Evaluate the growth capacity of some indigenous tree afforestation models at the center of environmental research in hoa binh province

MINISTRY OF AGRICULTURE AND RURAL DEVELOPMENT VIETNAM NATIONAL UNIVERSITY OF FORESTRY STUDENT THESIS EVALUATE THE GROWTH CAPACITY OF SOME INDIGENOUS TREE AFFORESTATION MODELS AT THE CENT

MINISTRY OF AGRICULTURE AND RURAL DEVELOPMENT VIETNAM NATIONAL UNIVERSITY OF FORESTRY

STUDENT THESIS

EVALUATE THE GROWTH CAPACITY OF SOME INDIGENOUS TREE AFFORESTATION MODELS AT THE CENTER OF ENVIRONMENTAL RESEARCH IN HOA BINH PROVINCE

Major : Natural Resources Management Code : D850101

Faculty : Forest Resources and Environmental Management

Student ID : 1453091252

Advanced Education Program Developed in collaboration with

Colorado State University, USA

Supervisor: Dr Ha Quang Anh

Hanoi, October, 2018

ACKNOWLEDGEMENT

To accomplish and complete this thesis, I have received a great deal of support from organizations and individuals First of all, I would like to send my sincere thanks to the School Management Board, teachers in the Forest Resource and Environmental Management Faculty for helping me with my studies and training at the school

In particular, I would like to express my deep gratitude to Dr Ha Quang Anh for his great guidance in the process of implementing this thesis

Besides, this thesis could not be completed without help of the officers, especially Mr Tran Trung Thanh – director of the Center of Environmental Research Hoa Binh city who helped me in the process of surveying, collecting data and assessing the afforestation situation

at the research center

Finally, I would like to send my most sincere thanks to my family, relatives and friends who have encouraged and helped me through the process of completing this thesis

Although there have been a range of attempts to complete the project, due to the limited time and knowledge, the thesis is inevitable shortcomings So, I hope that I could receive the attention and comments of teachers and friends to complete the course

Hanoi, September 1, 2018

Student

Dao Duy Duc

TABLE OF CONTENTS

ACKNOWLEDGEMENT i

TABLE OF CONTENTS ii

ABSTRACT vii

CHAPTER 1 GENERAL REVIEW OF THE RESEARCH ISSUE 1

I Introduction 1

II GENERAL REVIEW OF THE RESEARCH ISSUE 3

2.1 In the world 3

2.1.1 Indigenous plants in the world 3

2.1.2 Basis researches 3

2.2 In Vietnam 4

2.2.1 Indigenous plants in Vietnam 4

2.2.2 Basis researches 5

2.2.3 Practical researches 5

CHAPTER 2 OBJECTIVES, CONTENTS, RESEARCH SUBJECT, LIMITS AND RESEARCH METHODS 7

2.1 Objective 7

2.2 Contents 7

2.3 Research subject 7

2.4 Limits 7

2.4.1 Place 7

2.4.2 Time 8

2.5 Materials and methods 8

2.5.1 Materials 8

2.5.2 Methods 13

CHAPTER 3 NATURAL, SOCIO-ECONOMIC CONDITIONS OF RESEARCH

AREA 18

3.1 Natural conditions 19

3.1.1 Geographical location 19

3.1.2 Topographic 19

3.1.3 Climate 20

3.1.4 Hydrological 20

3.1.5 Geology, soil 21

3.1.6 Forest resources 21

3.2 Social and economic conditions 22

3.2.1 Population, ethnicity and labor 22

3.2.2 Infrastructure 23

CHAPTER 4 RESULTS AND DISCUSSION 24

4.1 Growth criteria 24

4.1.1 Height growth (H vn ) 24

4.1.2 Diameter at breast height – DBH (D 1.3 ) 27

4.1.3 Canopy diameter (D t ) 30

4.2 Trees’ quality 32

4.3 Survival rate 36

4.4 Vegetation cover and shrubs 37

4.4.1 Vegetation cover and shrubs in Acacia mangium model 38

4.4.2 Vegetation cover and shrubs in Acacia auriculiformis model 39

CHAPTER 5 CONCLUSION, DRAWBACKS AND PROPOSAL 41

5.1 Conclusion 41

5.1.2 Trees’ quality 42

5.1.3 Survival rate 42

5.1.4 Vegetation cover and shrubs 43

5.2 Drawbacks 43

5.3 Proposal 43

REFERENCES

APPENDIX

LIST OF TABLE

Table 4.1: Average height growth of the investigated species 24

Table 4.2: Diameter at breast height growth – DBH of the investigated species 27

Table 4.3: Canopy diameter growth of the investigated species 30

Table 4.4: Trees quality in different time period 32

Table 4.5: Average quality of each species in all period 33

Table 4.6: The survival rate of tree species by age 36

Table 4.7: Vegetation cover and shrubs in Acacia mangium model 38

Table 4.8: Vegetation cover and shrubs in Acacia auriculiformis model 39

LIST OF FIGURES

Figure 2.1: Overview of the project approaching method 14

Figure 4.1: Average height (Hvn) among different species 25

Figure 4.2: Annual height increase (Hvn) among different species 26

Figure 4.3: Erythrophleum fordii 26

Figure 4.4: Peltophorum pterocarpum 26

Figure 4.5: Diameter at breast height (∆D1.3) among different species 28

Figure 4.6: Annual DBH (D1.3) increase among different species 29

Figure 4.7: Cinnamomum obtusifolium 29

Figure 4.8: Lithocarpus ducampii 29

Figure 4.9: Canopy diameter (Dt) among different species 31

Figure 4.10: Annual canopy diameter increase (∆Dt) among diferent species 32

Figure 4.11: Quality of each species in different periods 35

Figure 4.12: Quality of each species in all periods 35

Figure 4.13: Survival rate of species at 1-year and 6-years of age in Acacia mangium model 37 Figure 4.14: Forest vegetation and shrubs 40

it is known that the great benefits that indigenous tree species provide are not merely the provision of specialty forestry products, but also the long-standing evolution of plants should

be highly adaptable to the growing conditions and have high sustainability, therefore, planting

them would have many benefits For that reason, I undertake this research: “Evaluate the growth capacity of some indigenous tree afforestation models at the center of the environmental research in Hoa Binh province” The research was conducted by examining

the area which indigenous trees are planted at the center After preliminary evaluation, two standard sample plots of 500 m2 were established on two different supporting species which are Acacia mangium and Acacia auriculiformis The results illustrate that 5 species in two models grow well under the assistance of supporting plants However, most of the trees Acacia mangium model were better than that of Acacia auriculiformis in terms of diameter growth at breast height (D1.3), height growth (Hvn), canopy diameter (Dt), quality and survival rate After investigating and analyzing the data, some conclusions have been drawn and hopefully they could be used to contribute to the elaboration of the scientific foundations, which shall serve as a basis for proposing solutions for optimizing indigenous trees planting efficiency

CHAPTER 1 GENERAL REVIEW OF THE RESEARCH ISSUE

I Introduction

Forest is a precious resource with multiple benefits for community and society Forest

is an irreplaceable part of the ecosystem which plays an extremely vital role in human life At present, the government restricts the exploitation of natural forests and many regions have shifted to forest plantation Provinces and enterprises determine the purpose of speeding up the economic afforestation in terms of volume and quantity to meet the demand of goods for society, first of all supplying raw materials for industrial parks and houses machine,

Apart from providing timber, firewood and other forest products, forests play a crucial role in protecting and maintaining habitats such as regulating climate, regulating water resources, limiting erosion, mitigating the effects of floods, the absorption of carbon dioxide, the maintenance and conservation of biodiversity

Indigenous plants have formed symbiotic relationships with native wildlife over thousands of years, therefore offered the most sustainable habitat for wild animals A species

is considered as indigenous if it exists naturally in a particular region, ecosystem, or habitat without human intervention

It is challenging for some indigenous plants to adapt to the environment such as harsh climates or special soil conditions Although those plants only exist within a very limited range (endemism), others can live in diverse areas or by adaptation to different surroundings Research has found that insects depend on indigenous plants

An alternative but potentially conflicting usage is to describe plants (and animals) that are indigenous to a geographical area, even if they are known to have self-introduced in historical times

Indigenous plants help the environment the most when planted in places that match their growing requirements They could thrive in the soils, moisture and weather of your region That means less supplemental watering, which can be wasteful, and pest problems that require toxic chemicals Indigenous plants also assist in managing rain water runoff and maintain healthy soil as their root systems are deep and keep soil from being compacted

If planting indigenous species (over 10-years production cycle) instead of other timber trees such as acacia hybrid, the time for the product longer but the value will be larger It is possible to compare the three acacia crops that will take between 23 and 25 years In the meantime, if we invest in the planting of indigenous timber species in Group 3 (common wood for home furniture) Teak, mucilage, hymenoptera , the trees have a diameter of about

20 - 25cm and can be harvested with a stock equal to or greater than the acacia hybrids of 7-8 years old In addition, if the planting of multi-species trees such as pine, black, white fill , the producer will harvest from non-timber forest products for example resin It is higher than that of timber in terms of benefit

Thus, in terms of economic growth of large trees, indigenous trees are at least twice as good as acacia hybrid In terms of the area of afforestation of indigenous trees throughout 25 years, the land is continuously covered by vegetation cover and forest canopy; the forest ecosystem is stable; Acacia hybrid plantation forest is interrupted by two mining operations, equivalent to 5-6 years of land without sufficient cover, which not only eroded soil but also affected climate change

II GENERAL REVIEW OF THE RESEARCH ISSUE

2.1 In the world

2.1.1 Indigenous plants in the world

Indigenous plants are planted to a certain area during geological time This includes plants that have developed, naturally occur, or persisted for many years in an area (plants, flowers, grass and other plants)

Some countries are given good farming conditions, and with it, a number of fruitful trees, while others are less fortunate For example, Peru has over 25,000 native plant species The country has a wide variety of climates and terrains, ranging from coastal lowlands to the Amazon rainforest or the Andes Mountains In the 15th century, the Inca planted over 70 different crops and used a complex of terraces and canals to irrigate saplings

In contrast, a small island nation of the United Kingdom has a barren native vegetation Even the trees planted here at the end of the Ice Age still taste unpleasant A list of wild vegetables, fruits and nuts is available for hunting British hunters including chestnut, blueberry and plum

2.1.2 Basis researches

E.P.ODUM has many research studies on ecology as the basis for researching forest ecosystems This is a very important theoretical basis for the research and development of silvicultural techniques for tropical forest in the world

Geoge N Baur (1952, 1964, 1976) has made extensive ecological studies in the forest business, restoration and management of tropical forests The author summarizes silvicultural treatments to bring the same age and unequal forests to tropical forest business in different continents of the world

Richards PW (1952), Cantinot (1965) explored the morphology of the forest structure

by describing structural elements that are described in detail, living, slate, stratum

Parde (1961), bottam (1972), Rollet (1979) applied statistical mathematics to study the structure of forest growth, quantify the rules and at the same time to propose forest measures development techniques

2.1.3 Practical researches

The study of the application of techniques for regeneration of indigenous tree species

by different planting methods, adding to poor forests, poorly regenerated forests, etc., to improve the quality and quantity has been used in many countries such as Nigeria, Congo, Cameroon, Gabon,

In Japan: Kasama Forest Technology Center has established a series of multi-tiered forest models comprising many different species of forest trees and at different ages, at different heights in the Tsucuba region (876m high with sea squirts) for both the Japanese Cedar tree species and the interactions between plant species as well as the environmental impact of each species has found

In Taiwan and some Asian countries have developed indigenous plants grown in bare hills after being planted with coniferous trees, resulting in sustainable mixed forest models with high productivity and positive effect in protecting the natural environment of the forest and preventing soil erosion

2.2 In Vietnam

2.2.1 Indigenous plants in Vietnam

Since the 1970s, our nation has spent more than 40 years researching and using indigenous trees for afforestation and forestry development throughout the country We have obtained valuable results including preliminary selection of nearly 100 plant species, including 30 internal species, initially meeting the objectives of afforestation and protection forest plantation (Decision No 680/1986 of the Ministry of Forestry)

Subsequently, 50-52 indigenous plant species were selected for plantation forest

16/2005 of the Ministry of Agriculture and Rural Development) 28 species have been studied relatively systematically and 50 species have been put into production on different scales Nearly 22 species of wood are planted on hundreds to thousands of hectares

However, according to a World Bank report in 2005, nearly 700 species of globally threatened plant and animal species in Vietnam are "extremely critical"

The report also points out that the introduction of new plant varieties, especially yielding hybrids, has reduced both the area and genetic resources of indigenous plant varieties More than 80% of indigenous plant varieties are lost in the field after the modernization movement

Nguyen Van Truong (1983), Phung Ngoc Lan (1986) and Vu Tien Hinh (1987,1988) studied and found the results to be based on the model of forest with stable yields (on some key factors)

 On the classification of forest status: there are works by Tran Ngu Phuong (1963), Thai Van Trung (1978), Vu Biet Linh (1984), and many important achievements forest development

 On ecology: The works of Thai Van Trung (1948) on the characteristics of mangrove formation in Ca Mau, vegetation cover on the hills in midland mountainous north (1959)

2.2.3 Practical researches

Tran Nguyen Giang (1961-1963 and 1960-1962), Tran Xuan Tiep - Le Xuan Tam (1963-1967), introduced technical measures for planting and restoration of indigenous trees in order to be effective in the process of high-altitude tree regeneration In these studies, Tran Nguyen Giang has successfully built a model of planting many native species under the trees and has a preliminary report on the growth of forest in the study area However, there is no assessment of the impact of ecological factors as well as the interrelationships between these species

In 1996, Tran Nguyen Giang was studying how to plant 10 indigenous species under canopy of acacia auriculiformis and acacia mangium at Cat Ba National Park The author argues that these two species have the effect of improving the protection of forest soil, supporting the native plant growing and developing should demonstrate how to do so is true But in 1998, the results were not as expected initially, indigenous trees planted under canopy

of acacia auriculiformis have very high survival rate, growth and development quite well, while native plants under the canopy of acacia mangium has a relatively low survival rate, growth and poor development The author explains that this may be due to the large demand for mango juice that makes the soil always dry, thus improving the soil environment

The Northeast Forestry Science and Technology Center (Ngoc Thanh - Phuc Yen - Vinh Yen) has experimented with indigenous plants under the canopy of acacia mangium in

2000 and 2001 on an area of 10 ha in Lung Dong Danh including 5 species indigenous species: erythrophleum fordii, peltophorum pterocarpum, ormosia pinnata, re huong and de Yen The In addition, the center also built some plantation sectors of over 180 species of indigenous plants together with acacia auriculiformis and acacia auriculiformis (1996 - 2001)

CHAPTER 2 OBJECTIVES, CONTENTS, RESEARCH SUBJECT, LIMITS AND RESEARCH

METHODS 2.1 Objective

Evaluating the growth capacity of some indigenous tree afforestation models to contribute to the elaboration of the scientific foundations, which shall serve as a basis for proposing solutions for optimizing indigenous trees afforestation efficiency

2.2 Contents

2.2.1 Comparing some growth criteria among different indigenous trees planting

models (H vn , D 1.3 , D t )

2.2.2 Comparing trees’ quality among different planting models

2.2.3 Calculating survival rate of indigenous trees in Acacia mangium model

2.2.4 Investigating vegetation cover, shrubs

2.4.2 Time

Owing to the limited time and resources, the research only focus on some of the most promising native species which grown on both standard plots (5/10 species in the acacia mangium model and 5/180 species in the acacia auriculiformis model)

In this project, the investigation could not be performed on the whole area but only on some sample plots representing the stands (each plot corresponds to a unit of experimental layout)

This research identifies the relationship between the growth of indigenous plants and a number of contextual factors such as light and vegetation among many factors that dominate the growth of trees

2.5 Materials and methods

2.5.1 Materials

2.5.1.1 Brief introduction of indigenous species planted at the research center

At the research center, there are two models of native tree species under the forest canopy of Acacia species and these are also two models of research subject of the project

1 Indigenous tree species with Acacia mangium model

 In this model, there are 10 indigenous tree species which have high economic value and capable to adapt to the conditions in the selected area by inheriting indigenous knowledge and native materials published

 However, when preliminary survey, it can only be only seen the following species: Ormosia pinnata (ràng ràng xanh), Cinnamomum iners (re hương), Erythrophleum fordii (lim xanh), Lithocarpus ducampii (dẻ đỏ), Peltophorum pterocarpum (lim xẹt), Cinnamomum camphora (long não), Hopea odorata (sao đen) and Cinnamomum obtusifolium (re gừng) In particular, the frequency of encountering Peltophorum pterocarpum, Michelia tonkinensis,

Cinnamomum camphora are very sparse, so the investigation will be performed on the growth

of 5 species

2 Indigenous tree species with Acacia auriculiformis model

 This model was designed to study the adaptation of many indigenous tree species under the site conditions and also to create a valuable botanical garden for scientific research Therefore, the number of species planted in the center is quite large, including 180 species of

45 plant families

 Owing to the total number of species in the area is tremendous, hence, only a number of the most promising species have been selected to carry out a detail survey of the topic covered

 The model of the trees under the canopy of acacia auriculiformis: there are 180 indigenous species of 45 families were planted in the research center However, according to the preliminary survey report of the forest technical department, a number of the best grown species have been selected In order to ensure the suitability of the subject matter, 5 species were selected in the list to investigate the growth capacity

2.5.1.2 The sketchy description about morphology and ecology of indigenous

species which are investigated

1 Erythrophleum fordii (Lim xanh)

- Morphological characteristics: Erythrophloeum fordii is a large, evergreen tree species which is capable of reaching a height of 37–45 m and a diameter of 200–250

cm The stem is rounded with dark brown bark, which is square cracking, has many conspicuous lenticels and can be peeled off in scales The base of the stem has a small buttress The foliage is thick and green all year round The leaves are bipinnate and ovoid, with a rounded base and pointed tip Their upper layer is dark green, whereas the lower layer is pale green with conspicuous veins The inflorescence is apical

racemose and 20–30 cm long with small, white flowers which open in March– April The fruit is an oblong-elliptic pod, 15–30 cm long, which contains 6–12 seeds Fruits ripen in December–January and are brown or greyish black The seeds are large, flat and square-shaped with a pointed tip, and grow at an obtuse angle The seed coat is hard and black (JICA 1996)

- Ecological characteristics: Erythrophloeum fordii grows in many kinds of soil, and can develop in various types of mother soil such as sandstone, shale, mica schist and even soil with a mechanical composition ranging from light to heavy It can tolerate high humidity, an average to high acidic content, and site conditions which have a humid and deep soil layer It usually grows with many other broad leaved tree species

in a multistoreyed forest environment, where vegetation is rich (FSIV and JICA 2003)

- The tree grows slow, the growth rate depends on age and distribution Flowering season from March to May, fruit ripen in October to November Light-loving plants, when small live under the canopy The average ideal temperature for developement is 22.4 – 24.100C and average ideal rainfall is 1500 – 2859 mm The ability to regenerate seeds is good

2 Peltophorum pterocarpum (Lim xẹt)

- Peltophorum pterocarpum is a large tree species, 25 – 30 m in height, diameter (DBH) could reach to 50 – 60 cm Light brown skin, with many lines around the body

Straight stem, small root Branches have rusty feathers

- Double feather, dark green, with 7 – 16 pairs of secondary petiole Each petiole has 5 – 15 pairs of oval-shaped leaves that are 1 cm length, 4 – 9 mm width Young rusty leaves, early fall

- In the natural forest, Peltophorum pterocarpum flowers start at the age of 7 – 8

Flowering from April to May, fruit is in flat bean shape When the fruit is ripe, the fruit skin is dark brown, the fruit is sticky to its stem

- Morphological characteristics: It is a deciduous tree growing to 15–25 m (sometimes

up to 50 m) tall, with a trunk diameter of up to 1 m belonging to Family Leguminosae and sub-family Caesalpiniaceaea The leaves are bipinnate, 30–60 cm long, with 16-20 pinnae, each pinna with 20-40 oval leaflets 8–25 mm long and 4–10 mm broad The flowers are yellow, 2.5–4 cm diameter, produced in large compound raceme up to 20

cm long The fruit is a pod 5–10 cm long and 2.5 cm broad, red at first, ripening black, and containing one to four seeds Trees begin to flower after about four years

3 Lithocarpus ducampii (dẻ đỏ)

- A mature Lithocarpus ducampii is large tree species with approximately 50 – 60 cm in diameter (DBH), up to 30m in height, with straight trunk; gray-brown casing, deep cracks Usually has wide canopy and green all year round

- Single leaf, early fall; mostly in spike shape which is about 10 – 12 cm in length, 3 – 4

cm in width, petiole 1 cm long; Leafy veins are prominent on the underside, the top of the leave is star-shaped rust

- Unisexual flowers Male flowers have 10 – 12 stamens which is long and slender Female flowers grow into cluster, each cluster has 2 to 5 flowers The flower season in from May to July Fruits do not have stem, grow into clusters of 3, with many sharp spikes, fruit is 1.5 – 2 cm in height, diameter is 1 – 1.5 cm Fruit season from

November to December

- Lithocarpus ducampii is suitable for growing with tropical monsoon climate while the average rainfall of 1500 – 2500 mm/year and the average temperature of 22 – 270C

- Reproductive capacity of seed under canopy condition is good Light-loving plants, requires lightly shade to grow in the early years Business cycle is not too long (25 –

35 years) because Lithocarpus ducampii grows relatively fast Lithocarpus ducampii can be used for pure plantation, afforestation, enrichment and rehabilitation

4 Cinnamomum obtusifolium (re gừng)

- Cinnamomum obtusifolium is a large tree species which could reach up to 30 m in height, diameter (DBH) can reach 50 cm Brown or dark brown, smooth, shiny brown

or light yellow, crisp and fragrant Young green shoots, when old brown

- Single leaf, grows upright or opposite, spike or oval, smooth which could reach 9 – 30

cm in length, 3.5 – 9 cm width The stem is 12-20mm long

- Bisexual flowers have two forms: middle flowers are larger than the flowers Each flower has 6 pieces, oblong, hairy on both sides Males reproduce 9, 3 times, 2

degenerate, 4 pollen Flower pot is in egg-shaped, smooth, long tap with gourd

Flower season in March

- The fruit is in egg-shaped, 1 cm in length The fruit is green at first, at nine stage, the fruit turns dark green, flesh is light purple color with a light brown seed, could be harvest in February to March

5 Hopea odorata (Sao đen)

- Hopea odorata is a large tree species, mature species could reach 30 – 40 m in height, straight cylindrical shape, diameter (DBH) up to 60 – 80 cm Small pruning, good pruning of branches so the branches under the branches long and straight Black-brown shell, longitudinal crevice Young shoots and hairy petioles

- Single leaf in spear shape, is 9 – 11 cm length, the veins are clear Leaf replacement in the dry season but does not fall simultaneously as other trees

- Flowers are clustered with 11-12 small branches, each cluster has 4-6 flowers, hatched

in February to March Fruits with two wings with 5 – 6 cm in length, ripen in April to May One kilogram of grain has about 3000 seeds

- Hopea odorata is well-grown and well-developed in tropical climate where rainy and dry seasons distinct with an average temperature of 24 – 250C and annual rainfall of

1800 – 2000 mm/year

2.5.2 Methods

In forest trees’ life, the forests themselves are affected by environmental factors around them The sub-forest situation includes the sub-climate of the forest and forest land It can

be seen that the present status of the indigenous plant layer reflects the resultant interaction

of the ecological environment where they grow

Therefore:

 When studying the growth of indigenous tree species, it requires the overall impact

of high tree layer and other factors This means the status of supportive trees and other factors ecology have to be assessed

 When assessing the relationship between the biomass and quality of indigenous tree layers with supportive tree layers and other ecological factors, it is necessary to assume that the remaining factors are homogeneous and that the variation in this heterogeneity causes variation in the yield and quality of the indigenous tree

General approaching method

Figure 2.1: Overview of the project approaching method

Evaluate growth capacity of some indigenous tree

Calculating survival rate

Investigating vegetation cover, shrubs

Synthetic, analyze and evaluate the data

Make conclusion and propose solutions to maximize plantation efficiency

2.5.2.1 Inheritance method

During the course of the investigation, some of the materials are available at the research unit could be inherited:

 Data on natural conditions, people, socio-economic in the study area

 Various types of designed maps planted in the study area

Previous research results on research content of different topics

2.5.2.2 Field-work method

Establish standard plot: the plots are set up in an area of 500 m2 (25x20) with the length of the plot parallel to the contour line, the width perpendicular to the contour line Plots are based on the Pythagorean theorem to form angular edges

The trees are numbered in the course of the measurement and are observed for annual data collection The indicators including: growth rate (Hvn, D1.3, Dt), survival rate (%), trees’ quality, shrubs, vegetation cover and pests

 Trees height (Hvn): is measured by the Blumleiss with precision up to 0.1 (m) or using

a pole with carved, accurate to (cm)

 Diameter at breast height – DBH (D1.3): First step is to measure the perimeter of all trees with circumference greater than 18 (cm) by using a 2-meters tape with 0.1 (cm) accuracy The diameter is calculated by the following equation:

D1.3 = C/

 Canopy diameter (Dt): is calculated by measuring the leaf shape in two directions East-West, South-North with tape

 Survival rate was determined by counting dead trees in the plot

 Trees’ quality is determined by the classification of good, medium and poor trees The classification criteria are based on the growth and development patterns of the species

pests; Medium trees are medium growth with morphologically unbalanced; Poor trees are poor growth and stunted

 Pests are identified through visual inspection in the forest by eyes and magnifying glass

2.5.2.3 Data analyses method

After field-work survey, data processing on computer with the support of Exel 5.0 software and SPSS software to process data and calculate mean value of the height, diameter at breast height, canopy diameter

Use statistical mathematical methods in forestry to handle the survey criteria Specifically:

 Calculate sample characteristics according to each plot:

 Calculate sample characteristics:

- Average sample X (mean values: D1.3, Hvn, Dt)

X =fi.xi/n

- Standard error sample

- Coefficient of variation CV = (SD/X ) * 100

- Sample variance S2

 Identification of specific distributions:

- Distribution of trees by diameter N/D1.3

 Calculate average growth criteria of investigated indigenous species:

 The average diameter at breast height (D1.3) growth per year:

 The average height (Hvn) growth per year:

 The average canopy diameter (Dt) growth per year:

 Statistics the trees’ quality by percentage

 Status of vegetation cover, shrubs:

 Statistics on the number of major species, average height, average coverage, quality per plot

 Make a comment about the qualitative relationship between the variation in these

indicators and the variation in the growth capacity of indigenous plants

Average diameter at beast height

Total tree age

D1.3/ year =

Average height growth

Total tree age

Hvn/year =

Average canopy diameter

Total tree age

Dt/ year =

CHAPTER 3 NATURAL, SOCIO-ECONOMIC CONDITIONS OF RESEARCH AREA

The center for environmental research is located in Binh Thanh commune - Cao Phong district - Hoa Binh province The functions of the center are scientific research, technology transfer, consultancy and participation in international cooperation training on environmental monitoring in mountainous areas in the north, forest hydrology, forest land and forest ecology systems The headquarter located in the watershed of the Da river plays an important role in protecting the environment and limiting floods

Currently, the center manages an area of 354.80 ha of forest land allocated by the Da River Forest Enterprise for research and 0.87 hectares of land allocated by the Hoa Binh Provincial Committee for working offices The management forest area is mainly concentrated in the basin of the Da River, with the main function of watershed protection The

Da river watershed is a protected area that plays an important role in the socio-economic development of Hoa Binh province in particular and the Northwest region in general

In the past few years, along with the Hoa Binh dam construction, irrigation was inadequate, the cultivation practices on uneven sloping lands of local people resulted in the forest resources being disturbed and severed degradation in both quantity and quality This negatively affects the ecological, socio-economic environment as well as the life of the community in the area

With its assigned functions and tasks, the center has implemented a number of state forestry development programs and projects, contributing to increasing the forest cover, improving the ecological environment and reducing the erosion in the weak ground of Da river reservoir To continue the forest protection and development, monitoring the climate

of some major research models at the Center; Monitor the evolution of some environmental factors in experimental forest models Also, protect 354 ha of existing forests Contribute to the scientific basis for the sustainable management and use of forest

 It borders on Thai Binh commune and Vay Nua commune to the North

 It borders on Thung Nai and Bac Phong commune to the South

 It borders on Thai Binh commune to the West

 It borders on Thung Nai commune to the East

3.1.2 Topographic

The study area is in low mountainous terrain, lying in two main mountains in the direction of East - West, the average height is about 360 m, the highest is Ong Ngoa (558 m), the lowest is the contiguous area with the edge of Hoa Binh lake (120 m) The slope is relatively large, with an average of 16o – 25o, with steep slopes on rocky

cliffs Although the terrain is less divided but due to the steep slope, especially in the western part of the commune, there is a great influence on the organization of production and business in the area, especially agricultural cultivation In the rainy season, erosion and soil erosion often occur, which directly affects the reservoir

3.1.3 Climate

Hoa Binh is a climate-specific province divided into several sub-regions, so it has the climate of mountainous, midland and plain Weather conditions and climate do not follow the general law of specific regions, but depending on the time of the year may change according to the trend of the Northwest, Northeast and Central Highlands or the Northern Delta

Due to geography and terrain conditions, Binh Thanh commune is tropical in the reservoir area and affected by the Northwest monsoon and Southwest wind, and the impact of the storm is negligible

The meteorological observation results of the meteorological station of Hoa Binh province shows that:

- average air temperature 22.5oC; summer temperatures are little changed; the highest

in June (40.7oC) and the lowest in January (14oC)

- Humidity from 80 - 95%

- The annual rainfall is usually unchanged and fluctuates around 1900 mm, the rainy season is concentrated from April to October, accounting for 70% of the total annual rainfall

- The average evaporation from 520 to 900 mm

In general, the climate conditions here are well suited for the growth and development

of many agro-forestry, industrial and fruit crops