Tree Population Structure Research Articles

Taxon-specific or universal? Using target capture to study the evolutionary history of rapid radiations.

Target capture has emerged as an important tool for phylogenetics and population genetics in nonmodel taxa. Whereas developing taxon‐specific capture probes requires sustained efforts, available universal kits may have a lower power to reconstruct relationships at shallow phylogenetic scales and within rapidly radiating clades. We present here a newly developed target capture set for Bromeliaceae, a large and ecologically diverse plant family with highly variable diversification rates. The set targets 1776 coding regions, including genes putatively involved in key innovations, with the aim to empower testing of a wide range of evolutionary hypotheses. We compare the relative power of this taxon‐specific set, Bromeliad1776, to the universal Angiosperms353 kit. The taxon‐specific set results in higher enrichment success across the entire family; however, the overall performance of both kits to reconstruct phylogenetic trees is relatively comparable, highlighting the vast potential of universal kits for resolving evolutionary relationships. For more detailed phylogenetic or population genetic analyses, for example the exploration of gene tree concordance, nucleotide diversity or population structure, the taxon‐specific capture set presents clear benefits. We discuss the potential lessons that this comparative study provides for future phylogenetic and population genetic investigations, in particular for the study of evolutionary radiations.

The Effects of Forest Management Activities on Genetic Diversity of Forest Trees

Genetic diversity helps to survive forest trees in several environmental changes and disease conditions. Different forest management activities such as harvesting, thinning, natural or artificial regeneration, seedlings or coppice forests, fragmentation, and overexploitation have a tremendous influence on the genetic diversity and population structure of forest trees. This paper aimed to review the impacts of these activities on the genetic diversity of forest trees. For this, we reviewed several scientific literature related to forest management practices that affect genetic diversity. Altogether,75 papers were reviewed, interpreted, and evaluated to prepare our final manuscript. The result of this study recommends that the level of genetic impacts varies with management activities, stand structure as well as species characteristics. There is very limited information about the impacts of forest management practices on the genetic diversity of forest trees since it is only focused on the growth of stands. The field research activities for species-specific must be executed considering ecological and reproductive parameters to assure sustainable forest ecosystems. Hence, this review will be beneficial for forest conservationists, researchers, and managers for the management of forests through better forest management activities preserving a genetic pool of the forest trees, and sustainable utilization of forest products.

Genome-Wide Association Studies Provide Insights into the Genetic Determination of Flower and Leaf Traits of Actinidia eriantha

Kiwifruit (Actinidia eriantha) is a dioecious vine, and the pollen of its male cultivars has a direct effect on the quality of its fruits. In this study, to facilitate molecular breeding and gene identification, we performed genome-wide association studies (GWAS) on 11 traits of flower and leaf. A total of 946,337 highly consistent SNP markers were obtained in the whole genome. Phylogenetic tree analysis and population structure analysis showed that the 143 germplasms can be divided into two groups. The linkage disequilibrium analysis showed that A. eriantha have a relatively fast attenuation rate, and that the average attenuation distance of LD was 0.1–0.3 Kb. The MLM (QK) model was determined as best for correlation analysis, and eight and three SNPs associated with flower- and leaf-related traits were identified, respectively, at 0.01 significance level. However, SNP markers associated with stamen number per flower, pollen viability, total chlorophyll content, and total flavonoid content were not identified at the 0.01 significant level, although it is worth noting that one, one, five, and two SNPs were identified to be associated with these traits at the 0.05 significant level. This study provides insights into the complex flower- and leaf-related biology, and identifies genes controlling important traits in A. eriantha through GWAS, which extends the genetic resources and basis for facilitating molecular breeding in kiwifruits.

Density, diversity and community composition of trees in tropical thorn forest, peninsular India

Tropical thorn forests (TTFs) are characterized by the presence of small and thorny trees which usually shed their leaves in dry season. A quantitative phytosociological study was conducted in Uthumalai Reserve Forest of Peninsular India to record density, species richness, diversity and population structure of trees. Diameter of all free standing trees ≥1 cm diameter at breast height (DBH, cm) was measured at 1.37 m above the ground. A sum of 4135 trees ≥1cm DBH recorded from one hectare study plot. With 2272 (54.94%) individuals Dalbergia spinosa dominated the study plot followed by Commiphora berryi (484, 11.70%), Grewia flavescens (259, 6.26%), Dichrostachys cinerea (206, 4.98%) and Anogeissus pendula (171, 4.14%). In total, 26 species belonged to 19 genera and 15 families found in one ha study plot. The family Mimosaceae had a large number of species followed by Apocynaceae, Capparidaceae, Tiliaceae, Rhamnaceae. Rubiaceae (each 2 species). Stand basal area of tree community recorded as 15.238 m2 ha-1. Commiphora berryi constituted 50.80% (7.74 m2 ha-1) of stand basal area followed by Dalbergia spinosa (19.43%, 2.96 m2 ha-1). The forest showed a reverse J shaped population structure. Shannon diversity (H), equitability (H’) and Simpson’s dominance (D) indices of study area recorded as 1.76, 0.54 and 0.335, respectively. Dalbergia spinosa, Commiphora berryi, Grewia flavescens, Dichrostachys cinerea and Anogeissus pendula topped the species important value index with 87.80, 73.53, 20, 19.79, 17.43 scores, respectively. In family important value index, Papilionaceae topped the list followed by Burseraceae and Mimosaceae with scores 129.32, 74.23 and 34.43, respectively. The study area endowed with a moderate species richness and diversity, and acts as one of the homes for an IUCN’s vulnerable tree species.

Tree population structure in fragments of different sizes in the Eastern Amazon

Tree population structure in fragments of different sizes in the Eastern Amazon

Tree Diversity, Stand Structure and Community Composition of Tropical Forest in Eastern Ghats of Tamil Nadu, India

rest of Eastern Ghats is degrading due to various anthropogenic pressures. In a present study to assess the tree diversity and population structure in the tropical forest of Javadhu hill Eastern Ghats, Tamil Nadu, India, total of 62 tree species belonging to 44 genera and 23 families and 5140 stems were enumerated in 10 ha plots. Memecylon umbellatum was the predominant tree species followed by Psydrax dicoccos, Chloroxylon swietenia and Anogeissus latifolia. The mean density was 514 stems ha -1 and the density of trees ranged from 469-623 ha -1 . The basal area in all the study plots ranged from 19.4 m 2 /ha to 33.2 m 2 /ha and the mean basal area for the 10 ha plots was 19.87 m 2 /ha. All top five species had greater density and basal area in 30-90 cm girth class. The Euphorbiaceae are taxonomically diverse and constituted the most-speciose family followed by Combretaceae. The species richness of deciduous species was greater followed by evergreen and brevi-deciduous. The present study reveals that the forest ecosystem restores considerable tree diversity here which is under more threat due to anthropogenic pressure. Therefore, immediate conservation measure is required to preserve the vanishing forest resources.

Genetic characterization of global collection of flax (L. Usitatissimum L.) utilizing molecular marker

In assess the sufficient knowledge of genetic diversity, population structure and linkage disequilibrium were estimated among the three representative sub-population: Pop 1 (Indian accessions), Pop 2 (different species of Linum genus) and Pop 3 (exotic accessions) of flax using ISSR marker systems. A total of 118 number of alleles were amplified by eleven primers, with an average of 10.64 alleles per primer (100 bp −2072 bp). The maximum PIC value (0.25) was observed in the primer combination UBC808, which indicated that it as the most informative primer among the eleven primers to study genetic diversity among flax genotypes. The results of the AMOVA indicated that genetic variation within sub-populations (92%) was significantly higher than the variation among the sub-population (8%). According to the results of split network tree analysis, population structure and PCA, the total 264 flax accessions were distinctly clustered into eight genetic groups. Overall the mean LD value was less than the threshold level (r2 < 0.1) explaining that the population has a high level of outcrossing or gene flow. The knowledge generated through ISSR fingerprinting in this study has enhanced our conception of population structure and LD of the flax population, which has high implications for genetic improvement and association mapping.

Anthropogenic Pressure on Tree Species Diversity, Composition, and Growth of Balanites aegyptiaca in Dinder Biosphere Reserve, Sudan.

Anthropogenic disturbances, such as illegal harvesting and livestock browsing, often affect natural forests. However, the resulting tree species diversity, composition, and population structure have rarely been quantified. We assessed tree species diversity and importance value indices and, in particular, Balanites aegyptiaca (L.) Del. population structure, across 100 sample plots of 25 m × 40 m in disturbed and non-disturbed sites at the Dinder Biosphere Reserve, Sudan, from April 2019 to April 2020. We found that the tree species diversity in non-disturbed sites was more than double that of disturbed sites (p < 0.001, T = 32.6), and seedlings and saplings comprised more than 72% of the entire tree population (F2,48 = 116.4, p = 0.034; F2,48 = 163.2, p = 0.021, respectively). The tree density of B. aegyptiaca in the disturbed site was less than half that of the non-disturbed site (p = 0.018, T = 2.6). Balanites aegyptiaca was seven times more aggregated in disturbed sites compared to more regularly spaced trees in non-disturbed sites (T = 39.3 and p < 0.001). The poor B. aegyptiaca population status of the disturbed site shows that the conservation of this vulnerable species is essential for a sustainable management and utilization scheme.

Development of microsatellite markers for Calyptranthes clusiifolia (Myrtaceae)

The endemic tree species Calyptranthes clusiifolia (Myrtaceae) plays a relevant ecological role in the forest fragments where it has a common occurrence. In this study, we reported the development of microsatellite markers for C. clusiifolia what will allow a better understanding of the relationship between the forest fragmentation process and the genetic structure and diversity of tree populations. Seven microsatellite markers were developed using an enriched genomic library and characterized in 30 individuals (from three populations). These seven loci were polymorphic and resulted in a total of 23 alleles. The expected heterozygosity (HE) varied from 0.14 (Caly 06) to 0.73 (Caly 22). Linkage disequilibrium between the loci (p > 0.0007) pairs was not detected. The parentage exclusion power of the first (Pe-1) and the second (Pe-2) parents were 0.6099 and 0.8548, respectively. The microsatellite markers developed are indicated for future studies of the genetic diversity in natural populations of C. clusiifolia.

Mass Mortality as a Way of Structuring Amazonian and Alpine Tree Populations: Evidence After Storm Vaia

Abstract By logging in the past, humans can determine current tree population structures, but fast stump decomposition makes difficult to falsify that for Amazonian Rainforests. We reconstructed land-use histories and surveyed trees ≥ 10 cm diameter at breast height on three 1-ha plots (K1, K2, and K6) in Kühbergl, South Tyrolean Alps as we did for four plots in Atacapi, Ecuador (plots A, B, C, and D). Storm Vaia (October 27 –November 1, 2018) stroke Kübergl providing dated evidence of mass tree-mortality on plot K6. We used K6 as control for comparing its pre- and post-storm population structures with the ones of four Amazonian, and three Alpine species where Vaia did not kill trees (Kolmogorov-Smirnov tests). When compared with K6’s Picea abies, the following species had size distributions similar to post-storm, but not to pre-storm situation. Amazonian: Piptocoma discolor, Vochysia bracelineae (plots B and D), Miconia decurrens (plots B and C), and Pseudobombax sp (plot C). Alpine: Larix decidua (plot K1) and Picea abies (plot K2). Storms do not occur in Atacapi, where logging is a common practice. That makes plausible that discrete events of compulsive logging during secondary succession made Amazonian population structures to look similar to K6’s P. abies. Logging is forbidden in Kühbergl, but storms are common there. Thus, the current population structures of Larix decidua (plot K1) and Picea abies (plot K2) should be legacies of storms before Vaia. Looking into tree populations’ history can impulse research for answering some basic questions of Ecology: what alters population structures, and which population structuring processes are more influential than others.

Impacts of harvesting intensity on tree taxonomic diversity, structural diversity, population structure, and stability in a West African mangrove forest

Understanding the impacts of wood harvesting intensity on the diversity and structure of ecosystems such as mangroves is essential for defining actions for their sustainable management. We compared tree taxonomic diversity, structural diversity and dominance patterns, density, growth characteristics, size class distribution-SCD and stand stability in West African mangroves subject to low vs. high wood harvesting intensity. Data on tree species identity, total height, diameter (dbh), and conditions (logged, topped or pruned) were collected from ten mangrove sites per harvesting intensity. We found seven species of which two true mangroves species (Rhizophora racemosa and Avicennia germinans) that were dominant across all sites. As expected, there were significantly 3–4, 3–7, and 2–4 times more logged, topped and pruned trees respectively in high-harvesting sites than in low-harvesting sites. Taxonomic diversity was less affected than structural diversity (dbh and height-based diversity metrics). Tree density was significantly 1.3–5 times higher in low-harvesting sites than in high-harvesting sites for the whole stand and each of the dominant species. Total regeneration density was also low in high-harvesting sites. However, regeneration density was relatively higher in high-harvesting sites for R. racemosa contrary to A. germinans. Trees were also significantly smaller and shorter in high-harvesting sites. The SCD indicated inverse J-shaped distributions, irrespective of the harvesting intensity and showed that tree harvesting targeted mostly dbh classes 10–30 cm. The density of this class was 2.6–6.2 times lower in high-harvesting sites. This study provides important information on impacts of wood harvesting in a marginally studied mangroves’ area.

长白山次生杨桦林种群空间点格局及密度制约效应

以长白山5.2 hm²次生杨桦林样地为研究对象，利用空间点格局分析的双相关函数g（r）以及随机标签零模型和案例-对照设计法，探讨了树木种群空间格局及其密度制约效应。研究结果表明：生境异质性对不同生活型以及不同树种的成熟个体在大尺度范围上具有强烈影响。剔除生境异质性带来的影响后，在14个常见树种中有12个树种在小尺度上呈显著的空间聚集分布格局；随着空间尺度的增加聚集性分布树种数量急剧下降，在18 m尺度上聚集率下降到0。全部14个常见树种均呈现出显著的密度制约效应，表明密度制约是调节温带森林树木种群空间结构的主要作用机制。此外，密度制约与物种多度呈负相关，与亚林层和灌木层树种的同种聚集强度呈正相关。并且随着空间尺度增大受密度制约影响的树种百分比逐渐减小，14个常见树种中有11个在0-1 m处达到最大的密度制约强度。;Taking 5.2 hm² secondary poplar-birch forest plot in Changbai Mountains as the research object, the pair-correlation function g(r) of the spatial point pattern analysis and the random label null model and case-control design method were used to discuss the spatial pattern of tree populations and its density dependence effect. The results showed that the L(r) function is more suitable for analyzing whether there is habitat heterogeneity in a research plot. Habitat heterogeneity had a strong impact on mature individuals with different life forms and different tree species on a large scale. This showed that when studying the spatial pattern, the impact of habitat heterogeneity on the research results should be fully considered. After excluding the impact of habitat heterogeneity, 12 of the 14 common tree species showed the significantly spatial aggregation distribution pattern on a small scale. With the increasing of spatial scale, the number of aggregated distribution tree species decreased sharply, and the aggregation rate dropped to 0 on the 18 m scale. The 14 common tree species all exhibited significant density dependence effects, indicating that density dependence was the main mechanism for regulating the spatial structure of temperate forest tree populations. In addition, density dependence was negatively correlated with species abundance and positively correlated with the same species aggregation intensity of sub-forest and shrub layer species. And with the increasing of spatial scale, the percentage of tree species affected by density dependence gradually decreased, and 11 of 14 common tree species reached the maximum density dependence intensity at 0-1 m.

A global framework for linking alpine‐treeline ecotone patterns to underlying processes

Globally, treeline ecotones vary from abrupt lines to extended zones of increasingly small, stunted and/or dispersed trees. These spatial patterns contain information about the processes that control treeline dynamics. Describing these patterns consistently along ecologically meaningful dimensions is needed for generalizing hypotheses and knowledge about controlling processes and expected treeline shifts globally. However, existing spatial categorizations of treelines are very loosely defined, leading to ambiguities in their use and interpretation. To help better understand treeline‐forming processes, we present a new framework for describing alpine treeline ecotones, focusing on hillside‐scale patterns, using pattern dimensions with distinct indicative values: 1) the spatial pattern in the x‐y plane: a) decline in tree cover, and b) change in the level of clustering. Variation along these dimensions results in more or less ‘discrete' or ‘diffuse' treelines with or without islands. These patterns mainly indicate demographic processes: establishment and mortality. 2) Changes in tree stature: a) decline in tree height, and b) change in tree shape. Variation along these dimensions results in more or less ‘abrupt' or ‘gradual' treelines with or without the formation of environmental krummholz. These patterns mainly indicate growth and dieback processes.Additionally, tree population structure can help distinguish alternative hypotheses about pattern formation, while analysing the functional composition of the ecotonal vegetation is essential to understand community‐level processes, controlled by species‐specific demographic processes.Our graphical representation of this framework can be used to place any treeline pattern in the proposed multi‐dimensional space to guide hypotheses on underlying processes and associated dynamics. To quantify the dimensions and facilitate comparative research, we advocate a joint effort in gathering and analysing spatial patterns from treelines globally. The improved recognition of treeline patterns should allow more effective comparative research and monitoring and advance our understanding of treeline‐forming processes and vegetation dynamics in response to climate warming.

Modeling tree diameters using mixtures of skewed Student’s t and related distributions

The size structure of tree populations making up a forest stand provides a scientific basis for evaluating the forest resources and scheduling future silviculture treatments. We evaluated the efficiency of the skewed Student’s t (ST) model to predict the distributions of various complex diameter at breast height (DBH) data. The ST model was compared with finite mixtures of selected functions (gamma, log-normal, and Weibull). Additionally, two scenarios were employed to determine the number of components: (1) the use of the Bayesian information criterion and (2) visual analysis of the histogram of the DBH relative frequencies. The ST model demonstrated the highest degree of flexibility for fitting the DBH distributions. It outperformed other competitors in modeling the DBH variables in terms of all implemented scenarios. It possesses a high degree of flexibility. This model should be used to fit the DBH distributions of multigeneration forest patches with diverse size structures.

Intraspecific variation in tree growth responses to neighbourhood composition and seasonal drought in a tropical forest

Abstract Functional traits are expected to provide insights into the abiotic and biotic drivers of plant demography. However, successfully linking traits to plant demographic performance likely requires the consideration of important contextual and individual‐level information that is often ignored in trait‐based ecology. Here, we modelled 8 years of growth from 1,138 individual trees in 36 tropical rain forest species. We compared models of tree growth parameterized using individual‐level versus species mean trait data. We also compared models that considered regional climatic, local biotic and whole‐plant allocation contexts to those that do not. Our analyses show that growth models parameterized using individual‐level trait information outperformed those that used species mean trait information and that these models often contradicted one another indicating that the common practice of using species mean trait data requires more scrutiny. Additionally, we found that models including climatic, biotic and allocation contexts outperformed those that did not and provided nuanced insights into the drivers of tree growth in a tropical forest. Synthesis. Here we have shown that the development of models of tree demographic performance upon the basis of traits can be improved through a consideration of individual‐level trait variation as well as phenotypic and climatic contexts. We highlight that our ability to understand the drivers of tree population and community structure and dynamics in current and in future climates will be limited if contextual and individual‐level data remains understudied.

Density and Population Structure of Globally Vulnerable and Endangered Trees in Chennai Metropolitan City, India

A quantitative floristic study was conducted in Chennai metropolitan city (CMC), Tamil Nadu, India to estimate density and population structure of trees categorized as vulnerable and endangered by International Union for Conservation of Nature and Natural Resources (IUCN) red-list. A total of one hundred 1–ha (100 m × 100 m) square plots were randomly laid to estimate density and species richness of threatened trees in study area. All trees ≥ 10 cm girth at breast height (gbh) were recorded, and identified up to species level on the field with the aid of regional floras and checklists. Six different land uses were recognised. In total, 10426 trees belonging to 99 species, 36 families and 86 genera were recorded. Of six land use categories, riverbanks had highest tree density (150.08 ± 21.02 trees ha-1) followed by parks (138.86 ± 29.08 trees ha-1) and institutional areas (98.77 ± 4.48 trees ha-1). In total, 1272 IUCN red-listed trees belonged to six families and eight genera were enumerated. Among land uses, educational institutions had largest number of threatened trees (374 individuals) followed by parks (327 individuals) and residential areas (228 individuals). We find Chennai's urban forests as home for seven vulnerable and three endangered tree species. This study reveals density and population structure of threatened trees growing in CMC, India.

Species diversity, population structure, and regeneration status of trees in Fakim Wildlife Sanctuary, Nagaland, Northeast India

Abstract. Ao A, Changkija S, Tripathi SK. 2020. Species diversity, population structure, and regeneration status of trees in Fakim Wildlife Sanctuary, Nagaland, Northeast India. Biodiversitas 21: 2777-2785. The plant species composition and diversity represent the overall health of the forest ecosystems and provide useful insight on forest conservation, and the species regeneration is important in assessing the potential of the forests to serve the society on sustained basis. This present study aimed to assess the species diversity, population structure, and regeneration status of the trees in temperate forest of Fakim Wildlife Sanctuary, Nagaland, Northeast India. Tree species composition, population structure and regeneration status were analyzed by randomly establishing eight plots of 0.1 ha within the sanctuary. Density, basal area, abundance, evenness, and other diversity indices were calculated for mature trees with girth at breast height (GBH) ≥ 30 cm. A total of 60 tree species belonging to 40 genera and 27 families were recorded. The most dominant families recorded were Lauraceae and Rosaceae. The total tree density recorded from the forest was 432.5 individuals ha-1 with a basal area 42.8 m2 ha-1. Cinnamomum zeylanicum and Lithocarpus pachyphyllus had the highest density with 17.58 individuals ha-1 and Lithocarpus pachyphyllus had the highest basal area with 2.64 m2 ha-1. The species with the highest IVI was Betula alnoides (17.13). Girth class of 30-60 cm had the highest density and basal area with 280 individuals ha-1 and 20.7 m2 ha-1. The diversity indices such as Shannon-Wiener index, Simpson index, Pielou evenness index, and Margalef species richness index were 3.90, 0.93, 0.92, and 11.59, respectively in the wildlife sanctuary. The present study showed that 41% of tree species exhibited good regeneration status, 31% as fair regeneration, 8% as poor regeneration and 20% had no regeneration. The present data will be useful to understand the current status of tree species and will serve as baseline information to the forest department, policymakers and conservationists to develop management plans for the conservation of priority species in the area.

M-Link: a link clustering memetic algorithm for overlapping community detection

Graphs and networks are a useful abstraction to represent a wide range of systems. Sets of nodes that are more highly interconnected constitute a ‘community’. Community detection algorithms help to reveal a decomposition of a network in modules. These communities can overlap, and nodes can have several community memberships. We present M-Link, a memetic algorithm for overlapping community detection. It maximises an objective function called link partition density. The communities of edges obtained with this method naturally translate to overlapping communities of nodes. The method is based on local expansion and a specialised local search mechanism. Label propagation methods are used for initialising a multi-agent tertiary tree population structure. We use the normalised mutual information to evaluate the similarity between the known community structure in a collection of benchmark networks and the community structure detected by M-Link. The method outperforms other state-of-the-art algorithms for overlapping community detection and it has better accuracy and stability.

Prospect of natural regeneration of tree species in Hazarikhil Wildlife Sanctuary of Chattogram, Bangladesh

Natural regeneration of tree species is the major means of understanding the restoration potentiality of a secondary forest. Natural regeneration of a forest is a tool for measuring the health of the forest ecosystem. Natural regeneration status of tree species in Hazarikhil Wildlife Sanctuary (HWS) in Chittagong North Forest Division, Bangladesh was assessed laying 75 systematic quadrats of 4m×4m in size. A total of 90 regenerating tree species belonging to 34 families was identified from the HWS. Euphorbiaceae family possessed maximum regenerating tree species (14 species) followed by Mimosaceae (7), Lauraceae and Meliaceae (6 species each), and Moraceae (5 species). The overall seedling density was 7,083 per ha where Ficus hispida showed the highest number of seedlings (792 per ha) followed by Quercus sp. (475), Ficus religiosa (408), Lithocarpus elegans (375) and Lepisanthes rubiginosa (367). The number of Ficus hispida seedlings per ha was higher due to high coppicing ability. Lepisanthes rubiginosa attained maximum IVI (27.59) followed by Ficus hispida (21.18) and Quercus oxyodon (13.32). The seedlings of Aegle marmelos, Lithocarpus sp., Flacourtia jangomas, Albizia odoratissima, Acronychia padunculata, Chaetocarpus castanicarpus, Maesa paniculata, Crypteronia paniculata, Streblus asper and Mussaenda roxburghii were also found common in the study area. The findings will create baseline information of regenerating tree species, composition, diversity and population structure which can be used for monitoring future changes as well as taking policy decisions for the management of this Wildlife Sanctuary.&#x0D; J. Biodivers. Conserv. Bioresour. Manag. 2019, 5(2): 1-12

Comparative Study on Tree Diversity and Population Structure in Two Forest Types of Nagaland, India

A study was carried out to investigate the population structure and tree species diversity in two different forest types of Nagaland. A total of 40 and 48 quadrats were plotted randomly in subtropical semi evergreen (SSE) and tropical wet evergreen (TWE) forest, respectively; and trees having > 10 cm girth at breast height were measured. Maximum 38 tree species belonging to 25 families in SEE and 30 species belonging to 24 families were recorded in TWE forest. Both the forest types were dominated by the tree species belonging to the Meliaceae family. A total of 613 individuals/ha with 1728.23 m2 basal area were recorded in TWE forest as compared to the 512 individuals/ha with 2363.88 m2 basal area in SSE forest. Shannon and Simpson diversity indices varied from 3.27–2.69 and 0.05–0.10, respectively. Moreover, 30–60 cm girth class showed higher number of individuals followed by 60–90 cm class. Tectona grandis, Gmelina arborea and Duabanga grandiflora were the dominant species in SSE, while TWE was dominated by Gmelina arborea and Grevillea robusta. The present study provides baseline data on population structure and diversity of trees in two forest types of Nagaland.