with or without shrubs

VB3 Medium tropical grasslands paddy form with shrubs without woodtree

VC Low grasslands class

VD.Grasslands class without paddy form

In the thesis, I had been survey 3 SP at 3 areas which are represent for 3 status, there are:

+) IA2d Formations evergreen rainforest relative humidity in the high mountain (access Alpin)

+) VB2 Medium tropical grasslands paddy form with tree cover less than 10%, with

or without shrubs

+) VB3 Medium tropical grasslands paddy form with shrubs without woodtree

CHAPTER 4 RESULTS 4.1 Forests structure characteristics of trees stories:

4.1.1 Structural composition and density:

4.1.1a IA2d forest status:

Forest type in the region and reach the top of Fansipan peak, can be considered as

dominant forest Rhododendron and Tsuga dumosa Rhododendron species grows almost pure

layer), look remotely like the dark blue hat located on the lawn The other broad-leaved trees

are common here: Viburnum cordifolium, Eriobotrya, Illicium, Symplocos, Rhodoleia

DBH average (cm)

Table 4.1 shows that: this forest type appear 8 timber species, 4 species involved in the

constitution of the following formula: (A1) = 47.0Rho + 23.9Tsu + 12.2 Vib + 8.6 Lith +

8.3Other species (OS - 4 species)

Where: Rho is Rhododendron, Tsu is Tsuga dumosa, Vib is Viburnum cordifolium,

Lith is Lithocarpus phansipanensis A Camus

The total important level of participating species composition formula is 88.0% Tree

species composition mainly large timber species: Rhododendron, Tsuga dumosa The average forest density reaches 510trees/ha Rhododendron which has the largest density reached 240trees/ha with 47.1% of total species, important level indicators equal 47.0% Tsuga

dumosa which has the density reached 110trees/ha with 21.6% of total species, important

level indicators equal 23.9% Although the average tree density is low but the number of species with DBH index bigger than 30cm pretty much (DBH average index of 3 of 4 main species from 31.5 to 36.1cm)

So in this forest status mainly medium and large trees, the average of the lower species composition is 8 timber species/ha, an average diameter 26,3cm, average height 8.2m, Total

4.1.1b VB2 forest status:

This form of distribution in the mountainside of the vicinity peak, mostly species of

the average grasslands paddy forms are Sinarundinaria petelotii, Bashania fansipanensis,

Borinda fansipanensis, Cyperaceae belong to Carex genus, they predominate in the

population with high coverage, sometimes close to 100%.The growing tree species

intermingled but cover less than 10%, which are the species of Ericaceae, Illiciaceae,

Symplocaceae, some shrub presence belongs to Ericaceae, Lauraceae, Rosaceae, Berberidaceae

From the survey data 2 SP, I conducted gross the average SP, the species composition results are summarized in the table below:

Table 4.2 Composition and density of the VB2 forest status of San Sa Ho commune

(Tree/ha)

DBH average (cm)

H average (m)

The above table shows that in this forest type appears 23 timber species and there are

5 species involved in the composition of the following formula: (A2) = 20.8Rho +

18.8Rho.nii + 10.6Lit + 6.8Myr + 10.1Tsu + 32.9OS (18 species)

Where: Rho is Rhododendron, Rho.nii is Rhodoleia championii, Lit is Litsea cubeba,

Myr is Myrsine semiserrata, Tsu is Tsuga dumosa, OS is other species

The total important level of the mainly species is 67.1% Tree species composition

mainly small trees such as: Rhododendron, Rhodoleia championii, Litsea cubeba The average forest density reaches 580trees/ha Rhododendron which has the largest density

reached 95trees/ha with 22.4% of total species, important level indicators equal 20.8% Species composition mainly small trees with an average diameter 9.8cm, average height 4.7m,

4.1.1c VB3 forest status:

This is a form which characterize the peak at elevations over 2900m (around the top of

fansipanensis are the largest dominant (100%) The shrub grows alternately, rising out of the

grass mostly is Ericaceae, such as: Rhododendron spp, Gaultheria spp, Vaccinium spp,

Pieris formosana, There is also some other representatives belong to Gentianaceae, Gesneriaceae, carex sp

Through investigation 2SP does not detect any trees so the subjects are not evaluate species composition and composition formulas

4.2.2 The distribution rule of forest stand:

4.2.2.1 The distribution rule of trees in diameter (N / D 1.3 ):

Distribution of trees in diameter is considered one of the important manifestations of structural rules forest stand

The results of modeling the distribution of trees in diameter by 3 functions: Weibull, distance and Meyer are summarized in the table below:

Table 4.3 Modeling results distribution N / D1.3 with theoretical functions

Che-ck

-+ IA2d forest status:

Figure 4.1 Charts simulated the distribution rule N / D1.3 in IA2d forest status

accept hypothesis Ho or Weibull distribution consistent with empirical distributions Specific parameters are accepted with α= 2.5, λ = 0.001756, frequency focused in diameter 12.5cm -

function and distance functions are not suitable to distribution of empirical

+ VB2 forest status:

Figure 4.2 Charts simulated the distribution rule N / DBH in VB2 forest status

Weibull distribution functions has 9.487729 mean Ho+, accept hypothesis Ho or Weibull distribution consistent with empirical distributions Specific parameters are accepted with α= 2.5, λ = 0.012608, frequency focused in diameter 9.5cm -

function and distance functions are not suitable to distribution of empirical

4.1.2.2 The distribution rule of trees in tree height (N / H):

Distributions N / H is one of the basic rules reflect the relationship of the second stories and adaptation extent of forest trees For natural forest which has more canopy, this structure very complex

The results of modeling the distribution of trees in diameter by 3 functions: Weibull, distance and Meyer are summarized in the table below:

Table 4.4: Modeling results distribution N / H with theoretical functions

-+ IA2d forest status:

Figure 4.3 Charts simulated the distribution rule N /H in IA2d forest status

accept hypothesis Ho or Weibull distribution consistent with empirical distributions Specific parameters are accepted with α= 2.5, λ = 0.010987, frequency focused in heigh 9.5cm - 13.5

function and distance functions are not suitable to distribution of empirical

+ VB2 forest status:

Figure 4.4 Charts simulated the distribution rule N /H in VB2 forest status