Deep soil ploughing for afforestation: a review of potential impacts on soil and vegetation

Deep ploughing—which inverts, covers, or mixes soil organic layer (forest floor) and surface mineral A horizon into the mineral subsoil, burying the upper soil horizon in deeper layers, and disrupting pedogenic processes—is a debatable topic in forest plantation management. Overall, this review article aimed to identify the impacts of deep ploughing on the properties of forest plantations, adapting experiences from the agricultural sector. This paper examines the main impacts of deep ploughing technology on soil physical, chemical, and biological properties, ground vegetation, and tree aboveground and belowground biomass in afforested former agricultural land. Analysis of the published literature shows that deep ploughing can be used under different climatic and soil conditions, but it induces site-specific changes in soil properties and vegetation. Mechanical site preparation during afforestation and reforestation should follow the requirements of sustainable soil management, in order to avoid negative effects on the environment and biodiversity. Based on this analysis, we suggest key indicators that may be specific to deep ploughing responses in afforested sites and can contribute to risk assessment, aimed at achieving sustainable forest management. To date, most studies on mechanical site preparation for forest plantation have been performed using a few conifer tree species; therefore, it is important to expand empirical studies.

The frequency method in studying habitat preferences of common forest birds

This paper presents the results of a study on the habitat preferences of selected species of the bird community in the Morgi Forest, the Kolbuszowa Forest Division (SE Poland), with the use of the point-stand bird census method. The aim of the study was to test the effectiveness of the method in determining the frequency of colonisation of stands with different habitat parameters by the most abundant bird species. In 270 tree stands of a forest complex with diverse habitats, a bird census was carried out with four counts per each stand. Next, a list of the tree stands and the bird species recorded in the stands was compiled. The stands were divided into categories according to the forest habitat type, dominant species and age class. In the next step, the occurrence frequency of the most abundant bird species was calculated for each stand category. Among the analysed species, the majority showed a positive correlation between the frequency of occurrence and habitat fertility. The influence of the dominant stand species on the occurrence frequency of bird species was largely driven by habitat fertility. The lowest average frequency of the identified avian species was found in stands dominated by pine Pinus sylvestris, birch Betula sp. and black alder Alnus glutinosa. There was generally a positive relationship between age class and the bird community parameters. It is concluded that the point-stand method of bird census provides informative results for research on the habitat selectivity of bird populations.

Female forest owners as a market segment? Results from a marketing experiment in the context of a small forest service enterprise

Broad social changes are reflected in the forest owner structure, which has become increasingly diverse both demographically and in terms of objectives and values. This naturally also impacts forest owners’ interest towards using their forests as well as to their interest in purchasing various forest management services. This development highlights the need for service providers to better segment their clientele and plan their market communication accordingly. However, a surprisingly small amount of research has focused on the impact of marketing arguments for various forest owner segments. This study provides a first attempt to analyse, through a real-life marketing intervention, how effective marketing arguments are at promoting first thinning to female forest owners. For this, three marketing messages were created and sent out to 300 forest owners in Finland. One message explained the importance of first thinning to provide maximal economic income from forests, one explained the importance of first thinning in relation to biodiversity protection and climate change mitigation, and a control message included no value arguments. The results indicate that contrary to our hypothesis, the marketing message with the economic arguments raised more interest towards the first thinning service among female forest owners than the one with biodiversity protection and climate change mitigation values. The results further show that the control message was found to generate the least interest towards first thinning. This indicates that incorporating value arguments do improve the impact of a marketing message. Key words Market segmentation, female forest owner, marketing argument, economic values, biodiversity values

Estimation of litter input in hemi-boreal forests with drained organic soils for improvement of GHG inventories

Assessments of net greenhouse gas (GHG) emissions in forest land with drained organic soils conducted within the scope of National GHG inventories requires reliable data on litter production and carbon (C) input to soil information. To estimate C input through tree above-ground litter, sampling of above-ground litter was done in 36 research sites in Latvia representing typical forests with drained organic soils in hemiboreal region. To estimate C input through tree below-ground litter and litter from ground vegetation, modelling approach based on literature review and data on characteristics of forest stands with drained organic soils in Latvia provided by National Forest Inventory (NFI) was used. The study highlighted dependence of C input to soil through litter production from the stand characteristics and thus significant differences in the C input with litter between young and middle age stands. The study also proves that drained organic soils in middle age forests dominated by Silver birch, Scots pine and Norway spruce may not be the source of net GHG emissions due to offset by C input through litter production. However, there is still high uncertainty of C input with tree below-ground litter and ground vegetation, particularly, mosses, herbs and grasses which may have crucial role in C balance in forests with drained organic soils. Key words: forests, drained organic soils, litter production, carbon input, National GHG inventory

Trends of Scots pine forest health and element flow changes in the ICP Forests monitoring sites in Latvia

Scots pine (Pinus sylvestris L.) is one of the most widespread and economically most important tree species in Latvia. Scots pine forest health and element flow changes have been monitored in Latvia within the International Cooperative Programme on Assessment and Monitoring of Air Pollution Effects on Forests (ICP Forests) with assessment of crown condition and damaging agents at 115 Level I monitoring sites (mostly oligothrophic and mesotrophic Vacciniosa, Myrtillosa and Hylocomiosa forests) and with sampling and analyses of environmental samples at three Level II monitoring sites representing typical Scots pine forests (Myrtillosa) in hemiboreal conditions in Latvia. This study summarizes the background information and presents the trends of forest health, carbon turnover and environment condition in Scots pine forest since 2009. In general, defoliation rate in Scots pine stands remains stable for the studied period, with some yearly fluctuations, possibly related to regional insect outbreaks, especially well demonstrated in two Level II plots. The share of damaged trees varied by year from 12.8% to 19% of the total number; the main cause of damage was direct action of man. Chemical element flows in Scots pine forests in Level II monitoring plots have been relatively stable as well except the decreasing trend in total N concentration in deposition and SO4-S concentration in soil solution and increasing trends in DOC concentration in soil solution that is in line with common trends in Europe. Carbon input with above-ground litter was relatively stable during the whole period; however, interannual variations were rather wide.

Morphological variability of Douglas fir (Pseudotsuga menziesii (Mirb.) Franco) cones in the context of seed extraction

In the paper generating curves given by fourth-degree polynomials were used to model the shape of Douglas fir (Pseudotsuga menziesii (Mirb.) Franco) cones from the Polish Forest Districts of Kołaczyce (one batch) and Opole (two batches), and to calculate the surface area and volume of individual cones. However, it was not possible to construct generalized equations for the surface area and volume of Douglas fir cones due to the high variability of empirical coefficients. The surface area and volume of the cones were also calculated from their length and diameter based on formulas for a cylinder and a barrel corrected by constants k1 and k2. The mean surface area of closed Douglas fir cones determined for the first, second, and third batch using the generating function was 4,348.4 mm2, 3,857.0 mm2, and 2,844.7 mm2, and the volume was 27,212.4 mm3, 21,012.9 mm3, and 12,844.4 mm3, respectively. The corresponding values calculated from the geometric formulas for solids were 4,332.0 mm2, 3,838.0 mm2, and 2,862.9 mm2 for the surface area and 27,366.0 mm3, 20,648.9 mm3, and 13,375.3 mm3 for the volume. The evaporation area of open cones was found to be five times greater than that of closed cones, with the difference being statistically significant. The outer and inner surfaces of scales taken from the middle segment of Douglas fir cones were photographed using a Quanta 200 scanning microscope (FEIC). The characteristic elements of scale morphology were evaluated by means of MultiScan Base software package. The outer and inner surfaces of Douglas fir scales were found to differ in some important ways, similarly as it has been reported in the literature for the Scots pine, silver fir, European larch, and black alder. The outer surface of scales is formed by thick-walled cells with marked protrusions, while the inner surface reveals cells with thin, frayed walls in the region adjacent to the seeds and wings. Knowledge of the geometry of Douglas fir cones and the morphology of their scales may be helpful in optimizing seed extraction parameters for those cones. Key words: seed extraction, model, shape curve, surface area, volume, scanning electron microscope

The influence of synthetic foaming agents on seed germination of coniferous species

Water is the most frequently used substance for extinguishing of wildfires. Ones of the most commonly used additives enhancing the extinguishing efficiency are foaming agents. This article deals with the influence of foaming agents on germination of coniferous species. Foaming agents Moussol-APS F-15 and Sthamex F-15, foaming solutions of various concentrations were used for the tests. Germination of seeds of Norway spruce (Picea abies) and Scots pine (Pinus sylvestris) was observed. The percentage of germinating seeds was recorded every 7 days. The results were evaluated in the form of graphs. When the concentration levels of foaming solutions ranged from 0.1 vol% to 0.25 vol%, their influence on germination of both coniferous species seeds varied from negligible to slightly positive. Subsequently, the negative effect increased considerably and with concentrations exceeding 1 vol% - 1.5 vol% the germination of samples reached zero values. While foaming solutions of Sthamex F-15 showed less significant influence on germination of the Scots pine seeds, seeds of the Norway spruce were less influenced by foaming agent Moussol-APS F-15. Based on obtained results it is possible to recommend minimisation of foaming agents amounts, eventually application of substances with less negative effect on plants germination for extinguishing of wildland fires, in order to gain restoration of affected area as fast as possible. Key words: foaming agent, germination, wildfire (wildland fire), foaming solution

Salinity and temperature influencing seed germination of Mediterranean Aleppo pine (Pinus halepensis Mill.): an ecological adaptation to saline environments

In Mediterranean basin, Pinus halepensis Mill. is the dominant conifer used in afforestation and landscape projects. The ecological, aesthetic and commercial benefits make this conifer a precious tree for both woody production and land rehabilitation. Nevertheless, detailed studies on the adaptation of this tree to abiotic environmental constraints in the Mediterranean areas remain limited up until now. Therefore, laboratory experiments were conducted to assess the effects of the interactive impact of temperatures and salinity on the germinability potential of P. halepensis seeds. The cones of P. halepensis used in this experiment were harvested from the Gotaïa forest at Djelfa province, Algeria. The seeds were removed from their cones and surface-sterilized by soaking for five min in 10% NaClO. Seeds were germinated at three temperature regimes (10–20 °C, 15–25 °C and 20–30 °C) and four levels of salinity (0, 50, 100, and 150 mM NaCl) at photoperiodic lighting (16 h of light : 8 h of dark). For each treatment 04 replicates of 25 seeds were placed in Petri dish with 5 ml of test solutions. A completely randomized design (CRD) was used for the experiment. Results revealed that the uppermost germinability was recorded in distilled H2O and the progressive enhancement of NaCl significantly (P < 0.001) suppressed germination. At 15–25 °C (dark : light thermoperiod), P. halepensis seeds showed approximately 90% of germination at 0 mM NaCl. However less germination percentage (GP) was obtained at 10–20 °C and 20–30 °C. Values of Timson’s index were also suppressed significantly (P < 0.001) with an increase under salt stress at all thermoperiods but at least at 15–25 °C. These funding suggest that seeding of P. halepensis may be an effective path for rehabilitation of degraded lands where salinity and drought are major features of the arid ecosystems. Yet, this conclusion still needs verification by field experiments. Key words: Pinus halepensis; arid zones; sowing dates; afforestation; salt tolerance

The Use of an Artificial Neural Network for Predicting the Gloss of Thermally Densified Wood Veneers

In this study, an artificial neural network (ANN) model was developed to predict the gloss of thermally densified wood veneers. A custom application created with MATLAB codes was employed for the development of the multilayer feed-forward ANN model. The wood species, temperature, pressure, measurement direction, and angle of incidence were considered as the model inputs, while the gloss was the output of the ANN model. Model performance was evaluated by using the mean absolute percentage error (MAPE), the root mean square error (RMSE), and the coefficient of determination (R²). It was observed that the ANN model yielded very satisfactory results with acceptable deviations. The MAPE, RMSE, and R2 values of the testing period of the ANN model were found as 8.556%, 1.245, and 0.9814, respectively. Consequently, this study could be useful for the wood industry to predict the gloss with less number of tiring experimental activities.

Octopus stinkhorn Clathrus archeri (Berk.) Dring, an alien stinkhorn fungus (Phallaceae), in north-eastern Poland

Distribution of an alien fungus, octopus stinkhorn Clathrus archeri, has been studied in north-eastern Poland. The closest earlier known localities of this species, situated north of the new ones, were reported near the village of Dymnica (Lębork County) in Poland and near the town of Kartena in Lithuania. Field research was conducted in May–November in 2019-2020 and information from naturalists and foresters was verified, to map this species and draw attention to the problem of appearance of alien fungal species in forests. In the locality where the largest number of basidiomata was found, they were measured every day from 12 October till 2 November 2020: height and width of young ones at the egg phase, height of mature ones, and length of their longest arms. Additionally, arms of individual basidiomata were counted. We have documented 7 localities of C. archeri, including 5 situated in forests and 2 in other habitats. In total, we found 63 basidiomata of this species. In the localities outside forests, basidiomata of C. archeri appeared in places where timber was stored and the soil was covered with sawdust and pieces of bark. The other 5 localities were situated in broadleaved forests with a small proportion of coniferous species. It seems that C. archeri, when moisture level is suitable, finds favourable living conditions in fertile broadleaved forests of north-eastern Poland. It is sometimes re-moved from forest areas (e.g. with wood) to open and urbanized areas. Considering the observed climate change, we can expect a further spread of C. archeri to the north-eastern of Poland and an increase in the number of its localities in the Baltic Sea region. Spore dispersal of this species is facilitated not only by humans but also by insects. No negative impact of C. archeri on wooded habitats was noticed. Key words: Phallaceae, Clathrus archeri, octopus stinkhorn, alien species, ecology, distribution, forest, Poland