Density Of Tree Species Research Articles

Factors affecting early red oak (Quercus rubra L.) regeneration near its northern distribution limit in Quebec

Red oak is an important species within the North American landscape, with climate change projections indicating a potential northward shift in its distribution. However, understanding the factors influencing its regeneration success at the northern limit remains limited. Site conditions and seed provenance adaptability may play critical roles. To bridge this knowledge gap, we conducted a seed transfer study in two northern red oak stands in Quebec. We firstly investigated stand regeneration history through dendrochronological characterization. Then, we monitored the survival and growth of saplings for four red oak provenances across a south-to-north gradient in field and greenhouse settings, with varying soil nutrient levels due to fertilization, and with or without protection from large herbivores. Results indicated that stands have similar age structures with red oak establishment coinciding with the last major fire disturbance in the early 1920s. However, tree species composition and density differed, suggesting differences in fire disturbance regime or ecological succession status prior to fire. Site had the largest influence on red oak regeneration, with the highest tree density and soil water availability site exhibiting a 29% higher survival rate. Protection against large herbivores also significantly impacted red oak seedling performance, leading to a 16% higher survival rate. Germination, survival and growth also significantly differed between provenances. The local (northernmost) provenance exhibited the poorest overall performance with 28 to 42% lower germination, survival and growth rates, while the two southernmost provenances exhibited superior germination and sprout survival. An increase in soil nutrient availability was beneficial to red oak in the greenhouse, but only marginally benefited survival and growth in the field, suggesting that this factor is of less importance than other factors (e.g., water and light availability) for red oak early regeneration. The findings of this study suggest that silvicultural efforts to favor red oak should focus on site and provenance selection, and that water availability is currently limiting red oak regeneration success at acorn and early seedling life stages (i.e., 1 year old seedlings) near its northern distribution limit.

Diverging Elevational Patterns of Tree vs. Epiphyte Species Density, Beta Diversity, and Biomass in a Tropical Dry Forest.

There is evidence to suggest that vascular epiphytes experience low competition for resources (light, water, and nutrients) compared to terrestrial plants. We tested the hypothesis that low resource competition may lead to higher nestedness among vascular epiphyte assemblages compared to trees. We studied the species composition and biomass of epiphytes and trees along an elevation gradient in a tropical dry forest in SW Ecuador. Both life-forms were inventoried on 25 plots of 400 m2 across five elevation levels (550-1250 m). Tree species density and total species richness increased with elevation, whereas basal area and biomass did not show significant trends. Epiphyte species density and richness both increased strongly with elevation, in parallel to biomass. Plot-level compositional changes were similarly strong for both life-forms. We attribute elevational increases in the species richness of trees and epiphytes to increasing humidity, i.e., more mesic growth conditions. We attribute the more pronounced elevational increase in epiphyte biomass, species density, and richness-the latter coupled with a higher degree of nestedness-to the greater moisture dependency of epiphytes and relatively low direct competition for resources. Our study provides a first comparison of elevational trends in epiphyte and tree diversity and biomass for a tropical dry forest.

Community Structures of On-Farm Tree Species in Budaka Sub-County, Budaka District, Eastern Uganda

Tree species population composition and diversity refers to the variety of tree species and their relative abundance in an ecosystem. In most tropical agro-ecosystems where land cover changes are faster than natural restoration, tree species composition, distribution, richness and diversity and the services provided by them are particularly susceptible to change globally from continuous stress factors such as bushfires, logging and cultivation. Data for the study was obtained from trees inventory using a systematic random sampling technique. A quadrant measuring 25m x 25m was laid. A total of sixty quadrants were used in the study. Each quadrant was demarcated using a measuring tape and its boundaries marked using pegs. All tree species encountered in each quadrant were identified and recorded. The unidentified specimens were collected, pressed and taken to Makerere University herbarium for proper identification. The results from the study revealed a total of 28 tree species belonging to 16 families were documented as being used by people in the four surveyed villages of Budaka Sub County, where Family Moraceae had the highest number of tree species with no significance difference in the density, diversity, richness, evenness, poles, saplings and seedlings of tree species across the four villages (Kruskal-Wallis P< 0.05). This indicates that these trees are under threat in the study area. This situation is quite alarming and calls for more resourceful and sustainable management and conservation techniques. Among others, it is suggested that laws should be enacted to protect the resource from further timber and fuel wood exploitation in the area in order to allow it to regenerate fully.

Relative decline in density of Northern Hemisphere tree species in warm and arid regions of their climate niches

Although climate change is expected to drive tree species toward colder and wetter regions of their distribution, broadscale empirical evidence is lacking. One possibility is that past and present human activities in forests obscure or alter the effects of climate. Here, using data from more than two million monitored trees from 73 widely distributed species, we quantify changes in tree species density within their climatic niches across Northern Hemisphere forests. We observe a reduction in mean density across species, coupled with a tendency toward increasing tree size. However, the direction and magnitude of changes in density exhibit considerable variability between species, influenced by stand development that results from previous stand-level disturbances. Remarkably, when accounting for stand development, our findings show a significant change in density toward cold and wet climatic conditions for 43% of the species, compared to only 14% of species significantly changing their density toward warm and arid conditions in both early- and late-development stands. The observed changes in climate-driven density showed no clear association with species traits related to drought tolerance, recruitment and dispersal capacity, or resource use, nor with the temperature or aridity affiliation of the species, leaving the underlying mechanism uncertain. Forest conservation policies and associated management strategies might want to consider anticipated long-term species range shifts alongside the integration of contemporary within-distribution density changes.

The pivotal role of water potential in phenology and seed germination of Abies spectabilis in the western Himalayan treeline region

Abies spectabilis (East Himalayan Fir), a dominant timber-producing species in the Himalayas, plays a dynamic role in ecological balance and sustains various habitats across temperate to subalpine altitudes. Himalayan montane forests express signs of changes in the growth, regeneration, and population density of forest tree species due to ongoing climate change, including its upper distribution limit. The research was conducted at 30°11´02˝N and 79°39′36˝E, ranging from 3,100 to 3,500 m asl elevation in the treeline ecotone of western Himalaya. The study presents a comprehensive perspective on how water availability and its intricate interactions with climatic and ecological variables shape the dynamics of treeline ecosystems. The study’s phytosociological analysis of treeline sites revealed the complex interplay between species composition, adaptability, and regeneration potential. The eco-physiological aspects of water balance were thoroughly explored, underscoring how plants employ various strategies to cope with changing water availability. The soil moisture content ranged from 32.17 to 73.50%. The dynamic nature of water potential (pre-dawn (ΨPD) and mid-day (ΨMD)) across seasons and years reflects and varies between −0.13 and − 1.25 MPa, the species’ ability to adjust and manage water balance according to environmental shifts. Osmotic potential at full turgor varied from −0.72 to −1.77 MPa, these adjustments are crucial for key life cycle events of vegetative and reproductive phases of species. The strong correlation of water potential (Ψ) and phenophases emphasizes the importance of water status in regulating these vital processes. Furthermore, the study delved into the maturation and germination processes, highlighting the significance of Ψ and moisture content in seed development and germination success. The maximum germination of 46.33% was observed when the seed moisture content was 30.90 ± 3.11%. The observed correlations between cone characteristics and seed parameters indicate the existence of trade-offs that impact seed size, weight, and germination capacity, contributing to the overall fitness of the species.

Determinants of spatial distribution of trees outside forests along urban-rural gradients: A review

Urbanization can create uncertainty for biodiversity. Understanding the spatial distribution of trees along urban-rural gradients is crucial for sustainable land management and the conservation of biological diversity. However, limited information is available on the factors influencing the distribution of trees outside forests along urban-rural transition gradients. This paper uses the Preferred Reporting items for Systematic Reviews and Meta-Analyses (PRISMA) to review how distance from urban centers, land use types, socio-economic disparities, and community attitudes and perceptions impact the spatial distribution of trees outside forests along urban-rural gradients. The review indicates that the species composition, diversity, density, and spatial arrangement of trees outside forests vary along the urban-rural gradient. The most commonly cited factors influencing this distribution are respondents' attitudes and perceptions of trees, socio-economic factors, and land use variations. Distance from the urban center was the least cited factor. However, there is significant variation in how different factors impact this distribution from study to study. Therefore, further research is needed to better understand the factors driving changes in the diversity of trees outside forests in various urban-rural contexts and to determine whether variations exist across different settings.

Changes in floristic and vegetation structure in a chronosequence of abandoned gold-mining lands in a tropical Amazon forest

This study analyzes floristic and vegetation structure changes during forest succession after disturbances caused by small-scale gold mining in Madre de Dios (Peru). We compared the floristic and vegetation structure of a reference forest against three sites with different periods of abandonment after mining (5, 11 and 23-years). Three 20 × 60 m plots were defined on each site, and all tree species with a DBH >1 cm within the plots were inventoried. To evaluate species diversity and similarity, the Importance Value, effective numbers of species (0D, 1D, and 2D), and Chao-Jaccard similarity index were calculated. We used the Nonmetric multidimensional scaling for similarity ordination and the PERMANOVA test to evaluate differences in floristic composition. We recorded 129 tree species in the study areas and statistically significant differences between initial and intermediate stages were observed regarding floristic composition, basal area, height, and DBH. The transition from the initial successional stage to the reference forest produces an increase in basal area, species diversity, and floristic similarity. The 23-year-old stand had more species in common with the 11-year-old stand than the reference forest. Our results showed a high proportion of pioneer species and anemochory dispersal syndrome in the initial successional stages, but they decreased in later stages of the chronosequence. The floristic and structural attributes of forests throughout the chronosequence showed a fast recovery during secondary succession. After 23 years, the recovery of tree species density was 77 % of reference forest, while the relative recovery of species composition was much slower, on average 23 %. These results provide essential information to guide the selection of suitable species in ecological restoration projects after abandonment. Implementing forest restoration strategies based on reliable information to accelerate the process of vegetation succession is critical for recuperating areas degraded by gold mining at the Peruvian Amazon.

Evolutionary history shapes variation of wood density of tree species across the world

The effect of evolutionary history on wood density variation may play an important role in shaping variation in wood density, but this has largely not been tested. Using a comprehensive global dataset including 27,297 measurements of wood density from 2621 tree species worldwide, we test the hypothesis that the legacy of evolutionary history plays an important role in driving the variation of wood density among tree species. We assessed phylogenetic signal in different taxonomic (e.g., angiosperms and gymnosperms) and ecological (e.g., tropical, temperate, and boreal) groups of tree species, explored the biogeographical and phylogenetic patterns of wood density, and quantified the relative importance of current environmental factors (e.g., climatic and soil variables) and evolutionary history (i.e., phylogenetic relatedness among species and lineages) in driving global wood density variation. We found that wood density displayed a significant phylogenetic signal. Wood density differed among different biomes and climatic zones, with higher mean values of wood density in relatively drier regions (highest in subtropical desert). Our study revealed that at a global scale, for angiosperms and gymnosperms combined, phylogeny and species (representing the variance explained by taxonomy and not direct explained by long-term evolution process) explained 84.3% and 7.7% of total wood density variation, respectively, whereas current environment explained 2.7% of total wood density variation when phylogeny and species were taken into account. When angiosperms and gymnosperms were considered separately, the three proportions of explained variation are, respectively, 84.2%, 7.5% and 6.7% for angiosperms, and 45.7%, 21.3% and 18.6% for gymnosperms. Our study shows that evolutionary history outpaced current environmental factors in shaping global variation in wood density.

Biomass and Carbon Stock of Trees in a Tropical Moist Deciduous Forest of Kamrup Metropolitan District, Assam, India

The present investigation deals with the estimation of biomass and Carbon stock potential of tree species in a tropical moist deciduous forest of Kamrup Metropolitan district of Assam, India. For vegetation sampling of trees, the stratified random method was employed and biomass and Carbon stock of trees were estimated by using an allometric equation. Altogether 39 tree species representing 34 genera and 20 families were reported. A high total density and total basal cover (TBC) were reported during the investigation (1008 stem ha⁻¹ and 71.74 m² ha⁻¹ respectively). Total biomass (TB), total Carbon stock (TCS), and CO₂ equivalent were estimated to be 985.56 Mg ha⁻¹, 492.78 Mg C ha⁻¹, and 1808.50 Mg C ha⁻¹ respectively. Among the trees, Cassia fistula exhibited the highest amount of TB, TCS, and CO₂ equivalent (131.33 Mg ha⁻¹, 65.66 Mg C ha⁻¹, and 240.99 Mg C ha⁻¹ respectively). TCS displayed a positive correlation with density, TBC, and diameter of tree species. The study provides valuable information on biomass and Carbon sequestration potential of trees in the tropical moist deciduous forest, which could be of help to forest policymakers to ensure sustainable management of Carbon stock and hence promotes mitigation of global climate change.

Estrutura populacional e distribuição espacial de Guadua weberbaueri Pilg. em florestas nativas e antropizadas da Amazônia Ocidental brasileira

ABSTRACT Brazilian forestry laws do not provide specifications for the management of bamboo-dominated forests. This study aimed to characterize the bamboo population structure, its spatial distribution and the effects of shoot density on the diversity and density of dominant tree species in the southwest of the Amazon Rainforest. An inventory was carried out in forest with and without anthropogenic interference, and the height and diameter at breast height of the trees were measured, as well as the diametrical, vertical and spatial distribution of the shoots. The bamboo diametrical distribution presented an irregular behavior in the two areas under study and the vertical distribution behaved irregularly in the forest without anthropization, in an asymmetric negative way when compared to the forest that suffered anthropogenic disturbance. The bamboo spatial distribution did not show changes in its aggregate pattern between the studied environments, and its density did not present a significant correlation with the density and diversity of tree species.

Impact of community-based forest restoration on stand structural attributes, aboveground biomass and carbon stock compared to state-managed forests in tropical ecosystems of Sri Lanka.

Estimation of plant community composition, aboveground biomass and carbon stock is crucial for understanding forest ecology, strengthening environmental management, and developing effective tools and policies for forest restoration. This study was conducted in nine different forest reserves in Sri Lanka from 2012 to 2018 to examine the impact of community-based forest restoration (CBFR) on stand structural attributes, aboveground biomass, and carbon stock compared to state-managed forests. In total, 180 plots (90 plots in community-managed restoration blocks (CMRBs) and 90 plots assigned to state-managed restoration blocks (SMRBs)) were sampled at the study site. To conduct an inventory of standing trees, circular plots with a radius of 12.6 m (equivalent to an area of 500 square meters) were established. The Shannon diversity index, Allometric equations and Difference in Differences (DID) estimation were used to assess the data. Our study provides evidence of the positive impact of the CBFR program on enriching trees diversity. Considering stand structural attributes of both blocks showed higher trees density in the smaller diameter at breast height (DBH) category, indicating growth in both CMRBs and SMRBs. The results showed that tree biomass and carbon density were disproportionally distributed across the nine different forest reserves. On average, tree biomass and carbon density were higher in SMRBs (79.97 Mg ha-1, 37.58 Mg C ha-1) compared to CMRBs (33.51 Mg ha-1, 15.74 Mg C ha-1). However, CMRBs in Madigala reserve represent the highest biomass (56.53 and 59.92 Mg ha-1) and carbon density (26.57 and 28.16 Mg C ha-1). The results of biomass and carbon estimates were higher in all SMRBs in the nine different forest reserves compared to CMRBs. The findings suggest that future forest restoration programs in Sri Lanka should enhance participatory approaches to optimize tree species diversity, density and carbon storage, particularly in community-controlled forests. Our findings could assist developing tropical nations in understanding how CBFR impacts forest restoration objectives and improves the provision of ecological services within forests.

Successful forest restoration using plantation at high deer density: How neighboring vegetation drives browsing pressure and tree growth

Browsing can be an environmental stress to forest ecosystems, where the composition and structure of plant communities depend on the balance between ungulate browsing and the ability of plants to tolerate and acclimate to this stressor. Tree planting is a management tool for restoring forest whose integrity has been compromised by the intensity and repetition of browsing. This tool may be insufficient when the stress leading to forest degradation is ongoing. Balsam fir (Abies balsamea (L.) Mill.) plantations are used on Anticosti Island (Quebec, Canada) to restore winter habitat for white-tailed deer (Odocoileus virginianus Zimmermann, 1780). To promote natural regeneration and growth of planted firs that are the staple winter forage of deer, enclosures were temporarily erected and deer densities reduced to decrease browsing pressure. The stress induced by heavy browsing at the time of fence removal and the density of competitors in regenerating cutblocks, however, could compromise fir growth and forest recruitment. Our objective was to identify factors influencing browsing intensity and balsam fir’s growth following fence removal. We aimed to identify factors influencing lateral browsing intensity and number of trunk reiterations on fir at the landscape scale, including distance and size of the surrounding forests, and at the local scale through intraspecific density-dependence and interspecific associative effects. We then sought to identify the stressors most influencing balsam fir growth among browsing variables and a neighborhood crowding index (NCI). We measured browsing intensity and growth of 114 balsam firs 8 years following planting and again 2 and 4 years after dismantling two management enclosures. At the landscape scale, our results showed that when balsam fir was more than 150 m from a forest edge, the probability of browsing was close to zero and consistently a low percentage of shelter area surrounding a focal fir led to a decrease in browsing pressure. At the local scale, intensity of lateral browsing increased with the NCI of white spruce (Picea glauca (Moench) Voss). Fir growth was negatively influenced by the additive effects of browsing and NCI. Finally, our results showed that 19.7% (95 %CI: 4.5%, 42.6%) of the effect of the surrounding vegetation on growth was mediated by browsing. The success of forest ecosystem restoration through planting depends on density of neighboring tree species that can generate environmental stress by influencing growth indirectly through browsing as well as directly through competition for resources.

Species-Specific Allometric Equations, Biomass Expansion Factor, and Wood Density of Native Tree Species in the Dry Afromontane Forest of Ethiopia

A forest is a storehouse of carbon released from different sources when the activities of sustainable forest management, planting, and rehabilitation exist. However, few allometric equations are present to determine its contribution to carbon reduction. The target of the study was to develop species-specific allometric equations and establish a database for biomass expansion factor and wood density for five tree species grown in the dry Afromontane forest of Ethiopia. A direct or destructive sampling method was used on 62 trees from different diameter classes. The diameter at breast height and the total height of selected trees ranged from 7 to 48 cm and 6.7 to 23.4 m, respectively. Trees were felled and divided into various biomass sections. Stem and big branch discs were sampled to determine the wood density and volume of the trees. Sample wood and foliage were oven-dried for three days and two days at 105°C and 70°C, respectively, to get their dry weight. Total above-ground biomass was regressed using diameter at breast height, total height, wood density, and average crown diameter as independent variables. R software version 4.0.1 was used to fit the biomass equations. The best biomass models were determined to have lower AIC and RSE and highest adj. R2. The biomass expansion factor and wood density of five tree species ranged from 1.19 to 1.40 and 0.53 to 0.74 g/cm−3, respectively. Species-specific allometric equations were better than both mixed species and pan tropical models for the assessment of above-ground biomass in the Chilimo dry Afromontane forest of Ethiopia.

Species Composition and Diversity of Plants along Human-Induced Disturbances in Tropical Moist Sal Forests of Eastern Ghats, India

Plant biodiversity data are prerequisites for the sustainable management of a forest. We used quantitative ecological tools to determine the species composition, diversity (richness and evenness), population structure, distribution patterns, and regeneration status of trees in a Tropical Moist Sal Forest of Eastern Ghats, India. For this purpose, a field inventory was conducted during 2020–2022 in sixteen 1.0 ha forest stands along a human-induced disturbance gradient. A total of 161 species (61 trees, 40 shrubs, 60 herbs) belonging to 77 families and 143 genera were recorded in the 16.0 ha of forest area. The results revealed a significant (p < 0.01) decrease in the tree and shrub species density, basal area, species richness, and diversity along the gradient of disturbance. However, in the case of herbs, the Shannon–Weiner diversity index increased significantly (p < 0.01) with increasing disturbance levels. Irrespective of forest types and disturbance levels, the tree diameter class (10–30 cm) accounted for the highest stem density in the forest. A mixed trend was found in the case of the basal area; the >41 cm diameter class constituted the highest basal area in the Pure Sal Forest while the 10–30 cm class was in the Moist Deciduous Forest without Sal. Tree species richness was found higher in lower diameter classes. Disturbances impacted the distribution pattern of trees; in the Pure Sal Forest, the contagious distribution of trees were 61.54%, 40%, and 12.5% in undisturbed, low-disturbed, and moderately disturbed sites, respectively. The percent of trees showing random and regular distribution increased with the increased level of disturbance in all forest types. The number of tree species having good regeneration decreased with the increased disturbance intensity in all forest types. Frequent grazing, repeated forest fires, and poor soil seed banks at the Moderately Disturbed site were the main reasons for the poor/no regeneration of Pterocarpus marsupium, Adina cordifolia, Terminalia bellerica, and some other economical species. Significant changes in structural attributes of the tree community revealed the impact of human-induced disturbances in the Moist Sal Forests of Eastern Ghats. The disturbance mosaics promoted the growth of many invasive weed species and lianas, depleting the number of valuable species in the forest. This study suggests the adaption of sustainable biodiversity conservation approaches through the active participation of the tribal so that the remnants the Moist Sal Forests of Eastern Ghats can be controlled to prevent further degradation.

Allometric relationships between stem diameter, height and crown area of associated trees of cocoa agroforests of Ghana

Allometric models which are used to describe the structure of trees in agroforestry systems are usually extrapolated from models developed for trees in forest ecosystems. This makes quantitative assessment of the functions of shade trees in agroforestry systems challenging since increased availability of light and space in these systems may induce structural differences from those growing under forest conditions. We addressed this issue by providing species-specific allometric information on the structural characteristics of associated shade trees on cocoa agroforestry systems and assessed if allometries conformed to theoretical predictions. At the plot level, stand and soil characteristics affecting tree structural characteristics were assessed. The study was conducted in cocoa agroforestry systems at Suhum, Ghana. The height-diameter at breast height (H-DBH) allometry had the best fits (R2 = 53–89%), followed by the crown area (CA)-DBH allometry (R2 = 27–87%) and then the CA-H allometry (R2 = 22–73%). In general, the scaling exponents of the CA-DBH, H-CA and H-DBH allometries conformed to the metabolic scaling theory (MST). However, both the CA-DBH and H-DBH allometries diverged from the geometric similarity model. Though forest tree species had similar crown areas as fruit trees, they were slenderer than fruit trees. Tree slenderness coefficients were positively correlated with soil P, Ca, Cu and the ratios (Ca + Mg):K, (Ca + Mg):(K + Na) and Ca:Mg, but not C:N while DBH and H were correlated with soil P and C:N ratio. Our results show that critical soil nutrients and their ratios affects shade tree structural attributes (e.g. slenderness and CA), which possibly restrict variations in species-specific allometries to a narrow range on cocoa systems. Furthermore, shade tree species richness and density are better predictors of relative canopy projection area (a proxy for shade intensity) than tree species diversity. In conclusion, the results have implications for shade tree species selection, monitoring of woody biomass and maintenance of biodiversity.

Satellite-based assessment of water use and leaf area efficiencies of dryland conifer forests along an aridity gradient

Dryland forests worldwide are increasingly threatened by drought stress due to climate change. Understanding the relationships between forest structure and function is essential for managing dryland forests to adapt to these changes. We investigated the structure-function relationships in four dryland conifer forests distributed along a semiarid to subhumid climatic aridity gradient. Forest structure was represented by leaf area index (LAI) and function by gross primary productivity (GPP), evapotranspiration (ET), and the derived efficiencies of water use (WUE = GPP/ET) and leaf area (LAE = GPP/LAI). Estimates of GPP and ET were based on the observed relationships between high-resolution vegetation indices from VENμS and Sentinel-2A satellites and flux data from three eddy covariance towers in the study regions between November 2015 to October 2018. The red-edge-based MERIS Terrestrial Chlorophyll Index (MTCI) from VENμS and Sentinel-2A showed strong correlations to flux tower GPP and ET measurements for the three sites (R2cal > 0.91, R2val > 0.84). Using our approach, we showed that as LAI decreased with decreasing aridity index (AI) (i.e., dryer conditions), estimated GPP and ET decreased (R2 > 0.8 to LAI), while WUE (R2 = 0.68 to LAI) and LAE increased. The observed global-scale patterns are associated with a variety of forest vegetation characteristics, at the local scale, such as tree species composition and density. However, our results point towards a canopy-level mechanism, where the ecosystem-LAI and resultant proportion of sun-exposed vs. shaded leaves are primary determinants of WUE and LAE along the studied climatic aridity gradient. This work demonstrates the importance of high-resolution (spatially and spectrally) remote sensing data conjugated with flux tower data for monitoring dryland forests and understanding the intricate structure-function interactions in their response to drying conditions.

Impacts of Earthquake and Earthquake-induced Disasters on Community Forests in Nepal

Managing the commons is a challenging issue during crisis such as earthquakes. We considered four community forests, two from Gorkha and one from each of Dolakha and Sindupalchowk districts that were major earthquake affected areas. The study made use of ecological and socioeconomic survey techniques to assess the impacts of earthquake on community forests and management status of those forests. We calculated density of seedling, sapling and tree species and diameter size distribution of trees. We also analysed the forest status changes before and after the earthquake events and distribution of timber and fire wood in the community forest user groups. Seedling, sapling and adult trees number wise regeneration status of trees was good in all the studied forest whereas DBH size class diagram were bell shaped indicating unsustainable regeneration. Most of the respondents reported poor forest management after the earthquake and wood distribution has drastically increased after the earthquake 2015. From this study it is recommended that community forest management practices should be resilient to disasters and prepare alternative solutions to lower the pressure on forest products so as to maintain sustainable regeneration of forest trees and regular supplies of resources in future.

Economic Prospects of some Ecosystem Services Accessed by Communities around Girei Forest Reserve of Adamawa State

The economic prospects of ecosystem services accessed by communities around Girei forest reserve were investigated. This was as a result of over dependence on the forest reserve as a source of livelihood. A stratified random sampling was used to interview 180 household heads on their socio-economic characteristics and the benefits they derived from the forest reserve. Relevant descriptive statistical tools were used to analyze the data. The results showed that most households were headed by males 91.3% while 8.7% of the households were headed by females. The mean annual income of the respondents was ₦267,401. A lot of benefits were obtained from the forest reserve such as honey, firewood, poles, medicines, grass etc. The estimated annual monetary value of ecosystem provisioning services obtained from the forest reserve is ₦25,907,400 per annum. However, due to the enormous benefits derived from the forest reserve and the unsustainable harvest of the forest resources as a source of livelihood, quantitative assessment of the indigenous tree species in Girei forest reserve was also carried out. To achieve these;;the relative frequency, density, relative dominance, and importance value index of tree species in the forest reserve were determined. The tree with the highest dominance Tamarindus indica (39.1) while the least is Prosopis africana (0.54). The importance value index shows that Tamarindus indica (28.67) has the highest value index while the least is Parkia biglobosa (1.90). The result of diversity of the tree species was 1.941 using Shanno’s diversity index which indicates uncertainty of the species in the study area. Therefore, there is need for urgent concerted management and policy actions which are geared towards monitoring the health and integrity of Girei forest reserve such it can continue to generate ecosystem services which are beneficial to the present and future generations.

Economic Prospects of some Ecosystem Services Accessed by Communities around Girei Forest Reserve of Adamawa State

The economic prospects of ecosystem services accessed by communities around Girei forest reserve were investigated. This was as a result of over dependence on the forest reserve as a source of livelihood. A stratified random sampling was used to interview 180 household heads on their socio-economic characteristics and the benefits they derived from the forest reserve. Relevant descriptive statistical tools were used to analyze the data. The results showed that most households were headed by males 91.3% while 8.7% of the households were headed by females. The mean annual income of the respondents was ₦267,401. A lot of benefits were obtained from the forest reserve such as honey, firewood, poles, medicines, grass etc. The estimated annual monetary value of ecosystem provisioning services obtained from the forest reserve is ₦25,907,400 per annum. However, due to the enormous benefits derived from the forest reserve and the unsustainable harvest of the forest resources as a source of livelihood, quantitative assessment of the indigenous tree species in Girei forest reserve was also carried out. To achieve these;;the relative frequency, density, relative dominance, and importance value index of tree species in the forest reserve were determined. The tree with the highest dominance Tamarindus indica (39.1) while the least is Prosopis africana (0.54). The importance value index shows that Tamarindus indica (28.67) has the highest value index while the least is Parkia biglobosa (1.90). The result of diversity of the tree species was 1.941 using Shanno’s diversity index which indicates uncertainty of the species in the study area. Therefore, there is need for urgent concerted management and policy actions which are geared towards monitoring the health and integrity of Girei forest reserve such it can continue to generate ecosystem services which are beneficial to the present and future generations.

Changes in floristic composition, diversity and anthropogenic perturbations in an east African tropical forest

AbstractWe assessed changes in floristic composition, diversity and anthropogenic activities in an East African forest; Echuya Central Forest Reserve (ECFR). Using 272 permanent sample plots, comparisons between 2015 and 2021 were made. Twenty‐two tree species were recorded with Macaranga capensis being the most dominant. Tree species density increased significantly from 152 stems/ha in 2015 to 306 stems/ha in 2021. Similarly, trees basal area increased significantly from 19 m2/ha in 2015 to 38 m2/ha in 2021. The bamboo stem density decreased significantly from 11,931 stems/ha in 2015 to 1807 stems/ha in 2021. Shrubs, lianas, vines and herbs' densities did not show significant differences between 2015 and 2021. Furthermore, a number of human activities significantly increased from 22 activities per hectare in 2015 to 83 per hectare in 2021. The Non‐Metric Multidimensional Scaling (NMDS) ordination shows that the human activities with the strongest impact on tree species composition and basal areas were fuelwood collection, human trails, livestock grazing and pole cutting. In conclusion, ECFR is floristically poor; secondary forest tree species are replacing the bamboo forest and human activities could be negatively affecting the ECFR flora. We recommend interventions of increasing people's livelihood incomes to decrease their dependence on forest resources.