Issues

This study represents analysis of abiotic forest disturbance in mountainous mixed forest, based on change detection and statistical analysis from C-band Synthetic Aperture Radar (SAR) multitemporal SAR data, provided from ESA’s Sentinel-1 satellite mission. Statistical means from the backscatter coefficients in both polarisations were calculated, with the dual-pol Radar Vegetation Index (dRVI), applying change detection before and after the disaster event. Study period was the summer of 2020 and 2021. The proposed methodology was tested at the Training and Experimental Forest Range of ‘Petrohan’ hosted by University of Forestry – Sofia. Mean estimates from SAR descriptors with emphasis on dRVI sowed high sensitivity to the forest type. The calculated differential orbit-averaged SAR descriptors utilised in change detection analysis, exhibited correlation with the optical Enhanced Vegetation Index 2 (EVI2), with highest sensitivity being the cross-pol Gamma-Nought (∆γV0H). The conducted statistical analysis has demonstrated significant differences in backscatter mean values, with the highest sensitivity observed among the three differential SAR descriptors again being the (∆γV0H). However, clear identification of the disturbances via SAR descriptors was not possible, primarily due to the mechanism of the disaster event (stem breakage) that resulted in an increased dihedral scattering. Accuracy was also influenced by the geometric distortions due to mountainous relief, which biased the SAR measurements. In conclusion, statistical analysis of multitemporal SAR is well utilised in studying forest disturbances on mixed coniferous mountainous forest. Results suggest need for an in situ data and high-resolution quad-pol POL-SAR measurements in a stem breakage disturbed forest.

Received: 07 December 2023 / Accepted: 29 April 2024 / Available online: 14 May 2024

Open Access: This article is licensed under a Creative Commons Attribution 4.0 International License. 

The article analyses the ultrastructure and morphometric characters of cells and stomata on the adaxial and abaxial surfaces of leaves in Populus deltoides Bartr. ex Marsh., Populus trichocarpa Torr. & A. Grey, Populus suaveolens Fisch. and Populus nigra cv. Italica (Du Roi) Moench (Salicaceae). The aim is to identify species-specific and diagnostically significant features at different taxonomic levels under introduction conditions. For the ultrastructure investigation, the middle part of the leaf blade was fixed on brass stubs, coated with a thin layer of gold and examined using a scanning electron microscope. Most important features are shape, size, nature of the leaf surface and the presence of specific structures. The density of epidermal cells and the number of stomata on the adaxial and abaxial surface of the leaf were determined. The hypostomatous leaf type and collenchymatous ultrastructure type were identified in P. trichocarpa and P. suaveolens, while the amphistomatous leaf type and stomato-faveolus ultrastructure type are observed on both leaf surfaces of P. deltoides and on the adaxial leaf surface of P. nigra cv. Italica. Morphometric traits of the leaf surface indicate a higher density of adaxial epidermal cells in P. nigra cv. Italica, P. suaveolens and P. trichocarpa compared to the abaxial surface. Structural organization of the leaf in P. deltoides, P. nigra cv. Italica, P. suaveolens and P. trichocarpa allows to identify these taxa on the basis of micromorphological features and suggests their broad ecological plasticity.

Received: 06 February 2024 / Accepted: 29 April 2024 / Available online: 14 May 2024

Open Access: This article is licensed under a Creative Commons Attribution 4.0 International License.

Aboveground litterfall plays a key role in carbon and nutrient cycling in forest ecosystems. In this study, data are obtained about basic aboveground litterfall parameters and quantity of common beech (Fagus sylvatica L.) in Vitinya permanent sample plot for intensive monitoring. The litterfall was sampled and assessed in three individual fractions – foliar fraction (F), wood fraction (W) and fruits and seeds fraction (FS). It was established that annual total biomass of aboveground litterfall varies in wide range from 390 up to 787 g·m-2. The most dynamic fluctuations in the quantity are found in the F fraction of total biomass that falls annually on the soil surface. For 2022, the average amount of F fraction was 363 g·m-2, which represents 59 % of the total biomass of litterfall. The reaction of litterfall in the studied fractions for the observed period remains in the acidic spectrum. In the individual fraction’s concentrations of basic cations, such as calcium and magnesium, are assessed as low. The obtained data show increasing trend of trace elements, such as iron, manganese, copper, and cadmium in F fraction. Very high concentrations of manganese and cadmium were found in all fractions of the aboveground litterfall. For manganese the average value in F fraction was 4373 µg·g-1 and for cadmium in FS fraction – 388 ng·g-1. Both obtained concentrations exceed the upper limit of these elements specified in the ICP Forests Manual for common beech litterfall fractions.

Received: 12 March 2024 / Accepted: 07 May 2024 / Available online: 14 May 2024

Open Access: This article is licensed under a Creative Commons Attribution 4.0 International License.

The root endophytic fungi coexist in a mutualistic relationship within their host plants. This study aimed to analyse the complex relationships between these plants and their fungi, revealing insight into the abundance of microbial communities living in the root systems of distinct Pteridophyte species inside this protected environment in the Gunung Tukung Gede Nature Reserve, Indonesia, and explore the potential functional roles of these fungal communities in the ecosystem. The research was carried out between July 2022 and January 2023. The roots of Pteridophyta were sampled randomly from three stations. The environmental variables examined were temperature, soil pH, moisture, and light intensity. The fungi were isolated and cultured in the PDA medium, which could then be identified. There were eight genera of root endophytic fungi: Aspergillus sp., Trichoderma sp., Phoma sp., Phialophora sp., Penicillium sp., Paecilomyces sp., Humicola sp., and Fusarium sp. In the designated conservation zones, this mutualistic connection contributes to the preservation of ecosystem health and biodiversity by being essential to Pteridophyta’s resilience and intake of nutrients.

Received: 10 November 2023 / Accepted: 05 June 2024 / Available online: 11 June 2024

Open Access: This article is licensed under a Creative Commons Attribution 4.0 International License. 

This study aims to determine the oleoresin activity of Baeckea frutescens L. against the fungus Pleurotus ostreatus (Jacq. ex Fr.) P.Kumm. and to analyse its most active component. The research method used was ethanol solvent maceration extraction, and then fractionation was carried out using successive solvents, namely n-hexane, chloroform, and ethyl acetate. Then the P. ostreatus antifungal test, and analysis of the most active compound components using Gas Chromatography-Mass Spectrometry were applied. The results showed that B. frutescens oleoresin produced a yield of 11.41 % in ethanol extract. The most active antifungal activity was found in ethanol oleoresin soluble oleoresin with IC(50) = 177 ±02 mg∙L-1. It contains 21 bioactive compounds consisting of 4 antifungal components, namely quinic acid, α-terpineol, linalool, and 2-cyclohexen-1-one.

Received: 30 January 2024 / Accepted: 06 June 2024 / Available online: 14 June 2024

 Open Access: This article is licensed under a Creative Commons Attribution 4.0 International License.