Effects of Gap Size and Cardinal Directions on Natural Regeneration, Growth Dynamics of Trees outside the Gaps and Soil Properties in European Beech Forests of Southern Italy

The present study was focused on how cardinal directions inside gaps of different sizes (small, 200 m2; medium, 400 m2; and large, 600 m2) can affect soil characteristics and tree regeneration. Additionally, the effects of gap size on the growth dynamics of trees outside the gaps were evaluated. The study was carried out in a European beech stand located in Aspromonte National Park (Southern Apennines, Calabria, Italy). Microclimatic variables, physical, chemical, and biochemical soil properties, natural regeneration density, and growth trees outside the gaps density of natural regeneration were assessed. This study provided evidence for an important effect of cardinal points on micro-environmental parameter variability, nutrient cycle, physic-chemical soil properties, water availability, and biological processes such as trees growth and regeneration. The European beech natural regeneration was most abundant in the south part of the gaps. Thus, we can state that cardinal points affect the trees natural regeneration in a species-specific manner. The new microclimatic conditions due to the gap opening had positive effects on the tree growth located along the gap edge, especially in the trees sampled on the edges of the medium gaps. On the contrary, the trees located in the forest recorded a productivity coherent with the period prior the gap opening. In medium-sized gaps, the combination and interaction of microclimatic and soil parameters (humification and mineralization process and microbial activity) created the best conditions for beech natural regeneration and favored an increase in the productivity of the trees at the edge of the gaps.

Enzymatic Activity of Soils Forming on an Afforested Heap from an Opencast Sulphur Mine

Post-mining areas require reclamation. The main aim of reclamation is to restore the soil as a basic element of the terrestrial ecosystem. This paper presents the results of an evaluation of the enzymatic activity of soils formed on an afforested heap from an opencast sulphur mine. Six research sites were selected on the overburden heap of the Piaseczno sulphur mine, afforested 50 years ago. They differed in the type of soil in the subsoil and in the species composition of the stand. The activity of dehydrogenases, phosphatases, urease, total organic carbon, and total nitrogen was determined and statistical analysis of the obtained results showed that the activity of the evaluated enzymes in the soils formed in the reclaimed areas was significantly dependent on the type of substrate and the species composition of the plants. The activity of the evaluated enzymes was significantly positively correlated with the content of total nitrogen and the C/N ratio, and the activity of phosphatases and urease with the total organic carbon content. Within soils developed on the same texture, the influence of stand species was revealed. In soils formed on clay, the soils under the beech stand and under the birch stand were characterized by higher activity of enzymes. The soil developing under the stands of European larch and red oak was characterized by higher enzymatic activity on weakly clayey sands. On loose sands, the activity of dehydrogenases and urease was significantly higher under acacia robinia than under hornbeam.

Structure and Abundance of Fusarium Communities Inhabiting the Litter of Beech Forests in Central Europe

Members of the genus Fusarium and related genera are important components of many ecosystems worldwide and are responsible for many plant diseases. However, the structure of beech litter-inhabiting Fusarium communities and their potential role in reducing the natural regeneration of European beech are not well understood. To address this issue, we examined Fusarium communities in the litter of uneven-aged, old-growth beech-dominated forests in the Carpathians (Poland) and in the Alps (Austria), and in a managed beech stand (Poland). The fungi inhabiting beech litter were investigated using beechnuts and pine seedlings as bait. The pathogenicity of the most common species was investigated by inoculating beech germinants. Fusarium spp. were identified based on morphology and DNA sequence comparisons of RPB2 and TEF1-α genes, combined with phylogenetic analyses. Twelve fungal species were identified from 402 isolates, including nine known and three currently undescribed species. The isolates resided in three species complexes within the genus Fusarium. These were the F. oxysporum (one taxon), F. sambucinum (three taxa), and F. tricinctum (six taxa) species complexes. In addition, one isolate was assigned to the genus Neocosmospora, and one isolate could be placed within the genus Fusicolla. The most frequently isolated fungi from beechnuts and beech germinants were F. avenaceum (Fr.) Sacc., F. sporotrichioides Sherb. and Fusarium sp. B. The structure and abundance of species within Fusarium communities varied by beech forest type. The species richness of Fusarium spp. was greatest in old-growth beech-dominated stands, while abundances of Fusarium spp. were higher in managed beech-dominated stands. Pathogenicity tests showed that all four Fusarium species isolated from beechnuts and beech germinants could cause germinants to rot beech, suggesting that these fungi may play a negative role in the natural beech regeneration.

Evaluating the effect of stand properties and site conditions on the forest reflectance from Sentinel-2 time series

Forest stand reflectance at the canopy level results from various factors, such as vegetation chemical properties, leaf morphology, canopy structure, and tree sizes. These factors are dependent on the species, age, and health statuses of trees, as well as the site conditions. Sentinel-2 imagery with the high spatial, spectral, and temporal resolution, has enabled analysis of the relationships between vegetation properties and their spectral responses at large spatial scales. A comprehensive study of these relationships is needed to understand the drivers of vegetation spectral patterns and is essential from the point of view of remote sensing data interpretation. Our study aimed to quantify the site and forest parameters affecting forest stands reflectance. The analysis was conducted for common beech-, silver fir- and Scots pine-dominated stands in a mountainous area of the Polish Carpathians. The effect of stands and site properties on reflectance in different parts of the growing season was captured using the dense time series provided by Sentinel-2 from 2018–2019. The results indicate that the reflectance of common beech stands is mainly influenced by elevation, particularly during spring and autumn. Other factors influencing beech stand reflectance include the share of the broadleaved understory, aspect, and, during summer, the age of stands. The reflectance of coniferous species, i.e., Scots pine and silver fir, is mainly influenced by the age and stand properties, namely the crown closure and stand density. The age is a primary driver for silver fir stands reflectance changes, while the stand properties have a large impact on Scots pine stands reflectance. Also, the understory influences Scots pine stands reflectance, while there appears to be no impact on silver fir stands. The influence of the abovementioned factors is highly diverse, depending on the used band and time of the season.

The effects of organic matter and flooding on the ecotoxicity of pore water in soils developed in the sites of historical arsenic mining: application of biological tests with crustacean zooplankton

<p>Arsenic is a trace metalloid, potentially toxic for humans, animals and for plants. The problem of soil pollution with arsenic occurs in Poland only on a local scale, but in the Sudetes and in their foreland, there are several sites were arsenic was mined in the past. Particularly high concentrations of As in soils were confirmed in Złoty Stok, formerly the main European centre of arsenic industry. Decomposing forest litter as well as flooding can affect mobilization of As and other toxic elements, change their speciation in pore water and influence the toxicity to biota. This study examined the chemistry and ecotoxicity of pore water acquired from two soils that developed in a former As mining site: from the “Orchid dump” and from a nearby forest. Soils used in the experiment  contained very high concentrations of As: 2020 and 19600 mg/kg.  An unpolluted soil was used as a control. Soil samples were incubated in various moisture conditions (70%  of water holding capacity and 100% flooding), in the presence and absence of organic matter introduced with forest litter collected from a beech stand. Soil pore water was collected three times (after 7, 21 and 90 days) with MacroRhizon suction samplers. Chemical analysis of pore water involved the measurements of concentrations of As and potentially toxic metals, including Mn and Fe, as well as the concentrations of P. Ecotoxicity of pore water was examined in two bioassays: THAMNOTOXKIT F and RAPIDTOXKIT F. The Thamnocephalus platyurus toxicity test is a 24h bioassay based on the mortality of the test organisms (freshwater crustaceans). The sublethal effects were determined using RAPIDOTOXKIT, based on ISO standard 2011. This procedure measures the feeding inhibition of the juveniles of T. platyurus. A very high toxicity to T. platyurus was confirmed in the pore water of the soil richer in As, where all the organisms died. High mortality of crustaceans > 83,33 % was found in the pore water of soil collected from the Orchid dump, in particular after a longer incubation period. The addition of beech litter, as well as soil flooding, caused an increased mortality of test organisms that reached 100%, regardless of the time of incubation. In the pore water of less polluted soil, collected from the forest site in Złoty Stok, an increased mortality of crustaceans was observed upon the addition of beech litter. The RAPIDOTOXKIT test turned out less sensitive to high concentrations of As and other toxic components present in soil pore water. The feeding inhibition did not correspond directly with the concentrations of As. However, in the case of samples with the highest As concentration (130 mg/L), found in pore water of the Orchid dump soil treated with beech litter and fully flooded, the feeding inhibition reached 100%.</p><p>This research was funded by the National Science Centre of Poland; Project No. 2016/21/B/ST10/02221</p>

Influence of stand and terrain characteristics on the productivity of the Timberjack 240b tractor in pure beech stands

This paper presents the results of research of the Timberjack 240b tractor equipped with a double-drum winch (work form 1 Tractor driver + 0 Assistant) in beech stand at an average elevation of 983.73 m. The research was conducted using the time and work study method, with the help of GIS technology in certain segments of research. The achieved working hours consist of 75.44% effective time and 24.56% delay time. The delay time coefficient is 1.33. In total, 47 transport cycles were realized, with 66 stopping points, an average of 1.41 per transport cycle. The average skidding distance was 221.19 m. In total, 363 logs (204.04 m3) were collected by 79 winches. The average load volume was 4.34 m3 and consisted of 5.43 pieces. Loaded tractor skidding time is strongly influenced by skidding distance and load volume in interaction with the longitudinal slope of skidding trails. To increase tractor productivity, it was concluded that the skidding roads should be built with the smallest longitudinal slope possible. Preferably, logs should be skidded downhill.

Effect of Competition and Climatic Conditions on the Growth of Beech in the Mixed Pine Beech Stand: Lithuanian Case Study

Climate change and warming will potentially have profound effects on forest growth and yield, especially for pure stands in the near future. Thus, increased attention has been paid to mixed stands, e.g., pine and beech mixtures. However, the interaction of tree species growing in mixtures still remains unknown. Thus, the aim of this study was to investigate the impact of the interspecific and intraspecific competition to diameter, height, and crown width of pine and beech trees growing in mixtures, as well as to evaluate the impact of climatic indicators to the beech radial diameter increment. The data was collected in 2017 at the mixed mature pine beech double layer stand, located in the western part of Lithuania. The sample plot of 1.2 hectare was established and tree species, diameter at the breast height, tree height, height-to-crown base, height-to-crown width, and position were measured for all 836 trees. Additionally, a representative sample of radial diameter increments were estimated only for the beech trees by taking out core discs at the height of 1 m when the stand was partially cut. Competition analysis was based on the distance-dependent competition index, which was further based on crown parameters. Climatic effect was evaluated using classification and regression tree (CART) analysis. We found almost no interspecific competition effect to diameter, height, or crown width for both tree species growing in the first layer. However, it had an effect on beeches growing in the second layer. The intraspecific competition effect was important for pine and beech trees, showing a negative effect for both of them. Our results show the possible coexistence of these tree species due to niche differentiation. An analysis of climatic indicators from 1991–2005 revealed that precipitation from February–May of the current vegetation year and mean temperatures from July to September expressed radial diameter increment effects for beech trees. Low temperatures during March and April, as well as high precipitation during January, had a negative effect on beech radial increments. From 2006–2016, the highest effect on radial diameter increments was the mean temperatures from July to September, as well as the precipitation in January of the current year. From 1991–2016, the highest effect on radial diameter increments was the temperature from July to September 1991–2016 and the precipitation in June 1991–2016. Generally, cool temperatures and higher precipitation in June had a positive effect on beech radial increments. Therefore, our results show a sensitivity to high temperatures and droughts during summer amid Lithuanian’s growth conditions.

Međuovisnost različitih indikatora vitaliteta stabala i njihov odziv na klimatske uvjete na plohi obične bukve (Fagus sylvatica L.)

Interrelations of various common beech vitality indicators (crown defoliation, foliar chemistry, radial growth) as well as their possible dependencies on climatic conditions were investigated over the course of 12 years in a mature and healthy beech stand. Our results confirm the importance of temperature variables for defoliation, as high temperatures during spring and summer months induce the increase of defoliation. The same negative influence was observed with high maximum temperatures and low precipitation during previous year summer months. Phosphorus, calcium and magnesium nutrition of beech trees suffers from high temperatures during current year summer and benefits from more precipitation. High temperatures in current year May positively influence beech radial growth, while a wide range of minimum temperatures during March and June has a negative effect. In summary, high summer temperatures and low precipitation were shown to have a negative effect on all vitality indicators, and for defoliation and nutrition this effect can last into the following year.

Considerations Concerning the Oldest Stands from Banatului Mountains, Romania

The present study was realized in Banatului Mountains (Romanian Carpathians) within Nera, Caransebeș and Băile Herculane Forest Districts, based on forest management plans from 1991-2008 and has led to the identification of 394 stand elements older than 200 years. The purpose of this paper was to analyze the trees’ main qualitative characteristics (age), the stands’ structural characteristics (consistency, composition, average diameter and average height) as well as the stational characteristics (altitude, slope, soil type). The main focus was to identify the oldest stands from Banatului Mountains. The present paper presents the oldest 18 stands as well as their most representative characteristics: diameter, height, consistency, slope, altitude, soil, site and structure. The oldest stand identified in this area is a 260-year-old common beech stand from Nera with heights between 36-38 meters and a diameter of 98 meters. Furthermore, it has been observed that common beech stands have a normal consistency, while their structure is relatively uneven-age. The research has shown that the surface occupied by old common beech stands that have reached their exploitability age is of 60.978 ha, namely 13% of the total surface of these forests. The site conditions where they are spread are characterised by preponderantly Northeast and South-West expositions, fields with slopes of 21-30 degrees, average altitudes of 900-1000 m, eutric cambisol and luvisol soils and medium and superior reliability sites.