Structure and regeneration status of Komto Afromontane moist forest, East Wollega Zone, west Ethiopia

We conducted a study in Komto Forest in East Wollega Zone, Oromia National Regional State, West Ethiopia for determining vegetation structure and regeneration status in this forest. We systematically sampled 53 quadrats (20 m × 20 m) along line transects radiating from the peak of Komto Mountain in eight directions. Vegetation parameters such as DBH, height, seedling and sapling density of woody species, and location and altitude of each quadrat were recorded. In total, 103 woody plant species of 87 genera and 45 families were identified. Analysis of selected tree species revealed different population structures. Generally, the forest was dominated by small trees and shrubs characteristic of secondary regeneration. Observations on the regeneration of the forest indicated that there are woody species that require urgent conservation measures. Based on the results of this study, we recommend detailed ecological studies of various environmental factors such as soil type and properties, and ethnobotanical studies to explore indigenous knowledge on uses of plants.     

Floristic diversity and composition of the Biteyu forest in the Gurage mountain chain (Ethiopia): implications for forest conservation

The Afromontane forests of Ethiopia have been under a serious degradation threat. Assessment of floristic diversity and species composition in Biteyu forest of Gurage mountain chain in the central Ethiopia was conducted to examine the pattern of forest structure. Thirty plots of 30 m×30 m were used to record the vegetation and environmental data using systematic sampling technique. The local name, plant scientific names, DBH, height,species abundance and percentage canopy cover of plant species were recorded. Shannon diversity index and Sorensen's coefficients was used for comparison among communities and similar forests in the country. Threats to the forest biodiversity in Biteyu were determined by counting cattle interference and wood stumps as disturbance indicators. Relative Euclidean Distance measures by using Ward's method(linkage) was applied for cluster analysis. Environmental variables were also recorded in each plot. Woody species population structure, basal area and importance value index were analyzed using spreadsheet programs. Data on species distribution and environmental variables in the forest were analyzed by canonical correspondence analysis. A total of 190 species in 154 genera under 73 families were identified. Twenty species were found to be endemic taxa to the Flora Area. Only three plant community types were identified from the cluster analysis due to the high human influence. The Sorensen's coefficient showed the resemblance of the Biteyu forest with other Dry Evergreen Afromontane forests in the country. Moreover, altitude and slope strongly affect the species composition and structure of Biteyu forest. Given the high anthropogenic influence, high endemism, high dependence of the local community on the forest resources, forest conservation and restoration measures should be done by stakeholders.     

Floristic diversity and regeneration status of woody plants in Zengena Forest,a remnant montane forest patch in northwestern Ethiopia

The study was conducted at Zengena forest, a fragmented remnant montane forest in northwestern Ethiopia, which surrounds Lake Zengena. The purpose was to assess the species composition, diversity and the regeneration status of woody plants. A total of 27 plots of 20 m × 20 m were sampled along the line transects laid down the altitudinal gradient from the edge of the forest encompassing the lake to the edge of the lake in eight aspects. In each plot, woody species were counted and the diameter at breast height and the height of trees and shrubs were measured. A total of 50 woody species belonging to 31 families were found, of which 17(34%) were trees, 7(14%) trees or shrubs, 23(46%) shrubs and 3(6%) lianas. The overall Shannon-Wiener diversity and evenness indices of woody species were 2.74 and 0.7, respectively. Clausena anisata had the highest relative density(23.5%), Rapanea rhododendroides the highest relative frequency(6.5%) and Prunus africana the highest relative dominance(45%) and importance value index(IVI, 51.6). The total basal area and density of woody plants were 22.3 m2?ha-1 and 2,202 individuals?ha-1, respectively. The population structure showed variations among woody plants and revealed varied regeneration patterns of different species. The importance value index and population structure revealed that some species are threatened and need prioritization for conservation measures. The results suggest that remnant forest patches in the highlands of northern Ethiopia host several woody plant species that are almost disappearing in other areas due to deforestation.     

Floristic diversity, regeneration status, and vegetation structure of woodlands in Metema Area, Amhara National Regional State, Northwestern Ethiopia

We studied woodland vegetation in broad-leaved deciduous woodlands of Metema in northwestern Amhara regional state, Ethiopia Our objective was to describe plant species composition, diversity, regeneration status, and population structure by a selective approach with asystematic sampling design. A total of 74 quadrats (each for 25 m × 25 m,spaced at intervals of 150 200 m) were sampled along established transect lines following the homogeneity of the vegetation. Vegetation data including cover-abundance, height, diameter at breast height (DBH), and numbers of seedlings and saplings of woody species were analyzed using Excel spreadsheet, Shannon Weiner diversity index, and PAST version 1.62. A total of 87 vascular plant species of 74 genera and 36 families were recorded. The dominant family was Fabaceae represented by 16(18.39 %) species of 13 genera. Shannon Weiner diversity and evenness were 3.67 and 0.82, respectively, which showed that the area was endowed with rich floral diversity evenly distributed. The vegetation structure, as quantified by cumulative diameter class frequency distribution,plotted as an interrupted inverted-J-shape pattern with a sharp decreasein the 2nd diameter class. This indicated poor vegetation structure. The diameter classes frequency distributions of selected species plotted infour general patterns i.e., interrupted Inverted-J-shape, J-shape,Bell-shape and Irregular-shape. In conclusion, although the area showedhigh floral diversity and evenness, woody species including Sterculea setigera, Boswellia papyrifera, and Pterocarpus lucens showed lowest recruitment of seedlings and saplings.     

Comparison of ecological condition and conservation status of English yew population in two Austrian gene conservation forests

English yew Taxus baccata L. has been catalogued as endangered tree species and prone to extinction in Austria as well as many other parts of Europe. The present work is based on the comparison of the natural population of two gene conservation forests from different geographic locations in Austria where the spatial structure, regeneration status and possible conservation measures are examined. The pole stand distribution varied distinctly in each sites. The total no of individuals per ha （DBH ≥5 cm）, average DBH and average height were 492 n.hm^-2, 8.8 cm and 6.3 m in Stiwollgraben whereas in Leininger Riese 45 n.hm^-2, 16.3 cm and 7.6 m respectively. Over 79% of the Stiwollgraben population were represented the good health condition, while in Leininger Riese it was less then 49 % which means population of Stiwollgraben is in better condition compared to Leininger Riese. The sites differed considerably in the pattern of regeneration but pattern were consistent with the dynamics depicted by the age distribution. Considering the one-year-old seedlings Stiwollgraben contains 13 019 individuals.hm^-2 whereas Leininger Riese only 1 368. Surprisingly there were no any saplings in respect of 51 to 150 cm height classes in both sites and 30 to 50 cm in Stiwollgraben. In that context the conservation of English yew on the forest level may require well-managed reserves and long-term rotations between harvest events, protection from the herbivore and reduction of competition, which will enhance the long-term viability of the species.     

Effect of exclosure on dryland woody species restoration in northeastern Amhara,Ethiopia

In Ethiopia,among many restoration efforts to reverse deforestation and land degradation,area exclosure is one of the most common practices to restore secondary forests with assisted natural regeneration.The present study in the S ekota district,northeastern Amhara region,Ethiopia evaluated the influence of areas exclosures on woody species diversity,population structure and regeneration status.A total of 36 and 27 quadrats,each 20 m×20 m,were used to collect data in exclosures and non-exclosures,respectively.Within quadrats,four 5 m×5 m and 2 m×2 m quadrats at the corners were used to sample saplings and seedlings,respectively.In exclosures,35 woody species representing21 families and 29 genera were recorded;19 woody species representing 13 families and 13 genera were recorded in the non-exclosure.Acacia etbaica was the most dominant species in the two land-uses.The Shannon diversity index was1.77 ±0.46 in exclosures and 1.39±0.46 in non-exclosures.Shannon and Simpson diversity indices showed a significant difference between the two land-uses(p0.01).The regeneration status of all wood species in exclosures was good,only fair in non-exclosures.Area exclosures have thus played a great role in the restoration of degraded lands by improving vegetation diversity and regeneration status.The least dominant woody species should be maintained through active restoration.Continuous follow-up,maintenance of soil water conservation structure to improve soil fertility will further help enhance the woody species diversity and abundance.     

Species diversity,population structure and regeneration of woody species in fallows and mature stands of tropical woodlands of southeast Angola

This study in the dry tropical woodlands of SE Angola in Cuando-Cubango Province assessed the diversity and composition of woody species in fallows compared to those in mature woodlands. We assessed the population structure of the most harvested woody species by calculating size class distribution and evaluated their regeneration potential based on the density of saplings. The vegetation was surveyed in 20 plots of 20 × 50 m(1000 m2). In each plot, we measured the diameter at breast height(DBH) of all woody species with DBH ≥ 5 cm. The saplings were counted, identified and recorded; 718 individuals, corresponding to 34 species in 32 genera and 15 families were recorded. The size class distribution of target woody species showed three different patterns in fallows and mature woodlands. In general,most of the smaller diameter classes had more individuals than the larger ones did, showing that the regeneration may take place. However, in some diameter classes, the absence of larger stems indicated selective logging of larger trees. Few saplings were recorded in the fallows or mature woodlands; fire frequency and intensity is probably the main obstacle for seed germination and seedling survival rates in the studied area.     

Diversity and regeneration status of woody species in Tara Gedam and Abebaye forests,northwestern Ethiopia

A study was conducted in Tara Gedam and Abebaye forests l,northwestern Ethiopia to investigate the diversity,regeneration status,socio-economic importance and the factors causing destruction of the forests.A total of 30 plots,measuring 20 m ×20 m,were established along line transects laid across the forests.Participatory Rural Appraisal (PRA) method was employed to generate the socio-economic data.Primary data were collected by field observation,semi-structured interview with key informants and discussion with relevant stakeholders.A total of 143 woody species belonging to 114 genera and 57 families were recorded,and of all the species 44 (30.8%) were trees,57 (39.9%) trees/shrubs,33 (23.1%) shrubs and 9 (6.3%) lianas.The diversity and evenness of woody species in Tara Gedam forest are 2.98 and 0.65,respectively,and in Abebaye forest they are 1.31 and 0.31,respectively.The total density and basal area of woody species in Tara Gedam forest are 3001 individuals ha-1 and 115.36 m 2 ha-1,respectively,and in Abebaye forest the values are 2850 individuals ha-1 and 49.45 m 2 ha-1,respectively.The results on the importance value index (IVI) and DBH class distributions suggest that the species with low IVI value and poor regeneration status need to be prioritized for conservation.In the socio-economic survey,the responses from the key informants indicatedthat the forests are the major sources of fuelwood (90%),construction material (80%),timber (75%) and farm implements (55%).The forests are also sources of medicines,animal fodder,bee forage and edible fruits.Tara Gedam monastery,assisted by the local people who have strong religious belief and high respect to the monastery,has played a great role in the maintenance of the sacred forest since a long time.At present,the conservation efforts are made jointly by the monastery and institutions concerned with conservation.The major factors that cause destruction of the forests are livestock grazing,tree cutting for various purposes and farmland expansion.The implications of the results are discussed,and the recommendations are suggested for conservation,management and sustainable utilization of the forest ecosystems.     

Species diversity,regeneration and dominance as influenced by canopy gaps and their characteristics in tropical evergreen forests of Western Ghats,India

Canopy gaps play a significant role in maintaining structure and composition of tropical forests. This study was carried out in tropical evergreen forests of central Western Ghats in India to understand the influence of canopy gap size and the relationship of gap regime attributes to diversity measures and regeneration. The average gap size in the study area was found to be 396 m2 and around half of gaps were 4–8 years old. Gaps created by natural single tree fall were smaller in size but significantly higher in number. Diversity and regeneration of woody species were compared with canopy gaps and intact vegetation. Species richness and diversity was higher in gaps than in intact vegetation. Macaranga peltata, a shade intolerant species dominated gaps while intact vegetation was dominated by shade tolerant Kingiodendron pinnatum.Gap size significantly influenced species diversity and regeneration. Gap area and age were significantly and negatively correlated with diversity measures but positively correlated with regeneration. Among all the attributes of gaps, regeneration was significantly positively correlated with light intensity. Gaps maintained species diversity and favored regeneration of woody species. In addition to gap size and age, other gap ecological attributes also affected species diversity and regeneration.     

Woody plant diversity,structure and regeneration in the Ambo State Forest,South Gondar Zone,Northwest Ethiopia

For this study in the Ambo State Forest on woody plant diversity, structure and regeneration, 70 quadrats, each 25 m by 25 m, were selected using a systematic random sampling technique and intervals of 100 m along a transect line. For assessing seedlings and saplings,two 2 × 10 m sub quadrats were set upon opposite sides of each main quadrat. Data on species diversity, abundance,structure, basal area, density, frequency and regeneration status were collected and analyzed using standard procedures and programs. Of 58 woody plant species identified,69 % were trees, 16 % were shrubs, 12 % were tree/shrubs and 4 % were climbers. Fabaceae was the most speciesrich family comprising 17 species. The Shannon–Weiner diversity index was 2.73, and evenness was 0.67. The population structure in the cumulative diameter class frequency distribution revealed an interrupted and inverted J-shape with a very high decrease in higher diameter class.Acacia lahai(49 %) was the most important woody species with the highest importance value index. To maintain balanced structure, enhanced regeneration and protecting the forest from selective cutting are recommended.     

Floristic composition and ecological gradient analyses of the Liakot Forests in the Kalam region of District Swat,Pakistan

Kalam Kohistan is a dry,temperate hilly region in the Hindu Raj Series of the Greater Hindu Kush Mountains with diverse forests.As plant distribution and composition is expression of a range of various environmental variables,ecological and floristic attributes of vegetation in the Laikot Forests were therefore evaluated via consecutive explorative trips.These forests have not been evaluated ecologically before due to harsh climatic conditions and issues of accessibility and the study in hand is one of the first in its nature.Quantitative ecological techniques were used to sample forest vegetation and identify species in quadrats of 2 m×2 m for herbs,5 m×5 m for shrubs and 10 m×10 m for trees.All the data of 195 plant species and environmental factors were analyzed via Two-way Cluster Analysis and Canonical Correspondence Analysis using PCORD and CANOCO software.Among 195 plant species from 63 families were 27 species of Asteraceae,the most-speciose family,followed by Poaceae(20 spp.).The dominant life form was therophyte(86 spp.;44%share),followed by phanerophyte(41 spp.;21%share).For the leaf size spectrum,most prevalent was nanophyll(73 spp.;44%)followed by microphyll(66 spp.,34%)and mesophyll(44 spp.;23%).Calcium carbonate,pH,potassium,sand,silt,organic matter,slope aspect and grazing significantly influenced species composition,distribution and habitat.The floristic variation in the region was diverse due to elevational and aspect gradients and thus devided into three zones.This vegetation zonation can be utilized for forest management,species and habitat conservation.Both in situ and ex situ conservation of threatened plant species may improve their conservation status in future if address properly.     

Effects of gaps on regeneration of woody plants: a meta-analysis

Forest gaps, openings in the canopy caused by death of one or more trees, have a profound effect on forest regeneration and drive the forest growth cycle. It is therefore necessary to understand the effects of forest gaps on regeneration for modern forest management. In order to provide a quantitative assessment of the effects of forest gaps on regen-eration of woody plants, we conducted this review of gap effects on woody plant regeneration on the basis of 527 observations from 42 indi-vidual papers, and reported the results of these data in a meta-analysis. Overall, densities of regenerated woody plants were significantly greater （359%） in forest gaps than on the closed-canopy forest floor. The regen-eration density in gaps of plantation forests was significantly greater （P＆lt;0.05） than that of natural forest because the regeneration in gaps of plan-tation forests was improved by both gap effects and experimental meas-ures. Similarly, in comparison to natural gaps, regeneration was better enhanced in artificial gaps. Regeneration density exhibited a significantly positive correlation with gap size, but a negative correlation with gap age because the gap size decreased with increasing gap age. Shade tolerance of woody plants affected regeneration density in gaps and understory. Average regeneration density of shade-tolerant species exhibited a sig-nificantly positive response to gaps but densities remained lower in total than those of intermediate and shade-intolerant species. Gap effects on regeneration decreased in response to increasing temperature and pre-cipitation because of the limiting effects of lower temperature and moisture on woody plant regeneration. In summary, forest gaps enhance woody plant regeneration, and the effects of gaps varied by forest type, gap characteristics, environmental factors and plant traits. The results of this meta-analysis are useful for better understanding the effects and roles of gaps on forest regeneration and forest management.     

Diversity and structural composition of species in dipterocarp forests: a study from Fasiakhali Wildlife Sanctuary,Bangladesh

Fasiakhali Wildlife Sanctuary is a protected area composed of tropical remnant rainforest that harbor substantial number of large,old Garjan(Dipterocarpus spp.)trees.The present study assessed composition,structure and diversity of the species in this protected area.A total of 32 trees species were recorded with DBH ≥ 11 cm belonging to 24 genera and 19 families.The forest is low in plant diversity as represented by Shannon–Wiener diversity and Simpson Dominance indices.Dipterocarpus turbinatus was the most dominant species with maximum relative density,frequency,dominance,and importance value index.Syzygium firmum and Tectona grandis followed in terms of dominance.The structural composition indicated higher number of individuals in the medium growth classes(41 to 511 cm DBH and 16–20 m height ranges),whereas D.turbinatus was the only species that dominated most of the growth classes.Poor stem density in lower growth classes indicated meager recruitment of regeneration which may be due to lower annual precipitation,increased grazing and encroachments.This study will help to understand the patterns of tree species composition and diversity in the remnant dipterocarp forests of Bangladesh.It will also contribute to identifying threatened plants to undertake D.turbinatus based conservation and sustainable management of the Fasiakhali Wildlife Sanctuary.     

Effects of grazing on natural regeneration of tree and herb species of Kheyroud forest in northern Iran

We investigated the effects of grazing on natural regeneration, quantity, and diversity of woody species and dominant herb species in Kheyroud forest in northern Iran. We sampled vegetation in 5m2 plots in custom units, which are demarcated resource areas traditionally used by local livestock producers. The authors quantified number of species, height of seedlings, and diameter of seedlings. Height classes were 0-30 cm, 30-130 cm, and >130 cm, and diameter classes were 0-2.5 cm, 2.5-5 cm and 5-7.5 cm. The density of seedlings declined with distance from corral until reaching the custom unit boundary. Most seedlings had diameters of 0-2.5 cm and heights of 0-30 cm. Predominant species, Carpinus betulus and Acer capadocicum, were in plots near the centers of custom units, Fagus orientalis, Acer velutinum, Quercus castanifolia species were dominant in plots near the custom unit boundary. Plant species such as Oplismenus undulatifolius, Euphorbia amygdaloides, Rubus fruticos and Pteridium aquilinum were dominant in plots nearer to forest corral. Healthy seedlings were more numerous in plots nearest the corral, while defective and deformed seedlings were more abundant away from the corral. We conclude that grazing had negative effects on the quantity and quality of vegetative regeneration. Continuation of overgrazing will not only endanger the sustainability of forest ecosystems, but also will increase the challenge of sustainable forest management.     

Recovery of Baikiaea forest of southwestern Zambia from shifting cultivation and its implications for sustainable management

We studied the dominant species by age category of re-growth, and how subsistence forest use through shifting cultivation impacted on the floristic composition of Baikiaea forest. For re-growth stands, variable sampling method was adopted in data collection while in mature stands, a sample plot size of 50 m 9 50 m was used at each of three study sites. Distribution of species by age categories showed that shrub, herb, and grass species were abundant in young re-growth stands while woody vegetation became common with increasing age of the re-growth stand. Hierarchical clustering for common woody species showed several species associations with age categories and also with relatively undisturbed woodland. Common regeneration mechanisms of key woody species were mainly by seed(48%), coppicing(40%) and root suckers(12%). The young re-growth stands of 6–10 and 11–15 years were characterized by B. petersiana, B.massiensis, Combretum zeyheri, and Guibourtia coleosperma. Older stands(16–20 years after abandonment) were characterized by B. plurijuga, Pterocarpus antunesii, and Baphia massiensis, thus closely mimicking the relatively undisturbed forest whose dominant key woody species were B. plurijuga, P. antunesii, and G. coloesperma. There were many stems in younger stands(2–5 years) and fewer stems in older re-growth stands of 16–20 years after abandonment following shifting cultivation. Older regrowth stands(16–20 years) were similar to undisturbed stands(P \ 0.005). The similarity between re-growth stands of 16–20 years and control stands demonstrates the recovery of Baikiaea forest over time after cessation of shifting agriculture. Baikiaea forest requires some disturbance to perpetuate the dominant species and begins to show signs of recovery from shifting cultivation within16–20 years after abandonment. This is contrary to assertions that this ecosystem could take up to about 100 years for abandoned fields to begin showing signs of     

Vegetation structure,dominance patterns and height growth in an Afromontane forest,Southern Africa

Information on forest structure is fundamentally important to track successional vegetation dynamics for efficient forest management.This study reports on vegetation characteristics,dominance patterns and species height growth in a northern mistbelt forest type in South Africa.Common alpha-diversity indices(species richness and Shannon-Weiner diversity),structural vegetation parameters(tree density and basal area),and species importance value index were used.Size class distribution and height-diameter allometry were further examined for the overall stand and most important species.Stem densities(472.0±43.5 and 605.3±28.1 trees ha^-1 for C 5 cm to\10 cm and C 10 cm dbh(diameter at breast height)classes,respectively)and basal area values(1.99±0.19 and 48.07±3.46 m^2 ha^-1,respectively)are comparable to other Afromontane forests in East Africa.The overall stand showed an inverted-J shaped distribution pattern which is a typical feature of stand size class distribution in most natural forests.Most ecologically important species also exhibited an inverted-J shaped distribution pattern,suggesting good regeneration and recruitment potential.There were significant differences in species on height,reflecting species-specific height growth patterns,possibly a result of intrinsic growth potential and competitive interactions.The present study suggests that conservation and management policies,including protection of surrounding land uses against fire,contribute to maintaining a successful recovery of these forests.However,it should be noted that these forests may be experiencing relatively slow dynamic flux as a result of the overmature state of some trees with several years under relatively strict protection.     

Diversity and regeneration status of Sarkot Van Panchyat in Garhwal Himalaya, India

We investigated the floristic composition, phytosociological and regeneration status of Sarkot Van Panchyat (community forest) in Chamoli district of Garhwal Himalaya. A total of 52 plant species of 46 genera and 26 families were recorded, which included 12 trees, 18 shrubs and 22 herb species. Quercus leucotrichophora was dominant tree species in sapling and seedling layers, followed by Lyonia ovalifolia and Rhododendron arboreum.Out of 12 tree species, 7 species in seedling stage and 8 species in sapling stage were recorded in the study area. The 44.41% species in the study area showed good regeneration status, 16.66% species were fairly regenerating,and 8.33% species showed poor regeneration status, while 33% species were not regenerating. Number of individuals from lower girth classes (0 10 cmand 10 30 cm) showed decreasing trend with the increase in size of girth class. Shannon index (H) for trees, shrubs and herbs was recorded as 1.82,2.24 and 2.41 respectively. Simpsons index (CD) was recorded as 0.21, 0.12and 0.12 for trees, shrubs and herbs respectively. The forest should be divided into compartments for better management purpose and each compartment should be closed for five years to assist regeneration and enrichment planting may also be carried out for sustainable management.     

Study on Distribution Pattern of Plant Diversity of Forest Vegetation in Luofu Mountain,Guangdong

Through sample plot survey and statistic analysis, this paper adopts ecological method to study the characteristics of plant diversity of forest vegetation in Luofu Mountain, Guangdong. The results show that there is a great plant diversity of forest vegetation in Luofu Mountain owing to the ascendancy of aqueous and thermal condition in subtropical zone. The total number of species in 4 500 m^2 sample plot（s） are 170 with 3 870 individual plants in total; Dahl species richness index （D） is 44.932; Simpson diversity index （L,D） is 0.022, 0.022; Simpson （1982） diversity index （D） is 3.806; Pielou evenness index （E） is 0, 984 and Hulbert evenness index （E） is 0.815; Shannon-wiener diversity index （information index H′） is 4.188; Asymmetry index （r） is 0.185. These indexes show that a better habitat will bring about plant diversity of forest vegetation, and the diversity of zonal vegetation shows that the higher latitude is, the less species of vegetation can be found. Besides, vertical change of plant diversity of forest vegetation in Luofu Mountain is obvious. Its species richness index and plant diversity index show that monsoon evergreen broad-leaved forest is the tallest, mountain evergreen broad-leaved forest follows as the second and conifer-broad-leaved mixed forest is the shortest. The Wilson β-diversity index, which is obtained by comparison between forest vegetation below 300 m and forest vegetation between 600-900 m, is 0.621. Calculated from comparison between forest vegetation in 600-1 100 m and forest vegetation in 900-1 100 m, the Wilson β-diversity index is 0.727; by comparing forest vegetation below 300 m with forest vegetation in 900-1 100 m, the Wilson β-diversity index is 1.877. This shows that the plant diversity of forest vegetation is affected by the change in gradient of elevation.     

Coarse woody debris features of a warm temperate deciduous broad-leaved forest,northern China

Stocking and structural composition of a deciduous broad-leaved forest were determined to predict coarse woody debris quantity by quantifying the empirical relationships between these two attributes. The most ecologically significant families by stem density were Salicaceae, Betulaceae, Fagaceae, and Aceraceae. P opulus davidiana was the most dominant species followed by B etula dahurica, Quercus mongolica, and Acer mono. The four species accounted for 69.5% of total stems. Numerous small-diameter species characterized the coarse woody debris showing a reversed J-shaped distribution. The coarse debris of P. davidiana, B. dahurica, and Q. mongolica mainly comprised the 10–20 cm size class, whereas A. mono debris was mainly in the 5–10 cm size class. The spatial patterns of different size classes of coarse woody debris were analyzed using the g-function to determine the size of the tree at its death. The results indicate that the spatial patterns at the 0–50 m scale shifted gradually from an aggregated to a random pattern. For some species, the larger coarse debris might change from an aggregated to a random distribution more easily. Given the importance of coarse woody debris in forest ecosystems, its composition and patterns can improve understanding of community structure and dynamics. The aggregation pattern might be due to density dependence and self-thinning effects, as well as by succession and mortality. The four dominant species across the different size classes showed distinct aggregated distribution features at different spatial scales. This suggests a correlation between the dominant species population, size class, and aggregated distribution of coarse woody debris.