Forest stands in a regeneration class – a management−planning point of view
Drzewostany w procesie odnowienia – kontekst planowania urządzeniowego
Abstract: A forest management unit (FMU) is a management−planning unit containing stands distinguished in terms of their similar production possibilities (e.g. on account of site type). In Polish forestry, the shelterwood FMU category groups together stands managed using a uniform shelterwood cutting system, group cutting, and a stepwise cutting system (with a regeneration period of up to 40 years). However, the forecasting of stand development in FMUs of this type proves more difficult than in clear−cutting FMUs, due to the presence of stands with young−generation trees (formally assigned to classes ‘in regeneration’ or ‘with regeneration to be improved’). Such stands transition into one of the lower age classes depending on the age of regeneration after the clear−up cuts, but thus far there has been uncertainty as to the probability of the regeneration process completion (when the last cut is completed and regeneration layer covers presumed area), and as to the aspects that might make such completion more or less likely. Hence the work detailed here, which has sought to determine the nature of influences on the probability of the regeneration process being completed, as well as the dependence of that on type of cutting. The data put to this use were collected by Poland’s Forest Management and Geodesy Bureau in line with the Forest Management Instruction, in respect of 64 Forest Districts located within 14 of Poland’s 17 State Forests’ Regional Directorates, and with a view to forest management plans being developed and made available by the Directorate General of the State Forests . More specifically, data from plans elaborated in 2009 and 2010 were used, as were (in essence) repeat−data from plans elaborated for the same Districts 10 years later – in 2019 and 2020. The degree to which regeneration processes could be considered completed was then estimated empirically by overlaying the vector map of stands of Forest Districts with a 100×100 m grid of sample plots. Probabilities were calculated using logistic regression in line with type of cutting applied (uniform, group or stepwise), and the mean age or mean height of trees in the regeneration layer, along with assumed regeneration periods (of up to or more than 10 years). The relationship between the mean heights and mean ages of trees in the regeneration layer was checked, with the calculated probability then used to develop theoretical distributions of stands in age classes of the regeneration layer and height classes of young trees, with these then set against the distributions determined empirically. In the event, no correlation was found between the maximum age/height of trees in the regeneration layer or the age/height of the dominant tree species in the regeneration layer (where dominant means those present in the highest proportion), on the one hand; and the probability of the regen eration process being completed, on the other. Also looked for, though not confirmed, was an influence on completion of the regeneration process exerted by closure and dominant tree species in the upper storey, and degree of cover of the stand area achieved by the regeneration layer. In turn, completion of the regeneration process was shown to be influenced by the average age and height of trees in the regeneration layer.
Key words: cutting, group, layer, shelterwood, stepwise, tree, unit, young
Long−term tree mortality patterns in the natural forest stands of Białowieża National Park in northeast Poland
Główne wzorce i prawidłowości wieloletniego procesu zamierania drzew w naturalnych drzewostanach Białowieskiego Parku Narodowego w płn.−wsch. Polsce
Abstract: Natural tree mortality is an important element of the long−term dynamics of strictly protected forest stands. This study aimed to analyse tree mortality patterns in Białowieża National Park over a 80 year period (1936−2012) using an extensive data set from five permanent sample plots (total area=15.44 ha, a sample of ca. 10,000 trees with DBH≥5 cm × 6 census intervals). Mean annual mortality rates for particular tree species for the whole study period ranged between 1−3% · y–1. The smallest (ca. 1% · y–1) values of mortality rates occurred for hornbeam and pine, and the largest (ca. 3%· y–1) for aspen, birch, ash and spruce. The mortality rates varied significantly between census intervals, suggesting the occurrence of two basic types of mortality, i.e. regular (baseline) and catastrophic mortality. While the regular mortality was clearly the most prevalent, episodes of catastrophic mortality occurred as well (for ash, elm, spruce, aspen and birch trees). For the smallest trees (5−15 cm DBH) a strong, negative correlation between mortality rates and the degree of shade tolerance was observed (the lower the tolerance, the higher the mortality rate). In general, trees representing intermediate diameter classes were distinguished by lower values of mortality rates than the smallest and largest trees. The average residence time, calculated from mortality rates, varied strongly among individual tree species (from ca. 30 years for aspen, birch, ash and spruce to ca. 90−100 years for pine and hornbeam, for trees with DBH≥5 cm). Similarly, there were large differences between tree species in respect to the estimated length of time period needed to allow a recent population density to decline below an arbitrary threshold value of 1 ind.· ha–1. The value of this parameter was extremely low for aspen (only 3 years). For the remaining species it varied from ca. 60 years for birch to ca. 600 years for hornbeam. In future studies, an attempt should be made to elucidate the impact of the mortality type (regular vs. catastrophic, or dispersed vs. clumped) on the basic parameters of the recruitment process (composition, intensity). In addition, extending the current methodology of field work by including the most probable causes of tree mortality would help to understand better the underlying mechanisms of the long−term dynamics of natural forests.
Key words: catastrophic mortality, life history strategy, long−term study, mortality rate, permanent plot, tree population dynamics, regular mortality
Influence of endozoochory and stress conditions on the germination of black cherry Prunus serotina Ehrh. seeds outside the natural range
Wpływ endozoochorii i warunków stresowych na zdolność kiełkowania nasion czeremchy amerykańskiej Prunus serotina Ehrh. poza naturalnym zasięgiem jej występowania
Abstract: One of the most invasive species in European forest ecosystems is black cherry Prunus serotina Ehrh. Although its ecology, invasiveness mechanisms and control methods have attracted considerable forest scientists interest, some issues related to the germination capacity of black cherry seeds require further clarification. Therefore, the aim of this study was to analyse the germination of various seed variants. The study was conducted in 2019−2022. Black cherry seeds were collected in September 2019 from badger faeces and standing trees. In total, 192 seeds were used for one variant of the experiment. Observations were made every two weeks from the appearance of the first black cherry seedlings. A Pearson’s chi−squared test was used to analyse the probability of germination within a particular treatment. The total number of seeds germinated was 652 (34% of all seeds sown). The highest total share of black cherry seed germination in 2020 was observed in the seeds from badger faeces (65.1%), and the lowest in seeds that were frozen at –70°C (1.04%) and at –18°C (4.17%). In 2021, the highest total share of black cherry seed germination was observed in seeds incubated at 40°C (13.02%), and the lowest in those that were frozen at –70°C (0%). The number of seedlings in 2020 was much lower than in 2021; not a single black cherry seedling appeared in 2022. Endozoochory increases the invasiveness of black cherry. The pericarp inhibited germination, but only when the seeds in the pericarp were frozen. Black cherry seeds lying in the soil retain their germination capacity for two years.
Key words: badger, invasive alien species, Prunus serotina, seed bank, seed viability
Evaluation of the effectiveness of selected herbicides in controlling the young generation of black cherry Prunus serotina Ehrh.
Ocena skuteczności wybranych herbicydów w zwalczaniu młodego pokolenia czeremchy amerykańskiej Prunus serotina Ehrh.
Abstract: The methods of control of invasive alien species, such as the black cherry, includes the spraying of such species with herbicides. In forestry, preparations based on glyphosate salts as active substance are used to control black cherry. Due to concerns about the carcinogenicity of glyphosate, which is a threat to human health and the environment, this active substance faces the prospect of being withdrawn from use. The aim of the study was to assess the possibility of controlling young black cherry specimens by the spraying of selected herbicides representing various action groups according to the HRAC (Herbicide Resistance Action Committee) classification. In the experiment 14 herbicides (variants H1 – H14) were tested. The studies compared the effectiveness of 12 herbicides that did not contain glyphosate salts (H1−H9, H11 and H13−H14) and two that contained glyphosate salts (H10 and H12). Among the herbicides used in the experiment, there were a total of 18 active substances and they belonged to five HRAC classification groups. It was assumed that the herbicides used would be characterized by similar effectiveness to a preparation based on glyphosate salts. The research was carried out in the forest nursery of the Podanin Forestry District, where spraying was carried out on a plot with black cherry in two successive growing seasons. A five−point scale (0−4) was used to assess the effectiveness of the herbicides, where 0 indicated the plant did not respond to the treatment and 4 indicated the plant died. It was found that some of the herbicides used were similarly effective in combating young black cherry to the herbicide containing glyphosate. In the group of herbicides that resulted in 100% mortality in black cherry, there were four that did not contain glyphosate (variants H2, H5, H6, H14). Potential usefulness in the fight against black cherry was shown by active substances that were pyridine carboxylic acid derivatives (fluroxypyr – H5, triclopyr – H5), sulfonylurea derivatives (flazasulfuron H2, mesosulfuron−methyl H6, H14, thifensulfuron−methyl – H14), tribenuron−methyl – H6) and triazolopyridine derivatives (florasulam – H6). Glyphosate−containing herbicides used for the chemical control of black cherry in forestry can be replaced with non−glyphosate alternatives. The prospect of a future ban on the use of glyphosate−containing herbicides in the European Union should lead to the emergence of alternative plant protection products that are safe for humans and the environment, and effectively combat species with high invasive potential. Further studies should assess the impact of the above−mentioned herbicides on forest flora and fauna and soil biota, and in particular the procedure of approving them for use in forestry.
Key words: chemical methods of weed control, forest practice, invasive species, plant protection, silviculture
GPR (Ground Penetration Radar) research in forest areas to identify archaeological sites (Mount Ślęża, Poland)
Zastosowanie metody georadarowej (GPR) do badań obiektów archeologicznych na terenach leśnych (góra Ślęża, Polska)
Abstract: The register of archaeological remains in forests is one of the important elements hindering the optimal planning of forest management, especially in key areas from the point of view of cultural heritage. In areas managed by the State Forests National Forest Holding, archaeological sites may need to be precisely described in the registers. This may make it difficult for forest services to plan appropriate forest management. Numerous finds and archaeological sites have been inventoried on Mount Ślęża. However, detailed research is needed to identify the archaeological sites accurately. The GPR method is one of the most effective tools enabling a quick and non−invasive inventory of archaeological objects. The paper presents the research results on two objects in the State Forests on Mount Ślęża: a hill and a forest road. GPR equipment was used in the MALÅ Ground Explorer (GX) HDR. Based on field prospection and GPR measurements of the hillock in the forest and the forest area adjacent to it, various permittivities of the mediums were observed. The results indicate that the tested object is anthropogenic. The applied GPR methodology has also proven itself in studying a forest road with a rock cobblestone surface in some places. GPR echograms, however, showed that most of the pavement surface is covered with a layer of soil. Based on the obtained 2D images, it was found that the georadar can be successfully used to recognize archaeological objects in forests. It is also advisable to conduct research in the 3D system.
Key words: archaeology, forests, GPR
Assessing the growth of pedunculate oak trees from Polish provenances and families on the ‘Chrostowa II' experimental trial after 22 years
Ocena dębu szypułkowego polskich proweniencji i rodów po 22 latach wzrostu na powierzchni doświadczalnej „Chrostowa II”
Abstract: Studies were conducted on the progeny of pedunculate oak trees at an experimental trial located in the Brzesko Forest District in southern Poland. The study aimed to compare the adaptability of oak trees from 58 different trees, grown in five provenances across Poland, to new environmental conditions after being transplanted to the experimental trial situated in the Carpathian Foothills. The height and breast height diameter of the trees and calculated their slenderness quotient and basal area were measured. The research determined the range of interprovenance and intraprovenance variability and established the provenance and family heritability for each trait. The results showed that oak trees from the Krotoszyn provenance in the Kalisz Highlands had the highest values for growth traits such as height, breast height, and basal area, while the oaks of the Młynary−1 and Młynary−2 provenances from the northern part of the country had the lowest values. The provenance had a significant effect on the variation in height, breast height diameter, and basal area of the pedunculate oak. Moreover, the family had a significant effect on the latter two traits. The study also revealed that almost all oaks growing in the experimental trial had good stability, as indicated by their slenderness coefficient. The provenance heritability for all traits ranged from 0.80 for height to 0.21 for slenderness quotient. Meanwhile, the family heritability was slightly lower, ranging from 0.15 for tree height to 0.60 for the basal area. These high heritability values demonstrate the potential for the effective selection of oak trees at the provenance and family levels.
Key words: basal area, breast height diameter, height, heritability, Quercus robur