scholarly journals The Fate of a Tropical Rainforest in Nigeria: Abeku Sector of Omo Forest Reserve

2013 ◽  
Vol 6 (2) ◽  
pp. 116-130 ◽  
Keyword(s):  
Basal Area ◽  
Floristic Composition ◽  
Abundant Species ◽  
Diversity Indices ◽  
Forest Monitoring ◽  
Forest Reserve ◽  
Mean Values ◽  
Permanent Sample Plots ◽  
Large Trees ◽  
Number Of Stems

Sixteen permanent sample plots of one hectare each, established in 1985 at Abeku sector of Omo Forest Reserve, South west Nigeria by the European Economic Community/ Nigeria Federal Government (High Forest Monitoring Plots Project) (EEC/HFMPP) were used for this study. The plots were re-enumerated in 1987. Further assessment took place in 1997 and 2000 respectively for the purpose of assessing the floristic characteristics of the plots. The present study aims at assessing the floristic composition during the sampling years. Out of the original 16 plots only eleven and nine plots were available for assessment in 1997 and 2000 respectively. The remaining plots had been converted to plantations of arable and cash crops. The numbers of tree species encountered were 98, 109, 95 and 71 for 1985, 1987, 1997 and 2000 enumerations respectively. Also 28,31, 29 and 23 families were encountered in 1985, 1987, 1997 and 2000 respectively. In terms of density, basal area and spread, the ten most abundant species are Diospyros iturensis (Plant nomenclature follows Hutchinson and Dalziel (1954-72); Keay (1989) and Lowe and Soladoye (1990)), (DIAL),Tabernaemontana pachysiphon (TAPA), Octolobus angustatus (OLAN), Strombosia pustulata (SBPU), Diospyros dendo (DIDE), Diospyros suaveolens (DISU), Drypetes gossweileri (DRGO), Rothmania hispida (ROHI), Hunteria unbellata (HUUM) and Anthonotha aubryanum (ASAU) and the six most prominent families are Ebenaceae, Apocynaceae, Euphorbiaceae, Sterculiaceae, Olacaceae and Rubiaceae .Mean number of stems per hectare ranges from 400.44 to 1134.0 for the small trees (5-20cm dbh); 89.78 to 174.25 for the medium trees (20-40cm dbh) and 8.33 to 17.06 for the large trees (> 40cm dbh) Mean basal area per hectare ranges from 4.94m2 to 8.81m2 for the small trees, 5.4m2 to 9.63m2 for the medium trees and 4.64m2 to 9.04m2 for the large trees. Inverse of Simpson diversity indices range between 15.1 to 16.27 for the small tree, 13.43 to 16.37 for the medium trees and 23.44 to 26.34 for the large trees. The highest mean values per hectare of these parameters were found in 1987 enumeration, while the least values were found in the year 2000 enumeration. This variability may not be due only to the number of plots available for enumeration alone, but also as a result of poaching in the remaining plots before the 2000 enumeration. The study recommends that conscious efforts should be made to protect and maintained the permanent sample plots not only to reduce the possibility of encroachment but also to achieve the objective for which they were established which was to elucidate the dynamics and growth pattern of the natural rainforest. There is also a need for international assistance to achieve this.

Forest structure, floristic composition and soils of an Amazonian monodominant forest on maracá Island, Roraima, Brazil

1997 ◽  
Vol 54 (1) ◽  
pp. 1-38 ◽  
Author(s):  
M. T. Nascimento ◽  
J Proctor ◽  
D. M. Villela
Keyword(s):  
Forest Type ◽  
Basal Area ◽  
Floristic Composition ◽  
Abundant Species ◽  
Forest Types ◽  
Canopy Layer ◽  
Lowland Forest ◽  
Low Concentrations ◽  
Density Values ◽  
Set Up

Maracá is a riverine island located in the Rio Uraricoera in Roraima State (Brazil) and has an area of about 100,000ha. A forest type dominated by Peltogyne gracilipes Ducke (Caesalpiniaceae) occurs on Maracá Island on a range of soil types. This study compares the structure, floristic composition and soils of the Peltogyne forest with the most widespread lowland forest type on Maracá. Three 0.25ha plots were set up in each of three forest types: Peltogyne-rich forest (PRF), Peltogyne-pooi forest (PPF) and forest without Peltogyne (FWP). Within each plot all trees (≤ 10cm dbh) were recorded. Seedlings and saplings were sampled in subplots of 2m × 1m (seedlings) and 4m × 4m (saplings). In the PPF and FWP, Sapotaceae were the most important family with the highest relative dominance and relative density values. Caesalpiniaceae showed high values in the PRF and PPF. Licania kunthiana, Pradosia surinamensis and Simarouba amara occurred in the canopy layer in all the forest types. Peltogyne dominated the canopy in the PRF and comprised 20% of stems and 53% of the total basal area of all trees ≥ 10cm dbh, and 91% of the stems and 97% of the total basal area of individuals ≥ 50cm dbh. In PPF, Lecythis corrugata and Tetragastris panamensis were the most abundant species, followed by Peltogyne. In the FWP the most abundant trees (≥ 10cm dbh) were Licania kunthiana and Pradosia surinamensis. In all forest types, the soils were sandy and acid with low concentrations of extractable phosphorus and exchangeable cations, but the soils under PRF were notably richer in magnesium.

scholarly journals Modelling regeneration and recruitment in a tropical rain forest

1992 ◽  
Vol 22 (9) ◽  
pp. 1235-1248 ◽  
Author(s):  
Jerome K. Vanclay
Keyword(s):  
Rain Forest ◽  
Tropical Rain Forest ◽  
Growth Models ◽  
Basal Area ◽  
Relative Number ◽  
Site Quality ◽  
Permanent Sample Plots ◽  
Second Stage ◽  
Number Of Stems ◽  
Stand Basal Area

A two-stage model predicts the recruitment (i.e., the number of stems reaching or exceeding 10 cm DBH) of the 100 species that account for 97% of all the recruitment observed on 217 permanent sample plots in the tropical rain forest of north Queensland. The first stage predicts the probability of the occurrence of any recruitment from stand basal area and the presence of that species in the existing stand. These probabilities can be implemented stochastically, or deterministically by summing the probabilities and initiating recruitment on unity. The second stage indicates the expected amount of recruitment, given that it is known to occur, and employs stand basal area, the relative number of trees of that species in the stand, and site quality. This approach is easily implemented in growth models and planning systems.

scholarly journals Floristic Composition and Structure in Relation to Elevation in the Togo Plateau Forest Reserve in Ghana

2020 ◽  
Vol 1 (6) ◽  
Author(s):  
Gilchrist K. Faith Dogor ◽  
Emmanuel Acquah ◽  
Alexander K. Anning
Keyword(s):  
Elevation Gradient ◽  
Basal Area ◽  
Floristic Composition ◽  
Species Identity ◽  
R Software ◽  
Elevation Gradients ◽  
Forest Reserve ◽  
Composition And Structure ◽  
Special Scientific ◽  
Geographical Locations

Plateau ecosystems are of special scientific and conservation interests as they harbour rich plant diversity and exhibit considerable spatial variability along elevation gradients. In this study, variations in floristic composition and structure in relation to elevation were studied in six-fringed communities Hohoe (HH), Alavanyo (AL), Santrokofi (SA), Akpafu (AK), Bowuri (BO), and Nkonya (NK) of the Togo Plateau Forest Reserve in Ghana to better provide explicit and effective management of this ecological hotspot. A total of 180 plots (each measuring 25m × 25m) were demarcated across the six communities for sampling of trees (DBH measured at 1.3 m above ground ≥10 cm). Smaller nested plots, measuring 5m × 5m and 1m × 1m were used for sampling saplings (DBH < 10 cm, height > 1.5 m) and seedlings (DBH < 3 cm, height < 1.5 m), respectively. Species identity and abundance and elevation were recorded for each plot. Relationships of elevation gradients with vegetation attributes were analysed using simple linear regression and R software package. A total of 281 plant species (164 trees, 60 saplings and 57 seedlings) belonging to 66 families were recorded in the study. Leguminosae, Apocynaceae and Euphorbiaceae were the most dominant families across and along the elevation gradient. The average basal area of trees was calculated as 44.72 m2/ha and varied across the six communities (ranged from 57.10 m2/ha at BO to 33.10 m2/ha at AL) whereas the Shannon-Weiner Index (H’) averaged as 3.99 and varied across the six communities (ranged from4.14 m2/ha at BO to 3.89m2/ha at AL) and evenness index averaged as 0.96 (ranged from1.00at BO to 0.92 at AL). The saplings and seedlings also follow a similar pattern of composition and structure. The geographical locations of the study communities which somehow correspond with different elevations to the plateau (i.e., BO, NK occur in lower elevations, SA, AL in mid elevations and HH, AL in higher elevations) has been identified as the drivers of the composition and structure across the communities on the landscape. The most important trees listed in the study were C. pentandra, A. zygia, and T. superba. The saplings were A. camerunensis, M. puberula and C. ferruginea. The seedlings were C. odorata, P. hirsuta and C. affer. The most important tree species listed were distributed along a broad range of elevation. Results obtained revealed high biodiversity of the plateau. These findings may lead to a better understanding of the composition and structure of several plateau ecosystems found in Ghana and elsewhere.

scholarly journals Structure and composition of trees in Mount Tilu Nature Reserve, West Java, Indonesia

2020 ◽  
Vol 21 (6) ◽  
Author(s):  
Tri Cahyanto ◽  
Muhammad Efendi ◽  
DIAN MUHAMAD RAMDAN
Keyword(s):  
Tree Species ◽  
Nature Reserve ◽  
Basal Area ◽  
Principal Component ◽  
Floristic Composition ◽  
Diversity Indices ◽  
Species Structure ◽  
West Java ◽  
Conservation Area ◽  
Regeneration Status

Abstract. Cahyanto T, Efendi M, Ramdan DM. 2020. Structure and composition of trees in Mount Tilu Nature Reserve, West Java, Indonesia. Biodiversitas 21: 2674-2680. An understanding of the structure and composition of stands in a conservation area is needed to support sustainable management strategy. However, this information in the Mount Tilu Nature Reserve, Bandung District, West Java area is still lacking. This research was aimed to analyze the structure and composition of tree species in the block of Malagembol forest, Mt. Tilu NR. Data collection was carried out through vegetation analysis using sampling plot method with size of 10x100 m2 at three-level altitudes of 1530 m, 1745 m, and 1950 m asl. Observation parameters included species names, number of individuals, and diameter at breast height (dbh). Data were analyzed to determine the floristic composition, species structure based on their diameter class, relative basal area, diversity indices, and analysis of the importance of the main components of trees species through Principal Component Analysis (PCA). A total of 32 tree species from 23 families was found in the observation plots which was dominated by Fagaceae, Lauraceae, and Myrtaceae families. Some pioneer plants covered the gap in vegetation due to minor disturbance and residual damage in the past. Nonetheless, the dominance of stands with small diameters indicated good regeneration status following such disturbance. Based on these findings, we recommend protecting the vegetation in Mt. Tilu NR by limiting community activities that can disturb the forest.

Stand structure, thinning prescriptions, and density indexes in a Douglas-fir thinning study, Western Washington, U.S.A.

1983 ◽  
Vol 13 (1) ◽  
pp. 126-136 ◽  
Author(s):  
Chadwick Dearing Oliver ◽  
Marshall D. Murray
Keyword(s):  
Stand Structure ◽  
Volume Growth ◽  
Basal Area ◽  
Stand Density ◽  
Close Relation ◽  
Douglas Fir ◽  
Volume Number ◽  
Large Trees ◽  
Before And After ◽  
Number Of Stems

A Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) thinning study was established in 1959 in a stand begun after logging in 1930. Thinnings to set basal area densities were done in 1959, 1962, 1966, and 1970. On each plot both large and small trees were removed since average basal area per tree was kept constant before and after thinning. Volume growth varied greatly between plots of the same age, initial basal area, and site because of differences in stand structure. Large trees on a plot grew more per tree and per basal area than small trees. Stand basal area, stand volume, number of stems, or number of dominant and codominant trees were not closely related to volume growth per hectare, although density indexes giving weight to larger trees showed the closest relation. The lack of close relation between stand density indexes and growth found here and elsewhere probably means the indexes do not uniquely define stand structures; it does not necessarily mean that thinning will not increase volume growth per hectare. Volume growth per hectare after thinning to a given basal area density will be greater and probably more consistent if larger trees are left and enough time is allowed for the stand to recover following thinning.

Tree population changes in treated rain forest at Omo Forest Reserve, south-western Nigeria

1987 ◽  
Vol 3 (4) ◽  
pp. 291-313 ◽  
Author(s):  
D. U. U. Okali ◽  
B. A. Ola-Adams
Keyword(s):  
Rain Forest ◽  
Forest Biomass ◽  
Basal Area ◽  
Walsh System ◽  
Relative Distribution ◽  
Annual Increment ◽  
Forest Reserve ◽  
Number Of Species ◽  
Canopy Opening ◽  
Number Of Stems

ABSTRACTA review of previous evaluations of long-term changes in treated Nigerian rain forest is presented, to show that these studies have concentrated on economic species with little consideration of other species, or of forest biomass and structure.We examine regeneration and successional patterns in Omo Forest Reserve by comparing enumeration data taken before (1952) and after (1981) treatment of the forest by selective canopy opening and climber-cutting (Plot A), or clear-felling and burning (Walsh system) (Plot C).Before treatment, about 50 species in 25 families were found of stems ≥10 cm dbh, in 4.05 ha of the forest, the Euphorbiaceae contributing the greatest number of species while the medium-sized trees Diospyros alboflavescens (Ebenaceae) and Strombosia pustulata (Olacaceae) contributed more than 40% of the stems.Twenty-eight years after treatment (1981) the number of species and families remained similar to those in 1952, although smaller areas (0.75 ha) were enumerated; the treated plots were, however, dominated by early succession species such as Macaranga barteri, Musanga cecropioides, Cleistopholis patens, Funtumia elastica and Fagara macrophylla, and lacked an abundance of the ‘economic’ species that treatment had been expected to induce; the medium-sized trees that were dominant in 1952 were still abundant in Plot A but not in Plot C.For stems ≥ 30 cm dbh tree diversity (reciprocal of Simpson's index) was highest (15.7) in a 1952 plot and least (4.8) in the clear-felled plot enumerated in 1981; diversity of the 1952 plots, however, fell markedly to values lower than those for the 1981 plots when computation was based on all stems ≥10 cm dbh, presumably because of increase in abundance of small-stemmed species like Diospyros spp., Strombosia sp. and Rinorea sp., each represented by a large number of stems.Basal area was greatest (29.6 m2 ha−1) in the 1952 plots and least (12.7 m2 ha−1) in the clear-felled plots enumerated in 1981, but the relative distribution of basal area and number of stems in size-classes was similar in all the plots.Mean annual increment, computed by dividing the mean diameter (7.50 cm) of the stems in the clear-felled plots by the number of years (28) over which they had grown, was 0.27 cm.Nauclea diderrichii dominated the seedling regeneration from the first year after clear-felling and burning (1954) till the sixth year (1960), when seedlings of the Meliaceae entered the regeneration list and overall seedling density was 395 per hectare.Among the plots assessed in 1981, the standing crop was greatest in an untreated Control plot (229.6 t ha−1) followed by Plot A (159.7 t ha−1) and Plot C (91.1 t ha7−1), but the relative allocation of biomass to stem, branch, leaf, root and fruit fractions was comparable for all plots.The data are discussed in relation to other Nigerian forest studies and it is suggested that the main qualitative features of structural organization and the species composition of the top canopy synusia of mature secondary rain forest may be determined quite early in the development of the stand.

scholarly journals Current Status and Recent Stand Structure Dynamics in Mixed Silver Fir—European Beech Forests in Croatian Dinarides: Are There Differences between Managed and Unmanaged Forests?

2021 ◽  
Vol 13 (16) ◽  
pp. 9179
Author(s):  
Jura Čavlović ◽  
Marijana Andabaka ◽  
Mario Božić ◽  
Krunoslav Teslak ◽  
Karlo Beljan
Keyword(s):  
Basal Area ◽  
Forest Monitoring ◽  
Current Status ◽  
Stand Dynamics ◽  
Silver Fir ◽  
Recent Past ◽  
Beech Forests ◽  
Private Forests ◽  
Large Trees ◽  
Crown Defoliation

The environmental, social and economic potential of Dinaric uneven-aged forests along with the complex stand dynamics influenced by different long-term management approaches and environmental factors require comprehensive forest monitoring. This study aimed to explore differences in the current status and recent past dynamics of stand structures between unmanaged and managed mixed fir-beech forests in the Croatian part of the Dinaric Alps using large-scale data from an established monitoring system. From the 74 permanent sample plots distributed within the forest type measured in 2008 and re-measured in 2019, we stratified four strata (types of management regimes): (1) forests out of regular management and tree harvest for at least 30 years, (2) managed state forests on carbonate bedrock, (3) managed state forests on non-carbonate bedrock and (4) managed private forests. In each sample plot, 34 structural attributes were computed to assess indicators of their current status and recent past dynamics of stands in the studied forests. An increasing Q shape diameter distribution with a high number of large and very large trees characterize unmanaged forests and managed forests on non-carbonate bedrock. In managed state forests and private forests, variable (rotated sigmoid) and constant (negative exponential) results were obtained, respectively. Principal component analysis (PCA) distinguished managed and unmanaged forests with decreasing harvest volume and recruitment, increasing basal area, number of very large trees, average diameter at breast height (DBH), crown defoliation of firs and basal area of died beech trees. The current structure, recent and expected stand dynamics in the unmanaged forests (accumulation of standing volume, increase of large diameter trees and large snags, large share of beech, large mean DBH) can be recognized as old-growth attributes. The differences between the studied forest types, potential of both unmanaged and state managed fir-beech forests and approaches to sustain multifunctional forest management in the Dinaric region were discussed.

scholarly journals Species enumeration and diversity of fire experimental plot at Olokemeji Forest Reserve, Ogun State, Nigeria

Agro-Science ◽  
2021 ◽  
Vol 20 (2) ◽  
pp. 37-41
Author(s):  
A.J. Oloketuyi ◽  
O.D. Akinyemi ◽  
D.M. Taiwo ◽  
O.R. Jeminiwa ◽  
A.A. Ayodele
Keyword(s):  
Diversity Index ◽  
Abundant Species ◽  
Diversity Indices ◽  
Shannon Index ◽  
Experimental Plot ◽  
Gmelina Arborea ◽  
Forest Reserve ◽  
Ogun State ◽  
Evenness Index ◽  
High Dominance

The fire experimental plot of a total landed area of 0.174 ha was divided into three equal parts designated Plot A, Plot B and Plot C, corresponding to the early burnt, the late burnt and the control plot, respectively. Out of the 15 species of trees identified, six species belong to Fabaceae- Mimosoideae family and other families represented are Combretaceae, Meliaceae, Lamiaceae, Rubiaceae, Anacardiaceae, Urtiaceae and Sapotaceae. Gmelina arborea was the most abundant species and it was found in plot A, B and C. The diversity indices enumerated were Dominance index, Simpson index, Shannon index or diversity index and evenness index. Plot C had the highest abundance (species count), followed by Plot A and Plot B. While Plot B depicted a high dominance, dominance was low in Plot A and lowest in Plot C. This means that a particular species was dominating Plot B, which was Gmelina arborea. This Gmelina arborea also dominated Plot A but to a lesser extent compared to Plot B. Plot C was richer in species than Plot A and Plot B. The Shannon index was low across the three plots, but considerably highest in Plot C. Evenness index was moderate at Plot C, implying that there was an even distribution of tree species in Plot C, while evenness was low at Plot A and Plot B. Comparing the present data with the older data, it is clear that the fire experimental plot has undergone deforestation over the years, which requires urgent attention and reforestation. Key words: cluster, dendogram, deforestation, burning, richness

Structural characteristics and floristic composition of a Neotropical cloud forest, Monteverde, Costa Rica

1995 ◽  
Vol 11 (4) ◽  
pp. 481-495 ◽  
Author(s):  
Nalini M. Nadkarni ◽  
Teri J. Matelson ◽  
William A. Haber
Keyword(s):  
Structural Characteristics ◽  
Cloud Forest ◽  
Basal Area ◽  
Floristic Composition ◽  
Background Information ◽  
Montane Forests ◽  
Forest Reserve ◽  
Forest Density ◽  
Tropical Montane Forests ◽  
Floristic Characteristics

ABSTRACTThe Monteverde Cloud Forest Reserve protects a variety of primary montane forest communities on volcanic parent materials. We describe the structure and composition of the forest to provide background information for epiphyte and nutrient cycling studies and for comparison with other tropical montane forests. In a 4-ha study plot in leeward cloud forest, density of stems (2062 individuals ha−1 for stems >2 cm dbh, 555 individuals ha−1 for stems > 10cm dbh) and stem basal area (73.8 m2 ha−1 for stems >2 cm, 62.0 m2 ha−1 for stems >10 cm dbh) were high relative to other montane forests. Stems in a subset of the plot (c. 1/3 of the area) were identified and assigned to 47 families, 83 genera and 114 species, which is rich compared with other montane forests. Large stems had a higher spatial variability of structural and floristic characteristics than small stems.

scholarly journals Estructura, composición y diversidad de la selva baja caducifolia del Cerro Verde, Nizanda (Oaxaca), México

2017 ◽  
pp. 19 ◽  
Author(s):  
José A. Gallardo-Cruz ◽  
Jorge A. Meave ◽  
Eduardo A. Pérez-García
Keyword(s):  
Species Richness ◽  
Forest Cover ◽  
Conservation Status ◽  
Tropical Dry Forest ◽  
Basal Area ◽  
Floristic Composition ◽  
Dry Forest ◽  
Tropical Region ◽  
Mean Values ◽  
Seasonally Dry

In this study we describe the structure, floristic composition, and diversity of the tropical dry forest established on the Cerro Verde (Verde Hill), located at Nizanda (Isthmus of Tehuantepec, Oaxaca, Mexico). We censused woody plants with DBH Ɛ 1 cm (upper stratum) present in 30 100-m2 plots, and in five 4-m2 subplots within each of them, those plants with height &gt; 30 cm but &lt; 1 cm DBH (lower stratum). A total of 194 species belonging to 52 families were recorded. Species richness was identical in both strata (145 species), each contributing exclusively with ca. 25% of total recorded richness. Leguminosae was the most speciose family (27), followed by Asteraceae (20) and Euphorbiaceae (18). The most frequent species were Bursera simaruba + B. aff. cinerea (not distinguished in the field), Euphorbia schlechtendalii, Pilosocereus collinsii and Capparis verrucosa. Average richness by plot was 30 species. Mean values of indices based on species richness and abundances (Berger-Parker = 0.20;  Simpson = 0.09; Fisher’s[= 9.47; Shannon = 2.78; eveness = 0.82) indicated a high diversity and consequently a low dominance in this forest. Extrapolated values showed a total (upper + lower strata) density of 23,950 ind. ha-1 (830 ind. ha-1 with DBH Ɛ 10 cm), a forest cover of 446.7%, and a basal area of 53 m2 ha-1. Mean height of those individuals accounting for 10% of the highest trees by plot was 9.1 m. Tropical dry forest structure at Cerro Verde is comparable to other Mexican communities within the seasonally dry tropical region and indicates a good conservation status. This feature, together with its particular floristic composition, makes of this area a high priority site which requires inclusion in a formal conservation scheme.

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