Pretzsch H.,TU Munich |
Biber P.,TU Munich |
Uhl E.,TU Munich |
Dahlhausen J.,TU Munich |
And 9 more authors.
Urban Forestry and Urban Greening | Year: 2015
Tree crown size determines among others tree's growth, carbon sequestration, shading, filtering of fine air particulates, and risk of wind-breaking. The dependence of crown size on species, resource supply, and tree age complicates an accurate evaluation of a tree's space requirement, and its size-dependent functions and services in urban as well as in forested areas. Based on a world-wide dataset of tree crown measurements of 22 common urban tree species we first derived species-specific crown radius-stem diameter relationships for open grown conditions. By cluster analysis we then assigned the 22 species to 5 crown extension types and developed mean relationships of tree height, crown radius, crown projection area, and crown volume depending on tree diameter for each type. This allometric analysis yielded auxiliary relationships which can be used for estimating the species-specific crown size and dynamics at a given tree dimension. We discuss how the results can support the choice and initial spacing of particular species and the assessment and prognosis of their functions and services. © 2015 The Authors.
Kanzaki N.,Japan Forestry and Forest Products Research Institute |
Aikawa T.,Tohoku Research Center |
Maehara N.,Tohoku Research Center |
Thu P.Q.,Vietnamese Academy of Forest science
Nematology | Year: 2016
Bursaphelenchus kesiyae n. sp. is described. The new species was isolated from dead wood of Pinus kesiya during a field survey of nematodes associated with dead pine trees (Pinus spp.). The new species is medium- to large-sized for the genus, with males 690-1059 μm and females 837-1122 μm in body length, and has four lateral lines, six male genital papillae (P1 ventral single papilla is missing or vestigial), a mitten-shaped spicule with clear dorsal and ventral limbs, an indistinctive small and narrow bursal flap, vulva lacking any flap apparatus, and female tail long, tapering and straight or slightly ventrally curved. Based upon its diagnostic morphological characters, the new species belongs to the B. fungivorus group and is closely related to B. thailandae and B. parathailandae, with which it forms a cryptic species complex. However, the new species is distinguished from these two species by the morphology of the male bursal flap and several morphometric values, i.e., the bursal flap of the new species is inconspicuous, or almost lost in many individuals. Molecular phylogenetic analysis inferred from near-full-length SSU and D2-D3 LSU supported the morphological observations, i.e., the new species is molecularly similar to B. thailandae and B. parathailandae, but could be distinguished phylogenetically. Further, differences in molecular sequences in SSU and D2-D3 LSU between the new species and its close relatives are slightly higher than those between B. xylophilus and B. mucronatus, thus, identification of the species status for B. kesiyae n. sp. is considered warranted. © Koninklijke Brill NV, Leiden, 2016.
Fourie A.,University of Pretoria |
Wingfield M.J.,University of Pretoria |
Wingfield B.D.,University of Pretoria |
Thu P.Q.,Vietnamese Academy of Forest science |
Barnes I.,University of Pretoria
Infection, Genetics and Evolution | Year: 2016
The fungal pathogen, Ceratocystis manginecans, has caused serious canker and wilt disease on Mangifera indica (mango), on legume tree species in Oman and Pakistan and on Acacia spp. in Indonesia. A Ceratocystis species, with similar morphology to C. manginecans, has recently been reported in Vietnam, causing severe disease of Acacia trees. Previous population genetic studies on isolates from M. indica in Oman and Pakistan have shown that the pathogen represents a single clonal haplotype, indicative of an introduced pathogen. The aim of this study was to investigate the genetic diversity and population structure of 160 C. manginecans isolates, from four host-associated populations from Oman, Pakistan, Indonesia and Vietnam. This was done by applying a combination of 14 previously developed microsatellite markers and a new set, designed in this study from two different C. manginecans genomes. Sequence data confirmed that the isolates in Vietnam are the same species as those in Indonesia and were thus identified as C. manginecans. Unlike the populations in Oman and Pakistan, relatively high levels of genetic variation were found for the isolates from Indonesia and Vietnam. The Vietnam population was significantly differentiated from the other populations and isolates from this area had the highest level of genetic diversity thus far encountered for the pathogen. © 2015 Elsevier B.V.
Tan D.T.,Vietnamese Academy of Forest science |
Thu P.Q.,Vietnamese Academy of Forest science |
Dell B.,Murdoch University
Forests | Year: 2012
The impact of invasive plant species in national parks and forests in Vietnam is undocumented and management plans have yet to be developed. Ten national parks, ranging from uncut to degraded forests located throughout Vietnam, were surveyed for invasive plant species. Transects were set up along roads, trails where local people access park areas, and also tracks through natural forest. Of 134 exotic weeds, 25 were classified as invasive species and the number of invasive species ranged from 8 to 15 per park. An assessment of the risk of invasive species was made for three national parks based on an invasive species assessment protocol. Examples of highly invasive species were Chromolaena odorata and Mimosa diplotricha in Cat Ba National Park (island evergreen secondary forest over limestone); Mimosa pigra, Panicum repens and Eichhornia crassipes in Tram Chim National Park (lowland wetland forest dominated by melaleuca); and C. odorata, Mikania micrantha and M. diplotricha in Son Tra Nature Conservation area (peninsula evergreen secondary forest). Strategies to monitor and manage invasive weeds in forests and national parks in Vietnam are outlined. © 2012 by the authors.
Wang B.,Umeå University |
Khalili Mahani M.,Kyushu University |
Ng W.L.,Kyushu University |
Kusumi J.,Kyushu University |
And 5 more authors.
Ecology and Evolution | Year: 2014
Pinus krempfii Lecomte is a morphologically and ecologically unique pine, endemic to Vietnam. It is regarded as vulnerable species with distribution limited to just two provinces: Khanh Hoa and Lam Dong. Although a few phylogenetic studies have included this species, almost nothing is known about its genetic features. In particular, there are no studies addressing the levels and patterns of genetic variation in natural populations of P. krempfii. In this study, we sampled 57 individuals from six natural populations of P. krempfii and analyzed their sequence variation in ten nuclear gene regions (approximately 9 kb) and 14 mitochondrial (mt) DNA regions (approximately 10 kb). We also analyzed variation at seven chloroplast (cp) microsatellite (SSR) loci. We found very low haplotype and nucleotide diversity at nuclear loci compared with other pine species. Furthermore, all investigated populations were monomorphic across all mitochondrial DNA (mtDNA) regions included in our study, which are polymorphic in other pine species. Population differentiation at nuclear loci was low (5.2%) but significant. However, structure analysis of nuclear loci did not detect genetically differentiated groups of populations. Approximate Bayesian computation (ABC) using nuclear sequence data and mismatch distribution analysis for cpSSR loci suggested recent expansion of the species. The implications of these findings for the management and conservation of P. krempfii genetic resources were discussed. © 2014 The Authors. Ecology and Evolution published by John Wiley & Sons Ltd.
Van Tho N.,Vietnamese Academy of Forest science |
Xia N.-H.,Chinese Academy of Sciences |
Lam L.V.,Ministry of Science and Technology
Novon | Year: 2014
A new species of Dendrocalamus Nees (Poaceae, Bambusoideae), D. longivaginatus N. H. Xia, V. T. Nguyen and V. L. Le, is illustrated and described from Phu Tho, Vietnam. This species is known only from the northern provinces of Vietnam: Phu Tho, Yen Bai, and Ha Giang. It is morphologically similar to D. brandisii (Munro) Kurz, a widely distributed bamboo from Thailand, Myanmar, China, and Vietnam, but differs by the ligules of the culm sheath, which are irregularly fimbriate, slightly concave, and 7-9 mm, and by the pseudo-spikelets, which are (5-)13-16 mm with lemmas 9-11.5 mm.
Nguyen H.N.,Vietnamese Academy of Forest Science |
Tran V.T.,University of Dalat
Annales Botanici Fennici | Year: 2014
A clambering bamboo from southern Vietnam is described as a new species, Maclurochloa locbacensis N.H. Nguyen & V.T. Tran (Poaceae, Bambusoideae) and illustrated in line drawings. It is similar to M. montana and M. tonkinensis, but differs by having deeply concave culm sheaths and flat stigmas. © Finnish Zoological and Botanical Publishing Board 2014.
Nguyen T.T.,University of Melbourne |
Nguyen T.T.,Vietnamese Academy of Forest Science |
Baker P.J.,University of Melbourne
Plant Ecology and Diversity | Year: 2016
Background: Deciduous dipterocarp forest (DDF) is the most widespread forest type of continental Southeast Asia. Four dominant canopy species of the DDF are often found in near-monodominant stands, but quantitative structure, species composition and regeneration status of these stands are little understood. Aims: To quantify structural, compositional and regeneration variability of the dominant stands in the DDF at YokDon National Park in Central Vietnam. Methods: We established seventy 0.04 ha plots across the Park to quantify the structure, species composition and regeneration patterns. Results: We found distinct patterns of one or two of the four dipterocarp species dominated basal area in any given stand. Patterns of seedling dominance were not as distinct as in the canopy, nor were there strong associations between the dominant seedling and canopy species, particularly for Shorea siamensis. The most striking feature of the forest was the absence of saplings, implying a significant bottleneck in the structure. Conclusions: Our results suggest a potential shift in the dominant canopy species in the DDF. The apparent lack of recruitment into the larger size classes and the decoupling of dominant species in the canopy and seedling layer raise questions about the future dynamics of the DDF. © 2016 Botanical Society of Scotland and Taylor & Francis
Nambiar E.K.S.,CSIRO |
Harwood C.E.,CSIRO |
Kien N.D.,Vietnamese Academy of Forest science
Southern Forests | Year: 2015
Vietnam has established 1.1 million ha of acacia plantations for wood production, managed on 5- to 10-year rotation cycles. Nearly 50% of the resource is managed by small growers holding 1–5 ha woodlots. Acacia plantations have emerged as an important resource for supporting the rural economy and national export revenue. Given the range of climate, terrain, soils, management inputs and skills, plantation productivity varies from 10 to 25 m3 ha−1 y−1. Future growth of this sector will depend on improving and sustaining production from the current land base, much of which is already in its second or third rotation. Although studies on sustainable production are limited, available information suggests good prospects for increasing production and improving soils. Breeding has produced genotypes with potential for increasing growth, but this has not generally been matched by sustainable soil and stand management practices. Several current practices warrant immediate change, based on sustainability principles. Internationally, research has established the need for conserving site resources and other judicious management practices. Vietnam should adopt these principles and develop locally appropriate practices to implement them. Greater efforts are required on surveillance of major diseases and tree breeding to improve disease resistance. Because acacia plantations deliver high economic benefits and there are opportunities for improving productivity, an R&D strategy focused on underpinning sustainable management and application would serve the nation well. Key elements include commitments to adaptive research for achieving impacts, effective partnerships between public and private organisations, fostering an integrated approach to management, and special attention to the needs of smallholder growers. © 2015, Copyright © NISC (Pty) Ltd.
Hai P.H.,Vietnamese Academy of Forest science |
Duong L.A.,Vietnamese Academy of Forest science |
Toan N.Q.,Forest Science Institute of Vietnam |
Ha T.T.T.,Forest Science Institute of Vietnam
New Forests | Year: 2015
164 open-pollinated families of Acacia mangium from six different genetic groups were tested in three second-generation progeny tests planted at Tuyen Quang and Ba Vi in northern Vietnam and Bau Bang in the south. All trees were measured to estimate individual heritabilities and genetic correlations for growth traits, stem straightness and pilodyn in the three trials, and dynamic modulus of elasticity (MoEd) of standing trees was only assessed in Tuyen Quang. There were significant differences between families for growth traits, stem straightness, pilodyn penetration and predicted MoEd. Heritabilities of growth traits, stem straightness, pilodyn and dynamic modulus of elasticity were low to moderate (h2 = 0.11–0.30). The coefficient of additive genetic variation for DBH, pilodyn and MoEd were moderate at age 3 or 4 years (CVa = 4.9–9.4 %). Genetic correlations between stem straightness, pilodyn and growth traits were favourable but weak, while those between growth traits and dynamic modulus of elasticity were weak and unfavourable. The substantial coefficients of additive genetic variation and significant heritabilities for all traits indicate that it should be possible to use a selection strategy that combines improvements in growth, stem straightness, and wood quality for A. mangium in Vietnam. The site–site genetic correlations between the two northern trials and Bau Bang site were low for growth traits, indicating that G × E effects are of practical importance for growth and different deployment populations will be required for different sites. © 2015, Springer Science+Business Media Dordrecht.