Gap regeneration patterns of woody tree species in tropical evergreen moist forest at the ba vi national park

MINISTRY OF AGRICULTURE AND RURAL DEVELOPMENT VIETNAM FORESTRY UNIVERSITY STUDENT THESIS GAP REGENERATION PATTERNS OF WOODY TREE SPECIES IN TROPICAL EVERGREEN MOIST FOREST AT THE BA VI NATIONAL PARK Major: Natural Resources Management (Advanced Curriculum) Code: D850101 Faculty: Forest Resources And Environmental Management Student: Nguyen Thi Nham Class: K55 Natural Resource Management Student ID: 1053090440 Course: 2010 - 2014 Advanced Education Program Developed in collaboration with Colorado State University, USA Supervisor: Dr Pham Minh Toai i Hanoi, November 2014 ACKNOWLEDGEMENTS To complete this report, my research has received a lot of support from organizations and individuals involved Firstly, I would like to send my most sincere thanks to Dr Pham Minh Toai - Lecturer of Silviculture Faculty - Vietnam Forest University who has dedicated guides and helps me throughout the implementation process of research I also sincerely thank the cooperation and help of the leadership and staffs in Ba Vi National Park Thanks for help of friends in the days of data collection in the field Although I was tried by my best to implement this study, but my knowledge, duration of the study and references are limited, so that the research inevitably flawed I look forward to receiving comments from teachers, friends and all readers for completing this research I sincerely thank you all! Author Nguyen Thi Nham TABLE OF CONTENT I INTRODUCTION II OVERVIEW OF THE RESEARCH AREA III STUDY OBJECTIVES IV STUDY METHODS 4.1 Data collection methods 4.1.1 Selection of the study areas 4.1.2 Gap sampling 4.2 Data analysis methods 10 V RESULTS AND DISCUSSIONS 12 5.1 Gap characteristics and size class distributions 12 5.2 Characteristics of regeneration in the gaps 14 5.2.1 Growth characteristics of canopy tree surrounding studied gaps 14 5.2.2 Density and tree species composition in the gaps 15 5.2.3 Height distribution of regenerated trees 17 5.2.4 Density and quality of regenerated trees 20 5.3 Effect of factors to gap regeneration 23 5.3.1 Effect of under the forest canopy in around gap to gap regeneration 23 5.3.2 Effect of shrubs and vegetation to gap regeneration 24 5.4 Recommend some silvicultural solutions to promote restoration process of forest gaps at the study area 26 VI CONCLUSIONS AND RECOMMENDATIONS 28 6.1 Conclusions 28 6.2 Recommendations 29 LIST OF FIGURE Figure 2.1: Map of Forest Statuses in Ba Vi National Park Figure 4.1: Gap area measurement and sample plot design Figure 5.1: The size class distributions of canopy gap 13 Figure 5.2: Distribution of regenerated trees in poor forest 18 Figure 5.3: Distribution of regenerated trees in medium forest 18 Figure 5.4: Distribution of regenerated trees in rich forest 19 Figure 5.5: Quality of regeneration tree in poor forest 21 Figure 5.6: Quality of regeneration tree in medium forest 22 Figure 5.7: Quality of regeneration tree in rich forest 22 LIST OF TABLE Table 5.1: Gap characteristics of the three forest categories 12 Table 5.2: Characteristics of surrounding canopy trees in the gaps 14 Table 5.3: Species compositions of regeneration tree in the gaps 15 Table 5.4: Distribution of regenerated trees according their height 17 Table 5.5: Density of seedlings and saplings in studied areas 20 Table 5.6: Distribution of regenerated tree according the quality 21 Table 5.7: Relations between the high tree composition and regeneration tree 23 Table 5.8: Effect of shrubs and vegetation to regeneration 25 I INTRODUCTION Canopy openings caused by mortality, windfall and removal of single or multiple mature trees have been widely recognized as an important source of spatial heterogeneity for the establishment, growth and survival of tree species in the tropical rainforest (Denslow, 1987; Clinton, 2003) They are also considered as one of the important phases in the forest restoration cycle They furthermore play an important role as key processes in the forest structural dynamic, in forming species richness and species composition (Richards, 1952; Brokaw, 1985; Denslow, 1987; Li et al., 2005) as well as in the maintenance of the diversity of tree species diversity (Clinton, 2003) Previous studies revealed that germination, growth, survival and mortality of seedlings and saplings of tree species in gaps vary among species (Lawes et al., 2007) They depend on both biotic and abiotic factors, on particular characteristics of the canopy gaps (Denslow, 1987; Osunkjoya et al., 1992; Gray and Spies, 1996; Taylor et al., 2006; Sapkota et al., 2009; Sapkota and Odén, 2009) and on the competition among the tree species (Poulson and Platt, 1989) cited by Gray and Spies, 1996) for light, water and nutrient resources (Gagnon et al., 2004) In many forest types canopy gaps are an initial phase for the start of a new regeneration cycle of the canopy tree species (Fajardo and de Graaf, 2004) Small gaps promote shade tolerant tree species to geminate and to establish (Clebsch and Busing, 1989; Whitmore, 1989) Large gaps promote pioneer or light demanding tree species (Gray and Spies, 1996; Yamamoto, 1996; Li et al., 2005) and enable opportunist tree species to grow through release of suppressed saplings from the canopy cover to absorb and use opened light energy to reach maturity (Brokaw, 1987; Schupp et al., 1989; Chandrashekara and Ramakrishnan, 1993; Gagnon et al., 2004) Moreover, the previous studies on canopy gaps also stated that gaps are normally heterogeneous in size and vary consistently within and between forest types (Brokaw, 1985b; Osunkjoya et al., 1992) This due to the fact that the gaps are formed by different numbers, sizes and foliage structures of falling/extracting tree species A variation of gap sizes results in difference gap light intensities, temperatures and soil moistures Therefore, the richness, composition and diversity of tree species that colonize and fill the gaps in general and the mortality, recruitment of seedling and sapling tree species in particular can vary considerably within and between the forest types (Clinton, 2003; Sapkota et al., 2009) Obviously, these regeneration patterns are difficult to predict (Clinton, 2003) especially in tropical evergreen forest communities Heterogeneous changes in microclimatic and other conditions after gap formation are a fundamental regime for the promotion of pioneer seedlings and the suppression of established and re-grown saplings (Drobyshev and Nihlgard, 2000; Clinton, 2003; Sapkota et al., 2009) A variation in the microclimate, resulted from heterogeneity of the gap sizes, plays a key driver in the forest succession (Kneeshaw and Bergeron, 1998; Clinton, 2003) It is also considered as an important mechanism of the species coexistence (Orians, 1982) and a maintenance mechanism of a high tree species diversity in tropical rainforest communities (Connell, 1978; Sapkota et al., 2009) In tropical region, the loss, fragmentation and degradation of rainforests lead to a great variation in the regeneration patterns of woody tree species in canopy gaps Understanding these complicated patterns therefore improve a limited knowledge on the variation of the species richness, species growth, composition and species diversity in the canopy gaps of different forest stands/categories It can help researchers to predict dynamics of the tree species composition within the canopy gap in comparison with the regeneration pattern of tree species beneath the forest canopy The roles of canopy gaps in the regeneration process and in community dynamics had been pointed out repeatedly, surprisingly, most of the studies on the forest regeneration in Vietnam were mainly focused on the regeneration beneath the canopies of natural forests or artificial plantations Limited studies that focused on gap regeneration have been implemented by researchers such as Phuong (1970), Hue (1975), Tam (1987), Kha (2009), Hoang Thi Tuyet (2010), Nguyen Thi Thiet (2012) but they are quite dispersed Characteristic of this regeneration pattern needs clarity in order to apply them in forest management We hope that, results of this study in Ba Vi National Park will contribute enhance know about gap regeneration characteristic and recommend some silvicultural solutions to promote restoration process of forest gaps at the study area II OVERVIEW OF THE RESEARCH AREA Study was conducted at the Ba Vi National Park, Ba Vi District, Ha Noi City The park, with coordinates from 21°01 to 21°07' N latitude, from 105°18' to 105°25' E longitude, falls completely into the North region of Vietnam and is located in the Ba Vi mountain range and about 48 km from North-West of Ha Noi (Figure 2.1) The park was established in 1991 with total area of 7,377 The total natural area of Ba Vi National Park at the time of the survey is 10,782.7 ha, including forest land area of 8,192.5 (accounting for 75.98% of the total natural area of the park) Of which 4,200.5 hectares of natural forest (accounting for 51.27% of the forest land), 3,992 hectares of planted forests (accounting for 48.73%) High mountain terrain and large forest covering bring to Ba Vi region the cool climate, especially in summer (from April to October) In winter, covering cloud creates a deeply impressive landscape The park is situated on a mountain range running north-east and south-west its peak at Vua Peak (1,296 m), Tan Vien Peak (1,226 m) and Ngoc Hoa Peak (1,120 m) Figure 2.1: Map of Forest Statuses in Ba Vi National Park About tourism potential, the natural beauty and special geographic and climate feature converge into the park’s ecosystem make it becomes one of four mountainous ecological tourism centers besides Da Lat, Sapa, and Tam Dao Regarding flora and fauna resources, the park is home to more than 1,200 kinds of plants, of which 21 species were mentioned in Viet Nam’s Red Book 2007 Recently, according to statistical results of scientists, Ba Vi National Park has 812 species of vascular plants Of which, there are tree species including Allomorphia baviensis, Begonia baviensis, Tabemaemontana baviensis, Pinanga baviensis, Lasianthus langkokensis, Fargesia baviensis, Magiolia baviensis, Carex baviensis It is also home to 15 rare and precious plants such as blue cypress, bamboo, and three-shot fern, silver leaf bassia and wooden fern In addition, 45 mammal species, 115 bird species, 27 amphibians species, 61 reptiles, 86 species of insects, of which 23 precious and some rare species were listed in the Viet Nam’s Red Book (2007) such as coolies, horse bears, yellow pangolins, white pheasants, monkeys, leopards, bears and flying squirrels Vegetation in the area of Ba Vi National Park consists of main types: 1) Low montane subtropical broadleaved evergreen moist lower montane subtropical forest (Montane forest, Subtropical woodlands); 2) Mixed forest of broadleaved evergreen trees and coniferous subtropical lower montane trees; 3) Low montane tropical broadleaved evergreen rain forest (tropical woodlands, bamboo forest, plantations) III STUDY OBJECTIVES Objectives of this study are: (1) To identify and compare gap regeneration patterns among different forest categories (2) To assess the relationship between gap-size classes and regeneration patterns (3) To identify factors that may influence the abundances of dominant seedlings and saplings (4) To recommend some silvicultural solutions to promote restoration process of forest gaps at the study area 70 Regeneration ratio (%) 60 50 Good 40 Medium 30 Bad 20 10 Center gap Edge gap Location Figure 5.6: Quality of regeneration tree in medium forest 90 Regeneration ratio (%) 80 70 60 50 Good 40 Medium Bad 30 20 10 Center gap Edge gap Location Figure 5.7: Quality of regeneration tree in rich forest In the all two location of three research categories (center and edge of gaps), good quality medium quality are higher than bad quality Regeneration ratio of good quality occupy from 61.4% to 78%, ratio of medium quality occupy from 17% to 29.4% , ratio bad quality was only occupy from 3.4% to 10.5% 22 Generally, quality of regeneration at the three research categories were relatively good, have ability growth about diameter and height The collected results regarding density, origin, quality of regeneration demonstrated that regeneration tree in the study area have ability to form a new generation in the future However, at the research categories even more ratio of medium quality and still ratio of bad quality, thus the need to have the active methods as promote regeneration and combine to give supplementary growth, cutting liana and shrubs to make advantage conditions for regeneration to reach the better quality 5.3 Effect of factors to gap regeneration 5.3.1 Effect of under the forest canopy in around gap to gap regeneration The relationship between the mother plant composition and regeneration composition are indicator reflecting the inheritance of storey regeneration and storey mother plant, this relationship is reflect the degree of mother plant sowing However, the level inherited in species composition of regeneration tree depends largely on ability to provide the seed of mother plant, germination conditions, ecological characteristics and ability the competition of each species Dominant level in species composition at three research categories were aggregated in the table 5.7: Table 5.7: Relations between the high tree composition and regeneration tree Number of species Categories Poor forest Medium forest Rich forest Location Center gap Edge gap Center gap Edge gap Center gap Edge gap Number of regeneration Inheritance Sorensen Under tree ratio index the Regeneration inherited (%) (BC) forest tree from canopy the high tree 15 30 28 12 12 80 0.89 17 14 93.33 0.88 17 15 50 0.64 27 27 90 0.95 31 28 100 0.95 29 29 100 1.02 23 The result from table 5.7 showed ratio of the high tree have regeneration tree inheritance relatively high, vary from 50% to 100% Ratio inheritance from the high tree of storey regeneration tree at rich forest was the highest in the three categories However, the results that access the level inheritance of regeneration tree and the high tree by Sorensen index shows, BC index fluctuations from 0.88 to 1.02 at the poor and rich forest, BC > 0.75, demonstrate that random regeneration tree in the study area, no inheritability from high tree composition In the three categories, only medium forest, in center gap BC < 0.75, demonstrate that regeneration tree composition have the relationship closely with the high tree composition 5.3.2 Effect of shrubs and vegetation to gap regeneration The shrubs and vegetation are one of the factors effect to grow and develop of regeneration tree, special the nutritional competition and light of under the forest canopy The studies showed when average cover decrease, the shrubs and vegetation increase, advantage for regeneration tree that shade tolerant, younger tree development, but they will interfere when seedlings grow up The shrubs and vegetation is the main factors decision of the number of regeneration prospects in the forest Density of regenerated trees in under the shrubs and vegetation canopy are very high, but regeneration tree is occupy low ratio by rapid growth and development of the shrubs and vegetation faster, the stronger competition and gradually transgress regeneration tree The shrubs and vegetation is also affect to ratio of germinate when seeds were sown in place If seeds fall off the forest floor and having favorable conditions, contact with the soil will germinate and grow well Contrary, if seeds fall off the shrubs and vegetation thick canopy will not to contract with the soil, the seed was not germinate 24 Table 5.8: Effect of shrubs and vegetation to regeneration Shrubs and vegetation Categories Location Average height (m) Edge gap Regeneration density (N/ha) 50 4,826 2,702 40 7,207 3,152 35.3 4,099 2,585 30 5,957 3,479 25 3,507 2,165 20 3,611 2,283 1.12 Center gap Medium forest Edge gap 0.83 Center gap Rich forest Edge gap Regeneration density prospects (N/ha) Average cover (%) Center gap Poor forest Regeneration 0.8 In the three research categories, the shrubs and vegetation canopy includes: Microsorum pteropus, Callisia fragrans, Heliatropium indicum, Celastrus hindsii Benth.et Hook, Eupatorium triplinerve, Boehmeria nivea, Paspalum scrobiculatum, Gnetum Montanum, Amomum villosum var xanthioides, … with average height from 0.8 to 1.12 m and average cover from 20% to 50% Regeneration density at the three categories is fluctuating from 3,507 to 7,207 (trees/ha) To look in the Table 5.8 we can see that average cover increase, regeneration density decreasing , average cover was 20% and regeneration density was 3,507 trees/ha; when average cover is upward 50% then regeneration density is 4,826 trees/ha Demonstrate that the shrubs and vegetation has large effect to regeneration density, caused by the shrubs and vegetation are intensive growth and transgress nutritional space, light of regeneration tree, make regeneration density decrease Competition of the shrubs and vegetation concomitant made regeneration density decrease and quality of regeneration less from which made regeneration ratio prospects decrease Generally, at the three research categories, regeneration consistent with low the canopy average cover 25 Regeneration ratio prospects: Regeneration prospects was regeneration height higher than or equal to the average height of the shrubs, vegetation and above quality medium Average height and average cover of the shrubs, vegetation direct decision to regeneration density Average cover of the shrubs, vegetation was low, regeneration density and regeneration density prospects were high And when average cover of the shrubs, vegetation was high, regeneration density and regeneration density prospects were low by competition of nutritional space of the shrubs, vegetation with regeneration tree Wherefore, problems in this was have to regulate the shrubs, vegetation canopy so that were not affect to regeneration tree, cut down the shrubs, vegetation to average cover decrease, facilitate for regeneration tree growth and development, regeneration density prospects increase 5.4 Recommend some silvicultural solutions to promote restoration process of forest gaps at the study area From the studied results, silvicultural solutions need to apply for three research categories (poor, medium, rich forest) includes: delineate an area for protection, forest maintenance, concomitant natural regeneration promotion and combine plantation that ensure ability protection, protective ecology environment and reserve rare gene, biodiversity of natural forest in the Ba Vi National Park Based on the research achieve, I recommend some technical solutions to apply for the study area: Should choose many good seed, have a high ability the adaptation with habitat, environmental conditions in Ba Vi National Park Choose many species have a high economic value and landscape value to create a forest environment friendly Planting the dominant tree in Ba Vi National Park such as: Calocedrus macrolepis, Cinnamomum 26 parthenosylon, Madhuca pasquieri, Magnolia baviensis… to restoration vacant land and bring a high economic value Average cover and average height of the shrubs, vegetation at medium level, however it also affect to regeneration tree layer To make conditions for the sow, scatter seed, germination, growth and development of the regeneration tree layer, need to competition decrease between the shrubs, vegetation and regeneration tree Need to cutting liana, average cover decrease of the shrubs, vegetation, special at the bushy places, have large cover Cleaning, care regeneration prospect, density regulator to improve living space and nutrition for regeneration tree under the forest canopy and in the gap The gaps have large regeneration density, need to regulate to density decrease and make conditions for regeneration tree well grow The larger the area of the gap, the amount of regeneration as much, if the area of gap was too large that regeneration density was not enough, we need additional planting to take the forest space In the necessary conditions and allows may the application to improve forest regeneration conditions for development However, to the silvicultural solutions can be implemented and accepted, we cannot be ignored the conditions of economic – society in the local When apply the silvicultural solutions need to consider ability capital investment, ability manpower, knowledge degree about silvicultural, traditional farming techniques of the people, ability to approach the advancement technique and local knowledge have important meaning in the deployment of the farming techniques impact to the forest 27 VI CONCLUSIONS AND RECOMMENDATIONS 6.1 Conclusions - In 15 gaps within each forest categories (poor, medium, rich), dead tree and broken branches are two main causes of gap formation Average area in the rich forest is the largest (173.17 m2), average area in medium forest was 108 m2, the lowest at the poor forest with average area is 92m2 The fluctuation scope of area in the gaps at the three categories are not large - Species composition of regeneration tree in research categories were relatively diversity and abundance, number of species that attend to species composition formula fluctuating from to 10 species And ratio of regeneration between species was relatively equitable At the different location, species composition was also different - The light source and space condition have larger effect to regeneration species composition in the gap In the center gap, where abundant light source and concentrate many regeneration species of light demanding, fast growing Species of light demanding group includes: Adinadra millettii, Macaranga denticulate, Archidendropsis basaltica, Wightia annamensis, Adinandra, Ichnocarpus polyanthus, Claoxylon indicum…The shade tolerant species group includes: Litsea baviensis, Ficus fulva , Cinnamomum camphora, Camellia, Archidendropsis basaltica, Cinnamomum camphora… - Regenerated composition in the two location of the gaps in the three research categories are diversity and abundance, fluctuating from 34 to 59 regeneration tree Regeneration density in the three categories at medium level, fluctuating from 3507 to 7207 tree/ha Regeneration density prospects from 2165 to 3479 tree/ha 28 - Distribution of regeneration according the height: in the all two location at the three research categories are distributed decrease form, but an decreasing extent of the locations and the different height level are different - Quality of regeneration: at the three research categories, regeneration ratio of good quality is the highest and the lowest regeneration ratio of bad quality Regarding the quality, center gap have quality better than edge gap - Effect of some factors to regeneration tree: area gap and number of regeneration have the relationship closely, the larger area gap, number of regeneration tree as much The shrubs, vegetation have affect to regeneration tree at medium level 6.2 Recommendations - Continue to monitor the regeneration characteristics in the study area in subsequent years to be able to assess regeneration dynamics of forest plant communities as the basis for the development of sustainable forest model in production forest areas nearby - Study the relationship between the primary factors circumstances forest understory as well as in the gap as light, temperature, humidity and soil characteristics to the of forest plant communities in the area of research - The research the effect of fruitful cycle, source of seed to regeneration characteristics 29 REFERENCES English document Brokaw, N.V.L., (1985b) Tree falls, regrowth, and community structure in tropical forests, In: Pickett, S.T.A., While, P.S (Eds.), The ecology of natural disturbance and patch dynamics Academic Press, New York, pp 53-69 Brokaw, N.V.L., (1987) “Gap-Phase Regeneration of Three Pioneer Tree Species in a Tropical Forest”, Journal of Ecology 75, 9-19 Chandrashekara, U.M., Ramakrishnan, P.S., (1993), “Gap phase regeneration of tree species of differing successional status in a humid tropical forest of Kerala”, India Journal of Biosciences 18, 279 Clebsch, E.E.C., Busing, R.T., (1989), “Secondary Succession, Gap Dynamics, and Community Structure in a Southern Appalachian Cove Forest” Ecology 70, 728-735 Clinton, B.D., (2003), “Light, temperature, and soil moisture responses to elevation, evergreen understory, and small canopy gaps in the southern Appalachians” Forest Ecology and Management 186, 243-255 Connell, J.H., (1978), Diversity in Tropical Rain Forests and Coral Reefs: High diversity of trees and corals in maintained only in a no equilibrium state Science 199, 13021310 Denslow, J.S., (1987), “Tropical Rainforest Gaps and Tree Species Diversity” Annual Review of Ecology and Systematics 18, 431-451 Drobyshev, I., Nihlgard, B., (2000), “Growth response of spruce saplings in relation to climatic conditions along a gradient of gap size” Canadian journal of forest research 30, 930 Fajardo, A., de Graaf, R., (2004), “Tree dynamics in canopy gaps in old-growth forests of Nothofagus pumilio in Southern Chile” Plant Ecology 173, 95-105 Gagnon, J.L., Jokela, 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characteristics and their effects on regeneration, dominance and early growth of woody species” Journal of Plant Ecology 2, 21-29 Schupp, E.W., Howe, H.F., Augspurger, C.K., Levey, D.J., (1989), “Arrival and Survival in Tropical Treefall Gaps” Ecology 70, 562-564 Taylor, A.H., Shi Wei, J., Lian Jun, Z., Chun Ping, L., Chang Jin, M., Jinyan, H., (2006) Regeneration patterns and tree species coexistence in old-growth Abies-Picea forests in southwestern China Forest Ecology and Management 223, 303-317 Whitmore, T.C., (1989), “Canopy Gaps and the Two Major Groups of Forest Trees” Ecology 70, 536-538 Yamamoto, S (1996), “Gap regeneration of major tree species in different forest types of Japan”, Plant ecology 127 Vietnamese document Hoang Thi Tuyet (2010), natural regeneration characteristics of vegetation in tropical evergreen moist forest in Bach Ma – Thua Thien Hue National Park, master thesis forest Science Hue, V.D., (1975), Overview of regeneration status of forests in North Vietnam 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forest Science APPENDIX Appendix 01: Symbol name some plants used in the research ID Vietnamese name Latin name Abbreviation Chè sim Adinadra millettii Am Lá nến Macaranga denticulate Md Mỡ Ba Maglolia baviensis Mb Đáng Schefflera octophylla So Kháo Cinnadenia paniculata Cp Bời lời Ba Litsea baviensis Lb Re hương Cinnamomum parthenoxylon Cp Ngõa lông Ficus fulva Ff Ba soi Macaranga denticulata Muell 10 Mần tray Ba Ichnocarpus polyanthus Ip 11 Lộc mại Claoxylon indicum Ci 12 Giổi Michelia balansae Mb 13 Trám Syzygium balsamineum Sb 14 Súm mật Eurya japonica Ej 15 Gội xanh Aglaia perviridis Ap 16 Mỏ chim Cleidio brevipetiolatum Cb 17 Dâu tằm Ficus tristylis Ft 18 Họ trà Camellia C 19 Long não Cinnamomum camphora Cc 20 Giẻ gai Bắc Castanopsis chinensis Cc 21 Trẩu Vernicia montana Vm 22 Phân mã Archidendropsis basaltica Ab Mdm ID Vietnamese name Latin name Abbreviation 23 Long mức Trung Wightia annamensis Wa 24 Chè đuôi lươn Adinandra integerrima Ai 25 Vỏ sạn Osmanthus pedulculatus Opg gagnep 26 Bứa dài Garcinia oblongitolia Go 27 Re bầu Cinnamomum bejolghota Cb 28 Gội trắng Aphanaminix grandiflora Bl Ag 29 Trám rừng Burseraceae B 30 Thôi ba Alangium sinesis As 31 Bồ đề Styrax tonkinensis St 32 Mé cò ke Grewia paniculata Gp 33 Ba bét Mallotus floribundus Mf 34 Hu đay Trema angustifolia Ta 35 Màng tang Litsea cubeba Lc 36 Muối Rhus chinensis Rc 37 Mỡ ba Maglolia baviensis Mb 38 Chẹo thui to Helicia grandifolia Hg 39 Cây óc chó Ficus hirta Fh 40 Côm phờ lơ ri Elaeocarpus griffithii Eg 41 Re Cinnamomum C 42 Rè Machilus M 43 Máu chó bắc Knema tonkinensis Kt 44 Su bắc bắc Alseodaphne tonkinensis At 45 Dâu gia xoan Allospondias lakheonsis Al ID Vietnamese name Latin name Abbreviation 46 Chi li lài Tabernaemontana bovina Tb 47 Trâm tía Syzygium bavienenses Sb 48 Sồi gai ba Lithocarpus sp baviensis Lb 49 Sảng Sterculia lanceolata Sl 50 Dót Eupatorium triplinerve Et 51 Cẩm quỳ Pterospermum P 52 Dầu chuông Delavaya toxocarpa Dt 53 Xơ Harpulia cupanioides Hc 54 Cá đuối trắng Cryptocaria C 55 Hoắc quang Wendlandia W 56 Nguyệt quế Neocinnamomum N 57 Vải guốc Xerospermum noronhianum Xn ... great variation in the regeneration patterns of woody tree species in canopy gaps Understanding these complicated patterns therefore improve a limited knowledge on the variation of the species. .. ratio of species composition ni: number of species N: the total of species 10 + Evaluation the quality of regeneration trees Ratio of regeneration tree with each level was calculated using the. .. tropical evergreen moist forest in Bach Ma – Thua Thien Hue National Park, master thesis forest Science Hue, V.D., (1975), Overview of regeneration status of forests in North Vietnam Forest Inventory