Vietnam Journal of Forest Science Number 4-2013

April 14, 2014 by

Analyzing some biodiversity indexes of tree species in limestone forest vegetation of Than Sa – Phuong Hoang Natural reserve

Biodiversity conservation is a matter of concern at whole human society and has a great importance for sustainable development. Phuong Hoang – Than Sa natural reserve one of some rare special used limestone forests in Vietnam with high biodiversity. This study analyzed some biodiversity indexes of tree species such as important value index (IVI), mixed ratio (HL), Shannon – Wiener Index (H’), Simpson Index (Cd) and Renyi Index (Ha). The results shown that tropical rain evergreen broad – leaf restored forest subformation on earth sites with many exposed stone over 500 m at see level has high biodiversity than other subformations, in contrast, forest formations on limestone mountain have lower biodiversity. The array of Renyi indexes can be used to present diversity by combining species richness and evenness.

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Diversity of wild edible plants in the biosphere reserve Cham Island – Hoi An city

This study clarified the biodiversity and ecology of wild edible used as vegetables plants in the biosphere reserve Cham Island, Hoi An city, Quang Nam province. In the study area, were surveyed 20 plots and recorded 43 plant species, belonging to 30 families, in different habitats: evergreen forests, woodlands scattered sparse, shrub – grassland, bare land, fields and along streams. H index ranged from ranged from 0.46 to 1.94 average 1.28; is the lowest in evergreen forest habitats (0.69 – 1.46), scattered sparse woodlands (1.15 to 1.53), grass, shrubs (1.35) and vacant land, rice fields, along streams (0.46 to 1.94). By analyzing the diversity of life forms which people used as vegetables mostly are herbaceous plants (46.51%) and shrubs (20.93%), habitat mainly in mountain, forest edges, forest (55.81%). This study is aimed at creating a database solution for the conservation, development and planning sustainable use of biodiversity resources.

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Construction of productivity prediction model of Hybrid acacia forest in Thua Thien Hue province

Hybrid acacia is predominantly species in forest plantation in Thua Thien Hue province. The study has relied on some factors those have a major influence on the productivity of Hybrid acacia forest those are pure plantation, the same forest age and were harvested at the 6 – years old forest in Thua Thien Hue to build productivity prediction models. The study has used methods of multivariate regression correlation to predict the productivity. The study has test 4 types of regression model in which the qualitative variables can be used as coded variables or Dummy variables. The prediction models have built for the 2 types of forest cultivation model (extensive and intensive) and for overall the study area. With 250 forest plots for building models and 87 forest plots for testing models, the study has tested and built 12 models (4 models for overall study area, 4 models for extensive cultivation, and 4 models for intensive cultivation). The results shown that model with slope and altitude factors are used as the quantitative variables and other qualitative factors are used as Dummy variables will be the best results with the highest regression correlation is 0.92 and lowest relative prediction error is 4.62%. The specific models are: productivity = 54.040 + 21.123 (T2) + 9.194 (Day5) – 14.230 (Day1) – 27.621 (DatE) – 0.322 (dodoc) – 0.022 (docao) – 2.884 (CG2) – 4.539 (Day2) + 3.518 (M3) – 8.989 (N3) – 6.649 (N4). However, it needs to have more in – depth analytical studies to other influences factors on productivity as well as to older Hybrid acacia forests.

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Adaptability and nut yield of Macadamia clones in North West Vietnam

Mohinh Macca

Objectives of the study were to better understand adaptability, growth and nut yield of Macadamia and clonal variation in these traits, information that will support sustainable development of this species in the Northwest region. The study evaluated seven Macadamia plantations in the Northwest region. Macadamia shows good adaptability and reasonable nut yields in several different locations 300 – 700 metres above sea level. A clone trial at Mai Son, Son La province, tested six selected clones and two controls (unimproved seedlings, and cuttings from selected superior seedling trees). Significant differences in annual nut yield were recorded in two successive years over the period 2011 – 12. Clones OC, 246 and 816had the highest yields of the six clones tested, with mean ranging from 2 to 6kg per tree. Nut yields were higher in 2011 than in 2012. Clones 246 and OC maintained the highest consistent nut yields during these two years. Clone 842had high nut yield in 2011 but its yield significantly decreased in 2012. Clone 816had intermediate nut yield and remained stable over the 2 years. We suggest that clones OC, 246 and 816 should be planted in mixture to maintain sustainable yield as well as ensuring maximum cross – pollination. Recommendations on suitable climatic conditions for planting Macadamia are presented, and management issues in Macadamia plantations with respect to the Northwest conditions are also discussed.

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Result of supplemental studies on planting techniques for eucalyptus in some main ecological areas

Supplemental studies on silvicultural techniques were implemented including application of fertilizers and planting densities for afforestation with eucalypts using advanced technical varieties PN10, PN46, PN47, PN3D, PN21 and PN108 in Yen Bai, Hoa Binh, Thanh Hoa, Dak Nong, Lam Dong and Kien Giang provinces, with other varieties SM16, SM23, EF24, EF39, CU91 and U6 in Ca Mau province. The silvicultural experiments comprised two treatments of fertilizer: (1) 200gram of NPK (5 – 10 – 3) + 200gram of Song Gianh organic microbial fertilizer per tree and (2) 200gram of NPK (5 – 10 – 3) + 14gram of microbial inoculum (named MF1) per tree and two treatments of planting densities (1660 trees/ha and 1110 trees/ha). After three years, the average productivity ( m3/ha/yr) of the eucalypt varieties treated with MF1 increased 18 – 41% more when compared to trees treated Song Gianh organic microbial fertilizer in Yen Bai, Hoa Binh and Thanh Hoa provinces. Average productivity did not differ significantly between the two fertilizer treatments in Dak Nong, Lam Dong, Ca Mau and Kien Giang provinces. There were significant differences in growth (diameter and height) of the eucalypt clones in the two planting density treatments in Yen Bai, Hoa Binh and Thanh Hoa two years after planting, but three years after planting, there were no significant differences between the two treatments in all experiment locations. In Yen Bai, Hoa Binh and Thanh Hoa provinces the best eucalypt clones growth volumes were obtained by applying 200gram NPK + 14 gram of MF1 per tree, with a planting density of 1660 trees/ha. Productivity levels reached 38.6 m3/ha/yr, 36.2 m3/ha/yr and 23.6 m3/ha/yr respectively, three years after planting.

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Plant characteristics of mangrove at Dong Long commune, Tien Hai district, Thai Binh province

The mangrove forest natural area at Dong Long commune, Tien Hai district, Thai Binh province is almost the planted forests. The diversity of species compositions is high; the flora of mangrove forests has 66 species belongs to 33 families distributed following 7 community groups. Nevertheless, the plant communities at natural forests showed the most development with 8 species of tracheophyta in two plant assemblages of Trang (Kandelia obovata) – O ro (Acanthus ebrateatus) and Co ngan (Scirpus kimsonensis) – Co cay (Sporobolus virgicicus). The relationships between species of natural forest were highest with the most stable structure of the forest, and the best growth of trees comparated with other mangrove ecology systems. In the reservoirs of aquaculture, the mangrove flora developed towards the degenerated successions with 11 species of two plant assemblages of Trang – Su (Aegiceras cornicudatum) and O ro – Say (Phragmites karka); or only included one assemblage as Trang – Ban (Sonneratia caseolaris) combined with 8 species in a mixed plantations of Trang and Ban; or Trang combined with three other species on the mono plantation of Trang on the alluvial ground.

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Species diversity and economic value of mangrove flora at Ru Cha, Thua Thien Hue province

This paper presents the study results of species diversity and economic value of mangrove flora in Ru Cha. The results have identified 27 species mangrove flora of 26 genera, 22 families, 2 phylums included Polypodiophyta and Magnoliophyta. Magnoliophyta dominate. Among 27 species in Ru Cha mangrove flora, there are 10 true mangrove species (MS) and 17 mangrove associated species (MAS). Besides, this research has added eight new species at Ru Cha that compared to the list of species of the previous document. Mangrove flora at Ru Cha have a lot of valuable uses, such as timber, firewood, medicinal, food, etc. In particular, there are 18 species of medicinal plants, 12 species of timber, 5 species of bonsai, 6 species of food, 5 species of fiber, 3 species for tannin and 3 species for other utility. The total economic value of Ru Cha mangrove was estimated 1.27 billion dong/year, including 84.2% of direct value, 6.2% of indirect value and 9.6% of non – using value.

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The diversity of plant species in Mu Ca and Ta Tong Commune, Muong Te Distrist, Lai Chau Province

Natural forests in Mu Ca and Ta Tong commune, Muong Te district, Lai Chau province are important ecosystems with high diversity including rare plant species. Results of survey showed that there are 541 plant species of 390 genera, 135 families, belong to 4 orders of vascular plants. The diversity of floral system following to these 4 levels was also analyzed. Comparing with some other Conservation Areas and National Parks in Northern Vietnam, flora in Muong Te are diverse in species composition and quantity of families and genera. The research defined 10 high diversity families which Euphorbiaceae is the most diverse with 31 species. According to Vietnam Red Data Book (2007) 56 rare plant species are identified. 05 species are belong to IUCN 2007 red list while 07 ones are in the endangered list by the Decree No. 32/QD-CP. 22 endemic plant species and 06 Northwest typical plants were also recognized.

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A new species of adinandra jack. (theaceae) from Vietnam

Adinandra hongiaoensis H.T. Son & L.V. Dung (Theaceae), a new species from Hon Giao Peak, Bidoup Nui Ba National Park, Lam Dong province, is described and illustrated. It is similar to A. poilannei, but differs in its leaf blade 35 – 45 ´ 8 – 12cm, base cordate, pedicel short, petal pubescent on back side.

 

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Structural and dynamic properties of natural forest in Hang Kia – Pa Co conservation reserve

This paper presents the structure of forest in Hang Kia Pa Co Conservation Reserve based upon data collected from 6 permanent sample plots. The objective of the research is natural board leaved evergreen forest (IIIA3, IIIB). Forests are under strong variations in structure. Recruitment: 18%, mortality: 0 – 12% base on diameter breast height. Dead trees in small diameter breast height class, just joined the canopy. Use mathematical functions to simulate the mortality, recruitment, transition of forest trees. On that basis, can predict the structure of the forest in the future.

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Determining the optimal financial rotation age for Hybrid acacia plantations at Luong Son forestry company, Hoa Binh province

At present, the rotation age for Hybrid acacia plantation is normally fixed at 5 or 6 years by experience without conducting timber productivity evaluation and financial analysis; therefore, the gained profit per area of the plantation was rather low. This study determined per ha productivity, portfolio of different types of timber, and conducted financial and sensitive analyses for Hybrid acacia plantations at different rotation ages (5,6,7,8, and 9 years) at Luong Son forestry company to provide basics for choosing optimal rotation age in terms of economics. The results showed that age of rotation has great effects on standing volume, productivity, portfolio of different types of timber, and NPV of Hybrid acacia plantation. The timber productivity and percentage of logs with high diameter classes (could be sold at high prices) were positively increased by length of rotation (from 5 to 9 years). When increasing the rotation age, the revenue and income increased faster and at higher level compared to the costs because of the increments of timber productivity and percentages of high priced logs at the long rotations. At the low interest rates (8.5% and 10.0% per year), financial indicators NPV and NPV/ha/year had positive relation with the length of the rotation; of which there is a sharp increment of these indicators from the age of 6 years to the age of 7 years, then gradually increased at longer rotations (8 and 9 years). When the interest rates were set at higher level (12.0% and 14.0% per year), the optimal financial rotation were determined at 7 years. To gain higher net profit in Hybrid acacia plantation establishment, it recommends that the forest owners should extend the age of plantation rotation to at least 7 years instead of 5 or 6 years as usual.

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Research on effects of soil factor to soil erosion under some vegetation in Luong Son distric, Hoa Binh province

Soil is the main object of rain erosion, the more or less of soil erosion depend much on the soil structures and soil surface condition. The research’s results indicate that soil surface condition is rough and rough the less soil erosion. Furthermore, the soil surface covered by grass, the soil erosion decreases significantly. In the other hand, the structures of the soil also can cause the erosion. The different soil types have different erodibility. This study used variable combination of soil surface condition (ratio of rock, rocky – Đ, %) with porosity of soil (X, %) to analyze and build erosion prediction equations. The results demonstrate the feasible test.

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Evaluating the potential land for growing of Amomum longiligulare in forest garden in Yen Bai commune, Ba Vi district, Ha Noi city

The research site was conducted in Yen Bai commune, Ba Vi district, Ha Noi in order to evaluate the potential land for growing of Amomum longiligulare in forest garden. The research results indicate that the bulk density is in the range of 1.127 to 1.284g/cm3, finding out the soil of research site is quite closely; the soil moisture is in the range of 23.11 to 27.65%. The soil texture is from light to medium loam (the content of clay particles is from 24.08 to 27.06%). Soil is strong acid, pHKCl from 4.0 to 4.06. The soil properties are good for growing such as medium levels of total nitrogen content, from 0.12 to 0.19%; rich total of P2O5, from 0.15 to 0.2%; rich total of K2O, from 0.63 to 0.71%; very poor to poor levels of digestible nitrogen, from 1.759 to 2.752mg/100g; plenty of digestible P2O5, from 8.727 to 11.567mg/100g; much abundace of digestible K2O, from 82.3 to 170.12mg/100g. Overall, the soil propertities are suitable for growing Amomum longiligulare. However, when growing Amomum longiligulare, note that comprehensive land preparation, organic fertilizer addition to increase soil porosity, pouring fresh water or choosing an appropriate growing season to increase the soil moisture, lime addition to reduce the soil acidity and the suitable nitrogen fertilizer addition to increase the disgetible nitrogen content.

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Reproductive characteristics of Tokay gecko (Gekko gecko Linnaeus, 1758) in captivity

Captive farming of the Tokay gecko has recently begun in some provinces in Vietnam. However, the supporting knowledge on species’ biology, ecology, behavior, reproduction and husbandry techniques is limited. In this study, the captive geckos were monitored from 2011 to 2012. The study results show clear signs for distinguishing the sex of the geckos. The male has two rows of holes along the thigh forming a V shape and two dark dots under the anus. The female’s markings are uncertain. The breeding season begins in March when their environment begins to warm. Gecko reproduction reaches its peak during the period from May to August. The reproductive season ends in October as their environment cools again. Geckos usually lay 2 eggs per batch, but may sometimes lay 1 or 3 eggs. The incubation period is about 90 – 100 days. Gecko eggs can hatch in normal environmental conditions. Captive geckos should be provided with adequate food, bamboo and wooden boxes for the highest reproductive success.

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