Natural regeneration of evergreen broad leaved forest in the thuong tien nature reserve, kim boi district, hoa binh province

INTRODUCTION

Thuong Tien nature reserve located in Kim Boi district is a reserve of evergreen broad

The Limestone Mountains leaved forest reserve covers a total area of 7,308 hectares, including approximately 4,894 hectares of forested land, with around 4,657 hectares being natural forest and 237 hectares of plantation forest Additionally, there are 1,254 hectares of non-forested land As one of the few remaining natural forest areas in Hoa Binh province and the Northwest region, this reserve plays a crucial role in protecting valuable ecosystems, particularly at lower mountain elevations below 700 meters.

The reserve is home to several gymnosperms, including Taxus wallichiana (Thông đỏ) and species from the Podocarpaceae family (Thông tre) Some of these plants are globally threatened, such as Vatica cinerea (Táu mật), classified as Endangered (EN), and Excentrodendron tonkinensis (Nghiến), highlighting the importance of conservation efforts in this area.

Amoora dasyclada (Gội đỏ) is an endangered species, while Fernandoa bracteata (Đinh vàng), Vatica subglabra (Táu nước), and Excentrodendron tonkinensis (Nghiến) are vulnerable species listed in Vietnam's Red Book The nature reserve is characterized by a lush tropical rain evergreen forest, home to a diverse and rich flora, including these rare and threatened plant species.

Research on the natural regeneration of forests has attracted significant scientific interest, particularly in understanding biodiversity and ecosystem dynamics While numerous studies focus on flora and fauna diversity, there is less focus on the structure, regeneration processes, and resilience of natural forests The primary goal of this research was to analyze the composition, quantity, quality, and phenotypic distribution of regeneration trees on the ground, as well as their vertical distribution, to identify optimal forest management solutions Consequently, I conducted a thesis titled “Natural regeneration of evergreen broad-leaved forests in the Thuong Tien Nature Reserve, Kim Boi District, Hoa Binh Province,” contributing valuable insights into forest regeneration dynamics.

LITERATURE REVIEW

Basic concepts

Forest regeneration, as described by Phung Ngoc Lan (1986), is a biological process characterized by the appearance of new generations of wood species within forest ecosystems under conditions such as canopy gaps, forest clearings, post-mining, or after cultivation and harvesting Seedlings play a vital role in replacing old trees and restoring the fundamental components of the forest, primarily the forest floor Natural regeneration features have prompted extensive scientific research worldwide to develop a solid understanding and foundation for forestry practices However, tropical forest regeneration remains complex and under-studied, with most research focused on economically valuable species.

Researchers on forest regeneration identify two main types: continuous regeneration and streak regeneration Continuous regeneration occurs in climates that support diverse species and age groups, leading to regular regeneration periods throughout the year However, only shade-tolerant species at early stages can survive beneath the forest canopy, highlighting the importance of suitable environmental conditions for sustainable forest growth.

Seedlings often experience weak and slow growth during this period; however, favorable conditions enable small trees to develop quickly and participate in the upper canopy layer, leading to rapid forest development Streak regeneration, also known as hole regeneration, occurs mainly in light-adapted species, particularly in older primary forests where large trees have died In these gaps with sufficient light, strong regeneration takes place, primarily involving species that grow rapidly, have short lifespans, and are softwood or seed-based Over time, these fast-growing species gradually overshadow the original species adapted to shaded conditions, contributing to the formation of the high canopy layer in the forest.

Study in foreign countries

Tropical forests often undergo continuous regeneration due to their complex composition and diverse tree populations According to Van Steenis, the high forest canopy contains a mixture of tree ages, enabling regeneration to occur throughout the year Only shade-tolerant plants in early growth stages can survive beneath the dense canopy, supporting the ongoing renewal of these vibrant ecosystems.

Studies by Bava (1954) and Budowski (1956) have shown that natural regeneration in tropical Asian forests under the canopy is generally sufficient, with many regenerating trees holding significant economic value To support healthy forest regeneration, implementing silvicultural measures is essential to promote the development and sustainable regeneration of trees beneath the forest canopy.

Research by Nava (1954) and Budowski (1956) demonstrated that regeneration capacity in tropical rainforests heavily depends on species diversity A key characteristic of successful rainforest regeneration, especially for light-adapted species, is hole regeneration, which occurs through gaps in the canopy This process highlights the importance of canopy openings in facilitating the natural renewal of rainforest ecosystems.

Holes in the rainforest significantly alter environmental conditions such as light, humidity, and temperature under the forest canopy These openings influence the composition and regeneration of tree species, favoring fast-growing species adapted to increased light availability Typically, species that regenerate in these gaps are short-lived and do not normally appear in the mature forest composition, often originating from seeds dispersed from distant areas or introduced by animals and humans According to Van Steenis (1956), the presence of holes promotes dynamic changes in forest structure by facilitating the growth of pioneer species suited to disturbed conditions.

2.2.2 Survey methods for natural regeneration

Establish square plot with the area: 25m 2 , investigating the regeneration trees have economic value (diameter 1 - 2.5cm) origin from the seeds and have good condition

Following Lamprecht (1989), the plot was divided into sub-plots focusing on seedlings with a diameter at breast height (DBH) less than 10 cm and height over 1.3 m A total of 12 sub-plots, each measuring 4 m² (2 m x 2 m), were established along two perpendicular transects crossing the center of the main plot to systematically investigate trees with heights ranging from 0.3 m to 1.3 m.

This study established a 10,000 m² (1 hectare) investigation area, subdivided into 25 plots, each measuring 400 m² (20m x 20m) At each corner of every plot, a 25 m² sub-plot (5m x 5m) was designated for seedling investigation This precise and efficient method proved highly suitable for ecological research on forest regeneration, making it ideal for extensive studies in tropical rainforest regeneration processes.

Sapkota and Oden established a 25m² plot (5m x 5m) with the center at the intersection of two diameters to determine the area of the hole and evaluate seedlings at heights ≥ 2m A 4m² sub-plot (2m x 2m) was set up in the corner of the main plot to measure root diameter, focusing on seedlings with heights between 0.2 and 2 meters Additionally, the study involved measuring the height and diameter at breast height (>20cm) of all surrounding trees within the plot area.

According to Jans et al (1993) and Wulf (2007), the hole area is determined by dividing the area beneath a small triangle formed by the joint vertices within the hole, using measurements of distance and azimuth from the center to points on the plot's edge in the surrounding forest The study selected eight positions around the hole's edge corresponding to azimuths of 0°, 45°, 90°, 135°, 180°, 225°, 270°, and 315°, measuring the distance from the center to each point These points were connected, forming polygons consisting of eight triangles that collectively represent the hole's area Additionally, a 25m² (5m x 5m) sub-plot was established within each triangle to analyze the characteristics of tree regeneration, providing valuable insights into forest regeneration patterns.

Study in domestic

Research on natural forest regeneration in Vietnam began in the 1960s, highlighting its importance as a biological process characterized by the replacement of old trees with new growth In Vietnam, forest regeneration shares the general features of tropical forests but is complicated by human activities Natural regeneration occurs in both primary and secondary forests, even in plantations with fertile soil, where regeneration is influenced by the surrounding high canopy trees The composition of regenerating trees typically mirrors that of the high forest layer, driven by seed dispersal from mature trees, development of buds on roots, or seed input from external sources Understanding these processes is essential for effective forest management and conservation in Vietnam.

According to Thai Van Trung (1963, 1970, and 1978), the natural regeneration of tropical forests in northern Vietnam exhibits characteristic patterns of tropical forest recovery It involves the continuous regeneration of shade-tolerant species beneath the forest canopy, alongside the pioneering regeneration of light-loving (photophilic) species in canopy gaps.

Research in Yen Bai, Ha Tinh, Quang Binh and Lang Son according to Do Thi Ngoc

Le (2007) demonstrates that layer structure regeneration is closely linked to tall trees, with a particular tree species exhibiting a high coefficient in the composition of the upper forest layer This species tends to have similar coefficients in the regeneration class, indicating a consistent relationship between mature trees and regeneration patterns Understanding these correlations is essential for forest management and conservation efforts, emphasizing the importance of high trees in shaping regeneration dynamics.

Vu Dinh Hue classifies forest regeneration into three levels based on tree density: good regeneration with over 12,000 trees per hectare, medium regeneration with 4,000 to 8,000 trees per hectare, and poor regeneration with 2,000 to 4,000 trees per hectare This study specifically focuses on the density of regeneration trees as a key indicator of forest recovery and health.

Hole regeneration is one of the common characteristics of the natural forest regeneration, when assessing the distribution of regeneration tree by level height Ta Thi

Huong (2009), Nguyen Thi Kha (2009) have concluded: like with the regeneration under the canopy, the amount of regeneration in the holes decrease when their height increases

2.3.2 Survey methods for natural regeneration

According to Do Thi Ngoc Le (2007), although multiple plots were used, the small investigation area for each plot limited the accuracy of the results To address this, the study established five plots, each measuring 25m² (5m x 5m), with four sub-plots located at the corners and two additional sub-plots positioned at the diagonal intersections Despite having fewer plots, their larger size aimed to improve the precision and reliability of the research findings.

According to Hoang Thi Tuyet (2010), each forest assessment involves establishing one main plot of 10,000 m² (100m x 100m) in a typical location This primary plot is subdivided into 25 sub-plots, each measuring 400 m² (20m x 20m) From these, 13 sub-plots are randomly selected for detailed data collection, ensuring representative sampling across the forest area.

According to Tran Van Con (2010), when studying regeneration in a 1-hectare (10,000m²) plot, two types of plots were used for investigation A circular plot with a radius of 15 meters (area of 707m²) was designated to assess regeneration of diameter D1.3 from 1 to 10cm Additionally, twelve sub-plots, each measuring 4m² (2m x 2m), were used to investigate regeneration with diameter D1.3 less than 1cm.

According to the normative silviculture QPN 14-92 established by Vietnam's Forestry Ministry and now the Ministry of Agriculture and Rural Development, the natural forest regeneration prospects in Vietnam typically involve trees achieving heights of 1-2 meters or more Most researchers agree that regeneration is successful when the young trees reach heights equal to or exceeding the shrub layer, with overall growth quality considered average or better, indicating healthy forest development.

Conclusion

Research on natural regeneration encompasses a diverse range of methods, subjects, and findings, significantly advancing our understanding of forest renewal processes These studies have clarified key issues related to natural regeneration, providing valuable insights for forest management and conservation Specifically, my thesis emphasizes the statistical analysis of natural regeneration characteristics at the study site, highlighting important patterns and factors influencing forest recovery.

Based on various research methods, my thesis employed sampling techniques according to Lowdermilk (1927), including establishing plots of 1000m² (40m x 25m) and sub-plots of 4m² (2m x 2m) to accurately capture regeneration data The sub-plot size was selected to facilitate efficient investigation and ensure representation of real regeneration conditions Additionally, tools such as a 50-meter tape measure, compass, and GPS were used to enhance data collection accuracy during the research process.

GOALS AND OBJECTIVES

Determine characteristics of natural regeneration of evergreen broad-leaf forest in the Thuong Tien nature reserve

1.Investigated the status of natural forest at Thuong Tien nature reserve

2.Statistic about the characteristics natural regeneration in the study site

Current status of evergreen broad-leaf forest in Thuong Tien reserve: i Classify the forest status ii Elevation iii Total area iv Basic structure of the forest

• High trees (name species, formula composition)

• Shrub trees (name species, height average)

Characteristics of the natural regeneration class

• Origin and quality of regeneration trees

• Phenotypic of distributions regeneration trees

STUDY SITES AND METHODS

Natural conditions

Thuong Tien Nature Reserve, established as the first protected area in Hoa Binh Province, was designated by Decision 94/CT dated August 9, 1986, by the Chairman of the Council of Ministers Covering a total area of 7,308 hectares, it spans across three communes: Thuong Tien, Kim Tien in Kim Boi District, and Quy Hoa in Lac Son District This protected area plays a vital role in conserving the region's unique natural ecosystems.

Located in Lac Son district, the area is bordered to the north by Hop Dong, Dong Bac, Vinh Tien, and Tu Son To the east, it borders Kim Binh, Kim Boi, Kim Truy, and Cuoi Ha in Kim Boi district The southern boundary is shared with Tuan Dao and My Thanh in Lac Son district This strategic location offers easy access to neighboring districts, making it ideal for development and connectivity.

Abutting on the West: Xuan Phong, Yen Thuong, Yen Lap (Cao Phong district)

Thuong Tien nature reserve located in areas with geographic coordinates:

Figure 4.1 Map of study site in Thuong Tien nature reserve

Thuong Tien Nature Reserve features a rugged mountainous topography with elevations ranging from 300 to 1,073 meters above sea level, with Cot Ca Peak being the highest point The reserve's forested areas are predominantly situated on steep slopes, divided into two main mountain ranges: Cot Ca and Cot Co, with only a small, relatively flat forest zone located between the communes of Quy Hoa and Thuong Tien Its terrain is characterized by deep valleys, narrow river basins, rocky surfaces, and rugged landscape features, primarily composed of slopes exceeding 35 degrees.

Thuong Tien Nature Reserve, situated in a tropical monsoon climate zone, experiences cold winters, rainy summers, and a dry season lasting approximately 2.1 to 3.0 months As one of the region's highest rainfall areas, it significantly contributes to the upper catchment of the Boi and Buoi rivers in Hoa Binh Province, making it a vital ecological and hydrological zone.

The monitoring data of Hydrometeorology Station in Kim Boi (20 0 40’ North latitude,

105 0 32’ East longitude) shows, a long of rainy season from April to October, concentration on 90.38% of the total of rainfall throughout the year

The Northeast monsoon occurs regularly in winter, creating a dry season in nature reserves with less distinct dry and wet periods compared to the Northwest monsoon, which brings low temperatures, high humidity, and drizzle rain The Southwest monsoon causes hot, dry early summer weather followed by rainfall, while the Southeast monsoon, blowing from the East Sea, is prevalent in late summer and early fall, bringing rain to the reserve and influencing the region's climate patterns.

The region's mild climate, shaped by the influence of three air masses, prevents prolonged drought conditions From November to March, the area experiences a long dry season, with December, January, and February characterized by minimal rainfall—less than twice the average monthly temperature—creating ideal conditions for regeneration tree growth With an annual average rainfall of approximately 1,600 mm, the climate is heavily influenced by three main wind directions, supporting healthy forest development.

The study area experiences an average humidity of 85%, with a high of 89% and a low of 80%, creating a moist environment conducive to diverse flora and fauna The average temperature stands at 23°C, ranging from a peak of 29°C to a low of 10°C, with frost occasionally forming on cold days at Cot Ca Peak and Thung Hill Overall, the climate of the Thuong Tien Nature Reserve provides favorable conditions that support the growth and development of a wide variety of plants and animals, contributing to its status as a diverse and stable ecosystem.

Below is a bioclimatic diagram of Kim Boi district, Hoa Binh province (references from 2000):

I II III IV V VI VII VIII IX X XI XII Years

The bioclimate diagrams of Kim Boi in Hoa Binh reveal that the recording station, situated at an altitude of 100 meters, has been monitored over 24 years for temperature and 26 years for precipitation The area experiences a mean annual temperature of 22.8°C and receives an average of 2,256 mm of rainfall annually During the coldest month, the mean daily minimum temperature is 13.0°C, with an absolute minimum of 2.1°C, while the warmest month sees a mean daily maximum of 33.1°C The temperature varies by approximately 7.6°C throughout the year The diagram categorizes the year into different periods: a dry period crucial for plant growth, a humid period, and a per-humid period Additionally, it highlights times when the mean daily minimum temperature drops below 15°C and periods during which the absolute daily minimum falls below 5°C, indicating seasonal variations critical for local ecosystems.

The Thuong Tien Nature Reserve features a complex hydrological system comprising four major river systems and numerous small streams that flow year-round The Thuong Tien stream, which flows into the Boi River heading southeast, is a key water source for the region Additionally, smaller streams in Lac Son district contribute to the water supply for communes in Kim Boi and Lac Thuy districts Water for agriculture in these downstream districts primarily depends on the Boi River However, seasonal rains often cause flooding, disrupting transportation and other activities, highlighting the need for watershed management to regulate downstream water flow and mitigate flood risks.

Characteristics of livelihood, economic and social

Thuong Tien Nature Reserve is home to 2,089 households across three communes, with a total population of 10,641 residents The majority of the population, approximately 9,914 people (93.2%), rely on agriculture as their primary livelihood Meanwhile, around 727 residents (6.8%) are engaged in other trades, reflecting a predominantly rural community with an economy centered on farming.

The ethnic: in an area with two main ethnic are Muong ethnic accounting for 97.1% and other ethnic groups including the Kinh, Thai and Tay ethnic accounting for 2.9% of all

The labor: the whole region has 4535 employees, mainly depends on agriculture have

4130 people accounting for 91.07%, the remaining employees depends on other trades

Agriculture is the primary manufacturing activity in the region, with most residents earning their livelihoods through farming, livestock, and poultry raising The local community faces economic challenges, as the average annual food income per person is only 285 kg This highlights the reliance on agriculture as the main income source and the need for development to improve living standards.

The communes within the reserve face high poverty rates, with Thuong Tien at 52.8%, Kim Tien at 50%, and Quy Hoa experiencing the highest at 70.2% Notably, Thuong Tien commune is involved in 135 development programs aimed at poverty alleviation.

Recent years have seen limited changes in the region's economic structure, with a notable shift towards tourism development and service activities Kim Boi holds significant potential for tourism growth, including attractions like Kim Boi mineral water parks, Mat Troi waterfall in Kim Tien commune, Cuu waterfall in Tu Son commune, and resorts in Vinh Yen This economic transformation can improve local residents' living standards and reduce the environmental impact of agriculture on forests within Thuong Tien Nature Reserve.

Study site

Mostly is special use forest and not affected by external factors

Total area of Thuong Tien nature reserve about 7308(ha) includes: forested area about 4894(ha), natural area about 4657(ha) and 237(ha) plantations forest, non-forested land 1254(ha)

The areas of forest in reserve are divided into the categories as follows:

Table 4.2 Categories of forest in Thuong Tien

Number Kind of forest Area (ha)

In the study site of the reserve, establish 3 plots with area 1000m 2 , at an elevation >

400 m above with sea level, with an average slope about 35 0

Collecting secondary data include: the natural conditions, economic, the map of the study area, references.

Survey methods

Collect the current forest status map

Classify the forest status based on the experience of the local people

Sample plots establishing: i Each plot have area: 1000m² (40m x 25m) ii Sub-plot have area: 4m 2 (2m x 2m)

Each plot will be split as follows:

Figure 4.3 Structure of the sample plot diagram

Figure 4.4 Location of research area

In each plot, we record the diameter at 1.3 meters height (D1.3) in centimeters, calculating the average diameter (D) for accuracy Tree heights (H) are measured using a Blumleiss tape measure to ensure precise data collection Additionally, a list of tree species with a diameter greater than 6 cm is compiled for each sub-plot, facilitating comprehensive forest analysis and management These measurements are essential for assessing tree growth, biomass estimation, and supporting sustainable forestry practices.

Table 4.3 Data summary of high tree floor

In sub-plot need determine: i Name of shrub ii Average height of shrub iii Cover of shrub

This article explores the species and origins of regeneration trees, distinguishing between bud regeneration and seed regeneration methods It also examines the decentralization of tree heights, categorized into size classes such as less than 0.5 meters, 0.5 to 1 meter, 1 to 1.5 meters, 1.5 to 2 meters, and above 2 meters Additionally, the quality of regeneration trees is assessed, classified as good, medium, or bad, providing insights into the overall health and development in each sub-plot.

- Good trees: trees with good growth, twig development, and no pests

- Medium trees: normal development, little pest

- Bad trees: no top of the tree, pests, poor growth

Data of regeneration trees class:

Table 4.4 Data summary of regeneration trees class

Data processing methods

4.6.1 Method determine the composition regeneration trees

Regeneration tree composition is determined by analyzing the ratio of different species or species groups within sub-plots This involves identifying the set of regeneration trees across all sub-plots, including species and individual counts, to assess species diversity Key metrics include the total number of species and the total number of individuals present in the sub-plots Calculating the average number of individuals per species helps evaluate regeneration patterns, using specific formulas to ensure accurate assessment of forest regeneration health and diversity.

N: is the total number of individuals of the species m: is the total of species

X: is the average number of individuals per species Determine the number of species, name of species participated in the formulation composition i Number trees of species X is participate in the formulation composition

Determine the formula composition of each species:

In ecological studies, Ki represents the coefficient composition of species i, while Xi denotes the number of individuals of that species N stands for the total number of individuals across all species The composition formula is used to determine the contribution of each species to the overall community, with the rule that species having a Ki value greater than 0.5 are excluded from the composition calculation This approach helps to accurately assess species diversity and community structure by focusing only on species with significant contributions.

Density of regeneration tree (for sub-plot):

Ni/ha = (3) ni: total trees in sub-plot

S0: total area of sub-plot Density of regeneration tree in each plot:

4.6.2 Determine the phenotypic of distribution regeneration trees

The article classifies plant height into four levels: H < 0.5m, 0.5m < H < 1m, 1m < H < 1.5m, 1.5m < H < 2m, and H > 2m It examines above-ground regeneration distribution by aggregating data on regeneration trees within sub-plots To analyze the regeneration pattern, the average number of individuals in each height category is determined using a specific formula, providing insights into the distribution and regeneration dynamics of the vegetation.

The average number of individuals per location (X) is calculated by dividing the total number of individuals (N) by the number of sub-plots (a) within each research site To assess the variability in tree distribution across different sub-plots, the variance of the number of trees is determined using a specific formula This approach helps quantify the dispersion of tree counts between sub-plots, providing insights into demographic patterns within each research location.

Xi: number of individuals in sub-plot of each research location Sx²: variance between the numbers of trees in sub-plot of each research location iv Determine the ratio K:

If: K1 distributions regeneration is distributed cluster

4.6.3 Statistical methods for the quality of regeneration trees

Quality regeneration trees (determine rate of regeneration trees):

The percentage regeneration prospects of trees can be calculated using the formula: (ni / N) x 100, where ni represents the number of regeneration trees with the potential to develop, and N is the total number of regeneration trees Understanding this rate helps assess the overall health and regeneration potential of forest ecosystems, providing valuable insights for sustainable forestry management Accurate measurement of regeneration prospects ensures effective conservation strategies and supports the successful recovery of forest populations.

RESULTS AND DISCUSSION

Current status of evergreen broad - leaved forest

The Thuong Tien Nature Reserve comprises protected forests and specific forest areas, with some regions designated as strictly protected zones to conserve biodiversity The remaining areas serve as ecological restoration zones and are utilized for various sustainable land uses, supporting both conservation efforts and local livelihoods.

The nature reserve is situated in the highest mountain regions of Lac Son and Kim Boi districts, featuring primarily yellow and gray feralit soils formed on Sa Thac and Bazich rocks.

Thung Hill in Quy Hoa commune is characterized by abundant granite rocks scattered throughout the valley and large streams, indicating a rugged terrain The region features significant deposits of yellow feralit soil, rich in sandy content, which is highly susceptible to erosion and runoff when surface vegetation is removed.

Total area of nature reserve: 7308(ha), an elevation large than 400 m above with sea level and an average slope about 35 0

High trees

Forests are characterized by their tree species composition, which reflects the overall structure and diversity of the ecosystem The formula composition of forest species serves as a key indicator for assessing biodiversity, sustainability, and ecological stability Understanding forest structure is essential for effective forest utilization, as it directly influences regeneration capacity and plant recovery within the ecosystem.

Formula composition utilizes Ki coefficients to illustrate species contributions within an ecosystem A Ki value of 0.5 or higher indicates that the species has significant ecological importance and actively participates in shaping the community structure Consequently, each plot’s formula composition can be determined based on these Ki coefficients, providing insight into species dominance and ecological roles in the habitat.

1.71 Vernicia montana Lour + 1.71 Ginoniera subequalis Planch + 1.22 Peltophorum tonkinensis + 0.98 Oroxylon indicum (L) Vent + 0.73 Pterospermum heterophyllum Hance +

0.73 Buretiodendron hsienmu Chun et How – 2.88 other species

In plot 1, total of species: 15 species, number of tree: 41 trees and have 6 species involved in formula composition

2.35 Pterocarya tonkinensis + 1.76 Michelia mediocris Dandy + 1.18 Machilus bombycina Gagnep + 0.88 Dipterpcarpus retusus + 0.59 Parashorea chinensis Wang Hsie + 0.59 Nagaia fleurii (Hickel) De Laub + 0.59 Lithocarpus – 2.03 other species

1.67 Malotusco chinchinensis +1.43 Michelia mediocris Dandy + 1.19 Ginoniera subequalis Planch + 0.95 Aporosa dioica Mucll + 0.95 Dipterpcarpus retusus + 0.71 Lithocarpus + 0.71

Parashorea chinensis Wang Hsie - 2.4 other species

(Plus sign in formula composition: shows species have high coefficient of composition Minus sign: not important species, low coefficient and does not appear much in the forest stands)

In each plot, the density of high tree layers varies from 340 to 420 trees per hectare, with approximately 14-15 species present Among these, 6-7 species actively contribute to the forest composition, with dominant species groups exhibiting high Ki coefficients, indicating strong adaptation to local climate and land conditions Notably, valuable species such as Lithocarpus and Vernicia montana Lour have high Ki coefficients, underscoring their importance; thus, management measures should be implemented to optimize their density and promote healthy growth for future dominance in the high tree layer For dominant but less valuable species, targeted measures are needed to reduce their impact, improve light and nutrient availability, and facilitate replacement by more valuable species in the future high tree layer.

The formula composition of tall trees is determined using the IV% (Important Value) indicator, which illustrates the species' proportional representation within the ecosystem Species with an IV% of 5% or higher are considered ecologically significant and are included in the formula composition analysis This approach helps to accurately assess the species diversity and dominance in each plot, providing essential insights into the ecological structure of the studied area.

18.03 Vernicia montana Lour + 13.76 Ginoniera subequalis Planch + 12.17 Peltophorum tonkinensis + 11.33 Lithocarpus + 9.54 Oroxylon indicum (L) Vent + 6.75 Pterospermum heterophyllum Hance + 6.25 Buretiodendron hsienmu Chun et How + 5.62 Saraca dives

26.10 Pterocarya tonkinensis + 16.77 Michelia mediocris Dandy + 12.40 Machilus bombycina Gagnep + 9.57 Dipterpcarpus retusus + 6.78 Parashorea chinensis Wang Hsie +

5.62 Nagaia fleurii (Hickel) De Laub – 22.76 other species

23.01 Michelia mediocris Dandy + 17.77 Malotusco chinchinensis + 15.76 Ginoniera subequalis Planch + 7.79 Aporosa dioica Mucll + 6.46 Lithocarpus + 6.06 Dipterpcarpus retusus + 5.01 Parashorea chinensis Wang Hsie - 17.61 other species

(Plus sign in formula composition: shows species have high coefficient of composition Minus sign: not important species, low coefficient and does not appear much in the forest stands)

Each plot experienced a variation in species diversity, increasing from 14 to 15 species Among these, 6 to 8 species are involved in formula composition, reflecting their significance within the ecosystem The IV% indicator of dominant species rose from 77.24% to 83.29%, highlighting their strong adaptation to the local climate and land conditions These findings demonstrate a dynamic and resilient plant community well-suited to the environment.

Shrub layer

Various shrubs are commonly found at the study site, including Microsorum pteropus (Boston Fern), Dicranopteris linearis (Old World fern), Rubus alceaefolius Poir (Raspberry), Randia dumetorum Benth (Găng), and Rhodomyrtus tomentosa (Downy Rose Myrtle) These plants typically grow to an average height of 0.42 to 0.68 meters, contributing to the area's rich botanical diversity.

The type of shrub layer significantly influences the growth and development of regeneration trees by competing for nutrients and light under the forest canopy While shrubs create favorable conditions for shade-tolerant plants, they can impede the development of regeneration trees, leading to a high density of young trees but a low overall regeneration success rate Rapid shrub growth and increased competitiveness often result in shrubs dominating the area, thereby hindering seed germination and seedling establishment, especially when seeds land on the shrub layer and lack direct contact with the soil Conversely, seeds dispersed by wind, animals, or humans that reach the soil have better chances to germinate and develop into healthy seedlings, highlighting the importance of seed dispersal mechanisms and ground contact for successful forest regeneration.

Regeneration trees class

The composition and regeneration of trees serve as key indicators of a stand's relevance to its business objectives, with the future structure expected to feature a dominance of taller, high-value trees A survey conducted across 42 sub-plots (each measuring 4m²) distributed evenly within three larger plots (each 1000m²) provided data to assess the current regeneration patterns These findings offer valuable insights into the development and sustainability of forest stands, informing effective forest management and planning.

Formula composition of regeneration trees are recorded like follow:

0.96 Ginoniera subequalis Planch + 0.84 Vernicia montana Lour + 0.84 Acacia auriculiformis + 0.84 Cinnamomum bejolgata + 0.72 Markhamia stipulate (Roxb) Seem +

0.72 Buretiodendron hsienmu Chun et How + 0.60 Castanopsis tonkinesis + 0.60 Côi núi (local name) + 0.60 Pterospermum heterophyllum Hance + 0.60 Peltophorum tonkinensis –

1.06 Lithocarpus + 0.93 Michelia mediocris Dandy + 0.93 Castanopsis tonkinesis + 0.80

Peltophorum tonkinensis + 0.80 Vernicia montana Lour + 0.80 Nagaia fleurii (Hickel) De

Laub + 0.67 Pterocarya tonkinensis + 0.67 Pterospermum heterophyllum Hance + 0.67

Sterculia lanceolata Cav + 0.53 Cinnamomum bejolgata + 0.53 Machilus bombycina Gagnep

0.86 Aporosa dioica Mucll + 0.86 Machilus bombycina Gagnep + 0.74 Saraca dives Pierre + 0.74

Endospermum chennenese Benth + 0.74 Michelia mediocris Dandy + 0.74 Markhamia stipulate

(Roxb) Seem + 0.74 Ginoniera subequalis Planch + 0.62 Lithocarpus + 0.62 Buretiodendron hsienmu

Chun et How + 0.62 Pterospermum heterophyllum Hance – 2.72 other species

(Plus sign in formula composition: shows species have high coefficient of composition Minus sign: not important species, low coefficient and does not appear much in the forest

The species composition in the forest plots shows an increase from 10 to 11 species, with a total of approximately 19–24 species per plot Dominant species account for a high percentage of the composition, ranging from 7.28% to 8.39%, while many other species have similar proportions Notably, some species such as Vernicia montana Lour and Lithocarpus exhibit high economic value and contribution to the overall composition Certain dominant species like Pterospermum heterophyllum Hance and Michelia mediocris Dandy are consistently present across all three plots To promote forest health and sustainability, measures should include planting additional species with both economic and conservation value, selectively removing less valuable trees, and facilitating the regeneration of valuable species These strategies aim to maintain structural stability, ecological diversity, and the protective functions of the forest in the future.

5.4.2 Phenotypic of distributions regeneration trees:

Investigate distribution regeneration trees on ground follow Poisson distribution standard is K indicator The results are recorded in the tables below:

Table 5.1 Phenotypic of distributions index

From data above, distribution of regeneration on the ground in the plots is distributed evenly, suitable for the study area is rich in forests and primary forests

Refers to the sources of regeneration trees is referring to regeneration problems born from seed or from buds

Overall, the forest's regeneration rate varies depending on environmental conditions, with forests that have been exploited showing a higher regeneration rate from buds compared to seed-based regeneration This emphasizes the importance of forest ecosystems in protecting land, water resources, and wildlife, which require a stable root system developed by a diverse range of trees The origin of tree regeneration was assessed based on whether it originated from seeds or buds at various height levels, with the detailed results recorded in the accompanying tables.

Table 5.2 Statistics numbers of tree follows origin and height level

Origin and height level of regeneration trees

The chart below will show the origin of regeneration trees and height trees levels in the study area (in both 3 plots):

Figure 5.1 Regeneration trees and division according to height levels and origin

Seed-origin regeneration offers long-term forest stability and structural integrity, making it essential for large timber production and sustained protective functions While bud regeneration enables rapid growth suited for early-stage business needs and temporary protection, seed-based regeneration ensures the development of resilient forests capable of meeting future ecological and economic demands Combining both methods optimizes forest recovery, balancing quick establishment with long-term sustainability.

For each forest type, quality requirements and qualities for regeneration tree species also different

For the forests with the purpose of protection, requires trees to grow well and root development, good disease resistance With this idea, the thesis has statistics the number of

Table 5.3 Rate of quality of regeneration trees

The regeneration rates of trees vary significantly, with good regeneration ranging from 41.98% to 45.33%, medium regeneration from 34.52% to 34.66%, and poor regeneration from 19.05% to 23.46% Although these proportions differ, the relatively low dominance of good trees highlights the need for targeted management measures Implementing strategies to reduce competition for light and nutrients among shrubs can enhance regeneration quality and promote healthier tree development.

Table 5.4 Rate of regeneration prospects

Bad trees (>0.5m) regeneration prospects trees regeneration no prospects trees rate of regeneration prospects

Regeneration prospects are trees with height ≥ 0.5 - 1m or more, or greater than the

The study area exhibits forest conditions with a regeneration rate of 50.67% to 53.01%, indicating favorable environments for healthy tree regeneration The robust growth and development of regeneration trees on the forest floor create promising prospects for future forest expansion These conditions support sustainable forest development and enhance biodiversity within the nature reserve, contributing to the overall ecological health of the area.

The chart below will show the rate of regeneration prospects in the study area:

Figure 5.2 Rate of regeneration prospects in both 3 plots

5.4.6 Relationship between of high trees and regeneration trees class

Table 5.5 Relationship between of high trees and regeneration trees class

Buretiodendron hsienmu Chun et How

The data indicates that the number of species present in the high trees layer is lower than in the regeneration layer For example, Plot 1 shows five species in the high trees layer, all of which also appear in the regeneration layer with high composition coefficients, including Vernicia montana Lour, Ginueira subequalis Planch, and Buretiodendron hsienmu Chun.

In Plot 2, there are four species, including Pterospermum heterophyllum Hance and Peltophorum tonkinensis, that appear in both the high trees floor and regeneration layers, such as Michelia mediocris Dandy, Nagaia fleurii (Hickel) De Laub Conversely, in Plot 3, the number of species present in both layers decreases to three, including Aporosa dioica Mucll, Michelia mediocris Dandy, and Peltophorum tonkinensis This variation indicates differences in species distribution between the plots across different forest strata.

Trees are more commonly found in regeneration layers but are less prevalent in the upper forest floors due to natural impacts and irregular seed dispersal Additionally, insects and animals contribute to seed dispersion from various locations, affecting distribution In contrast, certain species dominate the high forest layers while being scarce in regeneration layers, primarily because of competition for light and nutrients, as well as the influence of shrubs and vines, which hinder the development of new regeneration trees necessary for future forest composition.

High trees and regeneration trees mutually influence each other by providing seeds for on-site forest regeneration The offspring of regeneration trees are closely connected to the tall parent trees in various ecological aspects Changes in the number of individuals among these trees can lead to significant shifts in forest ecology Regeneration trees can originate from seeds produced by the mother plant or be planted from external sources The absence of certain species in the understory is partly due to poor seed dispersal or germination failure, resulting in weak or dead seedlings and impacting overall forest composition.

Current status of evergreen broad - leaved forest

Thuong Tien Nature Reserve's forest status includes protected forests and specific forest types, primarily situated on yellow and gray feralit soils The protected areas feature land characterized by these fertile soils, supporting diverse ecosystems Notably, the Thung hill area in Quy Hoa commune is characterized by abundant granite rocks within the valley and sizable streams, indicating a rugged landscape This region also exhibits the regional distribution of yellow feralit soils, which contain large amounts of sand, making them prone to erosion and runoff when surface vegetation is depleted.

Nature reserve have elevation large than 400 m above with sea level and an average slope about 35 0

High trees and shrubs

From the results obtained in the implementation process thesis, I can make some conclusions as follows:

In high trees, 14 to 15 species are involved, with 6 to 7 species commonly included in the formula composition Some species are adapted to light, grow quickly, and are less valuable, such as Cratoxylon Prunifolium Kurtz (Đỏ ngọn), Malotusco chichinchinensis (Ba soi), and Gynoniera subequalis Planch (Ngát) Conversely, other species are considered valuable, including Lithocarpus (Dẻ), Lithocarpus pseudosundaicus (Sồi xanh), and Cinnamomum bejolgata.

Several shrub species are commonly found, including Microsorum pteropus (Dương xỉ), Dicranopteris linearis (Guột), Rubus alceaefolius Poir (Mâm xôi), Randia dumetorum Benth (Găng), and Rhodomyrtus tomentosa (Sim), all averaging between 0.42 to 0.68 meters in height and maintaining a healthy status These shrubs play a vital role in the ecosystem, supporting biodiversity and soil stability Additionally, regeneration trees are crucial for restoring forest areas, ensuring sustainable growth and ecological balance Their presence indicates a well-established and resilient environment, essential for maintaining natural habitats.

Regeneration trees class: Some species involved in the regeneration trees from 19 to

24 species which have from 10 to 11 species involved in formula composition There are some species have high rate of composition and economic value such as: Vernicia montana

Lour, Lithocarpus Some dominant species appear in both 3 of plot: Pterospermum heterophyllum Hance, Michelia mediocris Dandy

Distributions of regeneration trees in the plot follow height level decrease when height increased This shows the level of adaptation of some plants with their living conditions

Distribution of regeneration on the ground in the plots is distributed evenly, suitable for the study area is rich in forests and primary forests

In all survey of transect in the study area, regeneration trees from seed have rate higher than regeneration trees from buds

The quality of regeneration trees in the area we are investigating look good, only a small number of trees have poor quality

1 Tran Van Con, 2009 Động thái tái sinh rừng tự nhiên lá rộng thường xanh vùng núi phía bắc The journal of Agriculture and Rural Development Number 7/2009

2 Tran Van Con and partners, 2010 Nghiên cứu các đặc điểm lâ học (diễn thế, cấu trúc, tổ thành, tái sinh (TS), tăng trưởng, khí hậu thủy văn, đất, …) của một số hệ sinh thái rừng (HSTR) tự nhiên chủ yếu ở Việt Nam Final report of the threads, Forest Science Institute, Ha

3 Vo Dai Hai and Tran Van Con, 2001 Kết quả nghiên cứu bược đầu về khả năng phục hồi rừng tự nhiên lá rộng thường xanh sau nương rẫy ở Tây Nguyên Information science and forestry number 1/2001:7-10

4 Do Thi Ngoc Le, 2007 Nghiên cứu đặc điểm tái sinh và lựa chọn phương pháp điều tra tái sinh rừng tự nhiên tại xã Đú Sáng, huyện Kim Bôi, tỉnh Hòa Bình Master thesis of Forest

Science, Forestry University, Hà Tây

5 Tran Viet Ha, 2010 Growth and quality of indigenous bamboo species in the mountainous regions of Northern Vietnam.Ph.D thesis, the Faculty of Forest

Science and Forest Ecology, Georg-August-Universitọt Gửttingen

6 Kasensne, J.M, 1987 The influence of selective logging, felling intensity and gap site on the regeneration of a tropical rain forest in the Kibale Forest Reserve, Uganda, Michigan

State University East Lasing, MI

7 Pham Minh Toai, 2012 Structure and regeneration of lowland tropical moist evergreen forest in North and Central Vietnam PhD thesis, Goettingen University, Goettingen,

APPENDICES Name of species appear in the study site:

Number of tree Latin name Vietnamese name

5 Oroxylon indicum (L) Vent Núc nác

6 Pterospermum heterophyllum Hance Lòng mang

7 Buretiodendron hsienmu Chun et How Nghiến

8 Saraca dives Pierre Vàng anh

10 Liquidambar formosana Hance Sau sau

12 Markhamia stipulate (Roxb) Seem Đinh

14 Endospermum chennenese Benth Vạng trứng

20 Parashorea chinensis Wang Hsie Chò chỉ

21 Cryptocarya lenticellata H.Lec Nanh chuột

26 Aporosa dioica Mucll Thẩu tấu

27 Streculia lanceolata Cav Sảng nhung

29 Vatica subglabra Merr Táu nước

31 Schefflera octophylla Hams Chân chim

32 Canarium album Lour Trám trắng

34 Manglietia conifera Dandy Vàng tâm

36 Symplocos dolichitricha Merr Dung đen

39 Cratoxylon Prunifolium Kurtz Đỏ ngọn

High trees use Ki coefficient:

Number Name species (Vietnamese name) Ni Ki

7 Buretiodendron hsienmu Chun et How 3 0.73

Number Name species Ni Ki

7 Nagaia fleurii (Hickel) De Laub 2 0.59

High trees use IV% (imporatant value):

Numbers of species Name of species Ni N% G% IV%

7 Buretiodendron hsienmu Chun et How 3 7.32 5.18 6.25

Plot 2 Numbers of species Name of species Ni N% G% IV%

7 Nagaia fleurii (Hickel) De Laub 2 5.88 5.36 5.62

Numbers of species Name of species Ni N% G% IV%

15 Buretiodendron hsienmu Chun et How 2 4.76 2.82 3.79

Name of species Height average Status Plot Sub- plot

1 1 Dương xỉ (Microsorum pteropus), guột (Dicranopteris linearis), mâm xôi (rubus alceaefolius poir) 0.55 G

2 Cỏ tranh (Imperata cylindrica), găng (Randia dumetorum 0.63 G

3 Dong rừng (Phrynium placentarium), mây 0.53 G

4 Găng (Randia dumetorum Benth), sim (Rhodomyrtus tomentosa) 0.52 G

5 Dương xỉ (Microsorum pteropus), mâm xôi (rubus alceaefolius poir) 0.62 G

6 Cỏ lăng (Medicago sativa), riềng rừng (Alpinia conchigera

7 Mâm xôi (rubus alceaefolius poir), cỏ tranh (Imperata cylindrica) 0.61 G

8 Găng (Randia dumetorum Benth), cỏ lăng (Medicago sativa) 0.53 G

9 Cỏ chân gà (Cynodon dactylon), cỏ tranh (Imperata cylindrica) 0.58 G

11 Dong riềng (Canna edulis), bùm bụp (Mallotus apelta Muell

12 Dong riềng (Canna edulis), cỏ tranh (Imperata cylindrica) 0.59 M

13 Bướm bạc (Mussaenda pubescens Ait.f.), cỏ tranh (Imperata cylindrica) 0.68 M

14 Mâm xôi (rubus alceaefolius poir), chít 0.54 G

2 1 Dương xỉ (Microsorum pteropus), dây leo 0.52 G

2 Mây, ráy (Alocasia odora), dong riềng (Canna edulis) 0.68 G

3 Dương xỉ (Microsorum pteropus), guột (Dicranopteris linearis) 0.42 M

4 Mâm xôi (rubus alceaefolius poir), dong rừng (Phrynium placentarium) 0.64 M

6 Mâm xôi (rubus alceaefolius poir), guột (Dicranopteris linearis) 0.50 G

9 Dong riềng (Canna edulis), cỏ chân gà (Cynodon dactylon) 0.43 G

10 Bùm bụp (Mallotus apelta Muell Arg.), dây leo 0.56 G pteropus)

12 Bướm bạc (Mussaenda pubescens Ait.f.), muống tuồng 0.37 G

13 Muống tuồng, ba chạc (Euodia lepta) 0.58 M

3 1 Dương xỉ (Microsorum pteropus), cỏ xước (Achyranthes aspera L.) 0.41 G

2 Gừng rừng, ráy (Alocasia odora) 0.46 G

3 Găng (Randia dumetorum Benth), mây 0.55 G

4 Cỏ tranh (Imperata cylindrica), dây leo 0.59 G

5 Chít, cỏ chân gà (Cynodon dactylon) 0.39 M

6 Dứa dại (Pandanus tectorius), dương xỉ (Microsorum pteropus) 0.61 G

7 Muống tuồng, dong riềng (Canna edulis) 0.55 G

8 Dây leo, sim (Rhodomyrtus tomentosa) 0.54 G

9 Cỏ chân gà (Cynodon dactylon), mây 0.41 G

10 Sầm, sim (Rhodomyrtus tomentosa), dong riềng (Canna edulis) 0.52 G

11 Cỏ tranh (Imperata cylindrica), ráy (Alocasia odora) 0.48 M

12 Mây, cỏ chân gà (Cynodon dactylon) 0.60 M

13 Dó lông, cỏ chân gà (Cynodon dactylon) 0.42 M

14 Muống tuồng, bùm bụp (Mallotus apelta Muell Arg.) 0.61 G

8 Nagaia fleurii (Hickel) De Laub 6 0.80

Tiêu đề	Natural Regeneration of Evergreen Broad-Leaved Forest in the Thuong Tien Nature Reserve, Kim Boi District, Hoa Binh Province
Trường học	Hoa Binh University
Chuyên ngành	Forestry and Conservation
Thể loại	Research Paper
Năm xuất bản	2015
Thành phố	Hoa Binh

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