Taxonomic revision of Garcinia section Garcinia (Clusiaceae)

Species of Garcinia sect. Garcinia are typically understorey trees in rain forest and are distributed from eastern India to Malesia. A taxonomic revision of Garcinia section Garcinia (Clusiaceae) has resulted in the recognition of 13 species, two of which have three varieties each. Several species are excluded from Garcinia section Garcinia, reported as insufficiently known, or reduced to synonymy. Five species, G. acuticosta, G. discoidea, G. exigua, G. ochracea and G. sangudsangud, and two varieties, G. diospyrifolia var. minor and G. mangostana var. borneensis, are newly described. Morphological characters that are important for sectional delimitation are terminally attached inflorescences of simple cymes, stamen bundles 4 or 4-angled, and fruits with a smooth surface. Species limits are defined on the basis of a combination of characters of the male flower (i.e. shape of stamens, presence of pistillode), type of fruit, and characters of the leaf (shape and size, venation pattern and glandular lines)

Tree species diversity of logged over forest at Tekai Tembeling Forest Reserve, Jerantut, Pahang.

The quantitative assessment of the hill logged-over forest at Tekai Tembeling Forest Reserve (TTFR), Jerantut, Pahang, Malaysia has never been investigated by the Forestry Department in the State of Pahang. This study investigated tree species diversity at 340-520 m asl. A one-ha (100 m × 100 m) study plot was established and trees with diameter at breast height (dbh) of 5.0 cm and above were measured. Results showed that a total of 1307 trees from 241 species were recorded from this 1-ha plot. Shorea curtisii had the highest relative abundance (0.039) followed by Swintonia floribunda (0.038) and Knema sp.l (0.034). Jackknife method for species richness estimated that 324.2 species present in the 100 quadrats. The regression equation to estimate species richness was lnŜ=0.91+0.49 ln (A) with r2=0.99% Simpson's index of diversity was 0.99 and Shannon-Weiner diversity (FT) was 6.99. Results also showed that Simpson's measure of evenness was 0.35 and Smith and Wilson's index of evenness was 0.50. These results suggested that species richness and diversity in logged-over forest of TTFR was high but the evenness was low. This was mainly because the species abundance within this plot comprised a variety of species and less species overlapping

Assessment of plant species diversity at Pasir Tengkorak Forest Reserve, Langkawi Island, Malaysia

Plant species diversity of a logged-over coastal forest with in the Pasir Tengkorak Forest Reserve, Langkawi Island, Malaysia was assessed by establishing a 1-ha plot. All plants above 1.0 cm dbh (diameter of a tree at breast height), or 4.5 feet above ground level, the accepted point of diameter measurement for most trees were enumerated. Species diversity was defined as a combination of species richness and evenness. The jackknife estimate and species- area curve were applied to estimate the species richness. It was estimated using Simpson’s index of diversity, Shannon-Weiner function and Brillouin index. Simpson’s measure of evenness, Camargo’s index of evenness and Smith and Wilson’s index of evenness were also used to estimate species evenness. A total of 3414 individual trees representing 120 species, 81 genera and 31 families were recorded. Species with highest relative abundance were Swintonia sp1(0.12), Garcinia eugnifolia(0.09) and Syzygium sp1(0.05). The jackknife estimate of species richness was 132.9 and the regress ion equation to estimate species richness was LnSˆ=2.53 + 0.24 ln (A)with r2=96.0 %. Species diversity was high with Simpson’s index of diversity with a value of 0.96, while Shannon-Weiner index was 5.42 and Brillouin’s Index was 5.14. However, Simpson’s measure of evenness, Camargo’s index of evenness and Smith and Wilson’s index of evenness were 0.264, 0.378, and 0.41 9, respectively. Results indicated that species richness and species diversity were high, but evenness was low in this logged-over coastal forest

An assessment of genetic variation in vulnerable Borneo Ironwood Eusideroxylon zwageri Teijsm. & Binn. in Sarawak using SSR markers

Borneo Ironwood Eusideroxylon zwageri Teijsm. & Binn. has high market value for its valuable and durable tmber, which has put it at risk due to illegal logging. This study analyzed E. zwageri genetic variation using four microsatellite markers in populations at Nirwana Rehabilitation Forest (NRF), and Tatau, Sarawak. We found that 20.1% of total genetic variation corresponded to differences between populations, while 79.9% was attributed to differences among individuals from the same population. The Tatau population had lower genetic diversity compared to NRF, and both populations showed depressed heterozygosity indicative of inbreeding. Allelic data were also used to confirm variety level differences proposed by earlier workers, and three informal varieties: zwageri, grandis, and exilis were recognized in the study area. It is expected that the results from this study could serve as baseline data for conservation of this vulnerable species

The origin of cultivated mangosteen (Garcinia mangostana L. var. mangostana): Critical assessments and an evolutionary-ecological perspective

Mangosteen (Garcinia mangostana var. mangostana) is a popular tropical fruit, yet many aspects of its biology and evolutionary history are little known. Its origin remains contentious, although recent findings suggest G. mangostana L. var. malaccensis (Hook. f.) Nazre (synonym: G. malaccensis Hook. f.) as the sole progenitor. We review hypotheses on the origin of mangosteen and clarify points that have been affected by errors of fact and interpretation. The narrow focus and lack of detail in published results make their interpretation difficult. When possible, we support our interpretations with field observations and examination of herbarium specimens. We outline the main biological traits (e.g., dioecy, facultative apomixis, and polyploidy) of mangosteen and its wild relatives to infer traits that might have evolved during domestication of mangosteen. We find no clear indication that apomixis and polyploidy evolved during domestication. Polyploidy is known in the wild relatives, but apomixis has not yet been demonstrated. Also, we propose a testable new evolutionary-ecological framework that we call “Forest-Dusun Interface” to infer processes in the origin of mangosteen. Dusun (Malay) refers to subsistence orchards in this context. Lastly, we propose future studies to address identified knowledge gaps

Tree health status of mixed species in urban forest of Taman Rimba Alam, Putrajaya, Malaysia

Taman Rimba Alam (TRA), Putrajaya is a metropolitan recreational park with an area of 160 ha planted with various tropical forest species. Although TRA is a man-made forest, it serves and functions as any other natural forest especially for the well-being of people in urban area. In order to ensure that TRA could functions as it has been envisaged, tree health is one of major element that needed to be monitored. In forest plantation practises, tree health usually is measured by the growth performance (using diameter or height), and mortality rate within an area planted or among species group. However, Visual Tree Assessment (VTA) method established by the International of Arboriculture (ISA) could be applied to assess tree health for mixed species of planted trees such as in TRA. In order to do that, a study was carried out to assess the tree health in TRA by using the modified VTA method. A total of 644 trees from various species and sizes in TRA were selected and inspected. Results showed that most trees are in good health, but the status of health was different based on species and size of trees. The VTA method also showed that tree defects were mostly found in the crown part due to competition for space and light. Suitable maintenance particularly thinning programme should be done periodically to maintain tree health and reduce tree defects

Mangrove productivity estimation using modelling approach and tree parameters assessment

This study used productivity models and above ground biomass to investigate productivity in different sites of MMFR. Ninety Rhizophora apiculata leaf samples were collected from different compartments (18, 31, 71, 74, 42 and 55) based on tree age and management. For biomass calculation, tree height and diameter were measured in plot of 10m x 10m in compartment 18, 31, 71, 74 and 67. The age of the trees were as follows: compartment 18 and 31 with 15-year-old, compartment 71 and 74 with 25-year-old and compartment 67 with 30-year-old mangrove trees. Compartment 42 and 55 are classified as virgin jungle reserve (VJR). Compartment 67 was not taken as a sample site due to technical reason and compartments in VJR were not considered for biomass estimation. Sixteen variables; stable isotopes (δ13C, δ15N), macronutrients (C, N, P), cations (Ca, Mg, Na, K) and trace elements (Cd, Cu, Fe, Mn, Pb, Zn) were analyzed. Productivity models and calculated biomass for investigated compartments showed similar trends. In 15-year age group; compartment 18 showed higher productivity than in 31. For the 25-year age group; compartment 74 had higher productivity than 71. No prominent increase was observed in biomass between 15-year old and 30-year old trees. Furthermore, with moderate N and δ15N loading input, compartments showed more productivity. The results conclude that MMFR is a sustainably managed mangrove forest and its productivity could be monitored using nutrient productivity models

Pest and disease incidence of coniferous species in Taman Saujana Hijau, Putrajaya urban park, Malaysia

Taman Saujana Hijau (TSH), Putrajaya is a 41-ha urban park planted with various coniferous species from around the world. Insect pests and disease incidences of this park are unknown and there is a need for an evaluation of the health status of this urban park. This study assessed the level of pest and disease incidents of coniferous species in 12 plots of 7 species (Araucaria bidwilii, Araucaria haterophylla, Araucaria cunninghamii, Pinus caribaea, Pinus merkusii, Podocarpus polystachyus, and Podocarpus costalis). Termites, canker disease, and foliar disease are three major problems. The highest pest and disease incidence (PnDI) was foliar disease with a 0.49 coefficient correlation between the total number of trees and the PnDI, followed by canker disease with 0.40, and termites with 0.36. Of the seven conifers, A. haterophylla was the most infected followed by A. bidwilii and A.cunninghamii. It was concluded that the incidence of pests and diseases in TSH was moderate. To our knowledge, this may be the first baseline inventory of pests and diseases of coniferous species in Malaysia

Genetic structures across a biogeographical barrier reflect dispersal potential of four Southeast Asian mangrove plant species

Aim: Biogeographical barriers restrict the movement of individuals, resulting in population divergence, genetic differentiation, endemism and speciation. Yet, some barriers demonstrate unequal effect across species depending on species dispersal, which manifests in varying genetic structure. We test the hypotheses that the genetic structure of four coastal mangrove species would reflect differences in dispersal potential across the Malay Peninsula, a major biogeographical barrier in the Indo-West Pacific region. Location: East and west coasts of the Malay Peninsula. Taxon Mangrove trees Avicennia alba, Sonneratia alba, Bruguiera gymnorhiza and Rhizophora mucronata. Methods: For each species, we characterized genetic structure and gene flow using 7–12 species-specific nuclear microsatellite markers. We tested for east–west genetic differentiation across the peninsula, a stepping-stone migration pattern, and assessed the proportion of recent dispersal and direction of historical migration along the Malacca Strait. Results: Significant east–west genetic differentiation across the peninsula was observed in A. alba, S. alba and B. gymnorhiza, and the effect was most pronounced for the two species with lower dispersal potential (A. alba, S. alba). In contrast, the two species with higher dispersal potential (B. gymnorhiza and R. mucronata) exhibited much higher proportion of recent inter-population migration along the Malacca Strait. The signature of historical colonization from refugia in the Andaman Sea (north-to-south migration along the Malacca Strait) predominated for A. alba and S. alba. Historical south–north migration predominated for R. mucronata and B. gymnorhiza. Main conclusions: This study implicated dispersal potential as a cause of varying mangrove species genetic structure across a biogeographical barrier. The Malay Peninsula functions as a filter to gene flow rather than a barrier. The genetic structure in mangrove species with a higher dispersal potential is more congruent with contemporary gene flow while that of species with a lower dispersal potential reflects historical processes. Our findings hint at the role of dispersal potential as a predictor of gene flow in mangroves