Earticle

This study was conducted to evaluate forest health and biodiversity by investigating the distribution and diversity of beetles (Coleoptera) on Mount Georyu, Goseong-gun. Beetles were sampled at different altitudes (100-500 m) on the southern and northern slopes between April and September 2024 using pitfall traps, sweeping, and direct collection. A total of 1,284 individuals belonging to 40 species and 13 families were collected. The dominant species was Propylea japonica (14%) followed by Coccinella septempunctata (10%). Seasonal analysis revealed the highest abundance in June (273 individuals) and May (245 individuals). The highest abundance was observed at 100 m (352 individuals), and declined with increasing altitude. The northern slope (796 individuals, 33 species) showed higher abundance and species richness and abundance than the southern slope (488 individuals, 26 species). The diversity index (H ’) was slightly higher on the north slope (1.325) than on the south slope (1.268). The similarity index between the two slopes was 64%. These results suggest that vegetation structure and microclimate differences between slopes and altitudes substantially affected beetle assemblages on Mt. Georyu.

Gaps created due to harvesting is expected to support the regeneration of native plant species. But it is widely criticized that regeneration felling under the shelterwood system promotes the monoculture of Shorea robusta, as its dominancy is very high in the regeneration layer. In this context, this study measured the plots with regeneration felling (managed plots) and nearby unmanaged plots to assess the differences in plant species richness and density in regeneration layers, and analysed with the canopy of managed plots before the harvesting. The results suggest that shelterwood system increases plant species richness and regeneration density, but lowers Shannon Diversity Index due to the dominance of S. robusta individuals. It also confirms that canopy opening enables regeneration to establish as sapling promoting both species richness and density at sapling layers. It informs that recent canopy openings promote the regeneration of light demander species and their colonization. When individuals gain certain heights, it influences the penetration of light in the forests floor and promote the regeneration of shade tolerant and moderately shade tolerant species. Hence, species richness increases with the age of gaps as it creates multiple layers.

Heavy metal contamination in the environment poses significant ecological and health risks, particularly in industrial regions. This study investigates the accumulation of heavy metals (Cu, Zn, Pb, Cd, and Mn) in Teak (Tectona grandis) plantations to evaluate its potential as a bio-indicator and phytoremediation agent. Soil (topsoil and subsoil) and plant (leaf and bark) samples were collected between September 2016 and July 2018 from an industrially influenced site and a background control site. Results indicate significant variation (p≤0.01) in heavy metal concentrations across different sample types, with the highest accumulation consistently observed in topsoil and subsoil. The order of metal abundance in the soil followed Mn＞Zn＞Cu＞Cd＞Pb, while plant tissues exhibited Zn and Cu as the dominant elements. The highest Cu and Zn concentrations in plant samples were recorded in bark, suggesting atmospheric deposition as a contributing factor. Lead (Pb) levels, though detected in all sample types, remained below the phytotoxic threshold. Statistical analyses revealed that industrial emissions and vehicular activity played a crucial role in metal distribution patterns. The findings suggest that while Teak exhibits limited heavy metal accumulation in its tissues, it could serve as an effective bio-indicator for environmental pollution monitoring. Further research is recommended to assess the long-term impact of metal accumulation on Teak growth and its potential application in phytoremediation strategies.

The study assessed the willingness of stakeholders (sawyers, plank sellers, and forestry department staff) to participate in private forest plantation establishment in Ilorin, Kwara State, Nigeria, using a purposive sampling design. A total of 150 questionnaires were administered across the stakeholder groups. Data were analysed using descriptive and inferential statistics at α=0.05. Findings revealed that most respondents were willing to participate in private forest plantation establishment due to its economic benefits (Sawyers=74%, Plank Sellers=82%, Forestry Staff=66%). While perceptions varied among stakeholder groups, lack of capital (Sawyers, x̄=3.36; Plank Sellers, x̄=3.26; Forestry Staff, x̄=3.16) and limited access to loans (Sawyers, x̄=3.18; Plank Sellers, x̄=3.46; Forestry Staff, x̄=3.02) were major constraints. Significant associations were observed between willingness and socio-demographic or experiential factors. Gender influenced willingness among sawyers (χ2=3.742) and forestry staff (χ2=5.451). Knowledge of plantation establishment was significant for sawyers (χ2=11.435) and plank sellers (χ2=13.490), while experience influenced sawyers (χ2=5.348). Membership in environmental organizations was positively associated with willingness among plank sellers (χ2=9.350) and forestry staff (χ2=8.336). The results underscore the need to improve access to capital, provide an enabling environment, and create awareness on the importance of private forest plantations. The interventions can enhance stakeholder participation, support sustainable forest management, and contribute to economic and environmental development in the study area.

This paper examined different 2-parameter and 3-parmeter nonlinear models for height-diameter prediction that incorporated different stands variable for the development of robust generalised height-diameter models. Stratified random sampling was employed in selecting 54 sample plots (20 m by 20 m) for six different age series (6, 9, 13, 15, 17 and 21 years old) plantation. Diameter at breast height (D), total height (h) and merchantable height (hm) for individual trees with D≥10 cm were measured. The Nonlinear model forms were fitted by ordinary nonlinear least square (ONLS) regression to select the base model without random parameters. Stands variables where then incorporated as random components for mixed-effects modelling using Gauss-Newton algorithm for nonlinear (weighted) least-squares. The best models were adjured using Standard error of estimate (SEE), Root means square (RMSE) and Akaike’s Information Criterion (AIC) and validated by Z-Score values and residual plot. The overall best height-diameter prediction equation for 2-parameter and 3-parameter estimate was Meyer function and Logistic models respectively. All the parameters of the models predicted at p＜0.05 are significant justifying the use of this model for future predictions in the study area expect for Prodan model. The nonlinear mixed effects yield model developed are efficient and biologically logical in predicting yield of teak in the study area, therefore enabling forest managers to optimise harvest planning, plantation regeneration and management in Area J4 of Omo Forest Reserve.