• Spatial statistics provides a quantitative description of natural variables distributed in space and time.• The objectives of spatial analysis are to detect spatial patterns and to confirm if a pattern found is significant. • Spatially explicit indices and functions may be applied depending on the information collected from the field. • Development of the specific software supports spatial analyses. AbstractThis paper presents a review of the most common methods in ecological studies aimed at spatial analysis of population structures (horizontal and vertical), based on point process statistics. Methods based on simple spatially explicit indices as well as more sophisticated methods relying on functions are described in a comprehensible manner. Simple indices revealing the information on spatial structure at the scale of the nearest neighbor can be easily implemented in practical forestry. On the other hand, spatial functions, based on much more detailed data, describe the spatial structure in terms of the spatial relationships between the natural processes and population structures and because of this complexity they are rarely used in forest practice. Including both methods in a single paper is also valuable from the potential reader's point of view saving their time for searching and choosing the appropriate method to make their spatial analysis. This paper can also serve as an initial guide for young researchers or those who are going to start their studies on spatial aspects of bio-systems. Avoiding the statistical and mathematical details makes this paper understandable for readers who are not statisticians or mathematicians. Readers will find many references related to each method described here, allowing them to find solutions to different problems observed in practice. This paper ends with a list of the most common specific software packages available to support spatial analysis.

Context Taxus woodlands suffer from a lack of natural regeneration across its whole distribution range. Aims In Knyazhdvir Reserve in Ukraine Taxus baccata primarily competes with Abies alba. It has been assumed that in the conditions of deep shade, yews have a greater competitive advantage than firs. Methods To verify this hypothesis, a plot with both species growing under the canopy was established. Wood samples were taken from 20 trees of T. baccata and 20 trees of A. alba. Results There were no differences in the mean tree-ring width, height and age between both species. Due to a lack of spatial separation of both species, yews and firs inhabited the same area in the analysed plot. Fir seedlings (up to 0.5 m) were recorded to grow under yew saplings (above 0.5 m), but the inverse situation of yew seedlings growing under fir saplings was not seen. Conclusion Seedling distribution, tree-ring growth rate, possibility of growth of fir seedlings under yew saplings and greater potential growth suggested that fir was predisposed to having the competitive edge over yew. Our results may confirm the hypothesis that T. baccata has a restricted distribution because of weak competitive abilities and can exist only in habitats where faster growing species are absent. The results call into question the prevailing opinion that human influences are the principal cause for the decline of T. baccata.

alder and common birch, the initial aggregated pattern was maintained over the examined 14-year period of the forest succession. Bivariate analysis showed that the most common interspecific association between pairs of tree species was spatial segregation (pine vs. alder, alder vs. birch and oak vs. birch) followed by spatial independence (pine vs. oak and oak vs. alder). The positive association was stated only for pine and birch and only for certain spatial scales (> 5 m). Simultaneously, at small distances they showed reciprocal repulsion. Changes in spatial relationships between tree species were negligible over 14-year period of forest succession. Our results confirmed the density-dependent mortality process in the uneven-aged Scots pine-dominated forest over 14-year period of forest development. Our study showed that spatial interactions between individuals along with speciesspecific ecological requirements should be incorporated into realistic models of forest development, helping to manage the forest ecosystems toward their greater structural complexity.

Experiments testing multiple factors that affect the rate of invasions in forests are scarce. We aimed to assess how the biomass of invasive Prunusserotina changed over eight years and how this change was affected by light availability, tree stand growth, and propagule pressure. The study was conducted in Siemianice Experimental Forest (W Poland), a common garden forest experiment with 14 tree species. We investigated aboveground biomass and density of P.serotina within 53 experimental plots with initial measurements in 2005 and repeated in 2013. We also measured light availability and distance from seed sources. We used generalized additive models to assess the impact of particular predictors on P.serotina biomass in 2013 and its relative change over eight years. The relative biomass increments of P.serotina ranged from 0 to 22,000-fold. The success of P.serotina, expressed as aboveground biomass and biomass increment, varied among different tree species stands, but was greater under conifers. Total biomass of P.serotina depended on light and propagule availability while biomass increment depended on the change in tree stand biomass, a metric corresponding to tree stand maturation. Our study quantified the range of invasion intensity, expressed as biomass increment, in a forest common garden experiment with 14 tree species. Canopy cover was the most important variable to reduce susceptibility to invasion by P.serotina. Even a modest decrease of overstory biomass, e.g. caused by dieback of coniferous species, may be risky in areas with high propagule pressure from invasive tree species. Thus, P.serotina control may include maintaining high canopy closure and supporting natural regeneration of tree species with high leaf area index, which shade the understory.

Fine-scale spatial genetic structure (SGS) has profound ecological and genetic consequences for plant populations, and some studies indicate that clonal reproduction may significantly enhance SGS. Clonality is widespread among dioecious species, but little is known about the relationship between clonal reproduction and SGS in the frame of sexual dimorphism. We asked the following questions: (1) Is there a sexually dependent pattern of SGS in white poplar population? (2) What is the relationship between clonal reproduction and SGS? and (3) Does this relationship have a sex-specific component? Using 16 microsatellite markers, genetic structure including fine-scale SGS and clonality of females and males of white poplar were investigated. Significant SGS was noted for both sexes at the ramet and genet levels. At the genet level, males had 2.7-fold higher SGS than that of females. Clonality significantly contributed to SGS only in females. A sibship structure revealed with pedigree analysis and clustering-based methods among males was likely the major factor of the observed SGS. The sexes differed in their clonal growth strategies. Spatial positioning of ramets in female clones suggested foraging behavior and/or avoidance of competition, while for male clones it indicated more expansion and space colonization. The obtained results led us to conclude that sexual dimorphism in life history traits may affect the course and rate of demo-genetic processes acting in natural populations of dioecious species. To our knowledge, this is the first study demonstrating a sex-specific pattern of SGS in natural populations of dioecious species.

No abstract

We examined the spatial diversity of young growth established after the catastrophic windthrow occurred in 2002 in the northeastern part of Poland. Our observations and measurements were conducted on permanent circular measurement plots located in the Szast Protected Forest (continental lowland temperate forests) that were established 3 years after the windstorm and left to natural succession. We evaluated the spatial indices characterizing the four main aspects of stand structure: the spatial arrangement of seedlings and saplings, species mingling, tree size diversity at the local spatial scale and the overall structural complexity index. The calculations were conducted in parts of the forest with differing severity of disturbance. The obtained results indicated the prevalence of a random arrangement of young growth. Clumps of regeneration were observed to a lesser degree in all parts of the forest. The species diversity was moderate and was the highest in the slightly or severely disturbed stands. Scots pine formed homogenous groups of regeneration and oaks were intermingled among other tree species. The height of the natural regeneration was moderately or highly differentiated in all stands. The overall structural diversity index showed that stand regeneration in the slightly or moderately disturbed stands was more differentiated than the young growth in the severely disturbed stands. The size differentiation of young growth is a long-lasting process and thus should be considered in practices aimed at the re-growing of areas after a natural disturbance. This process might be used to the replace monocultures with more diversified forests even in poor forest site types.

ABSTRAKTW pracy przedstawiono analizę smukłości 30-letniego niepielęgnowanego drzewostanu brzozy brodawkowatej (Betula pendula Roth.), rosnącego w warunkach siedliskowych boru mieszanego świeżego (BMśw). Materiał badawczy pochodził z trzech działek, będących częścią stałej powierzchni doświadczalnej Katedry Hodowli Lasu, założonej na terenie Leśnego Zakładu Doświadczalnego Siemianice. Badane brzozy brodawkowate charakteryzują się wysoką przeciętną smukłością wynoszącą, s = 1,31 [m/cm]. Stwierdzono, że smukłość jest skorelowania z niektórymi analizowanymi cechami biometrycznymi badanych drzew. Najsilniej związaną ze smukłością cechą jest pierśnica drzewa (d 1,3 ) oraz szerokość korony (d k ). Rosnące w niepielęgnowanym drzewostanie 30-letnie brzozy brodawkowate, ze względu na dużą smukłość są drzewami niestabilnymi, a przez to mogą być mniej odporne na szkodliwe działanie wiatru i śniegu.Słowa kluczowe: hodowla lasu, brzoza brodawkowata, smukłość, wysokość, pierśnica WSTĘP Korzeniewicz, R., Borzyszkowski, W., Szmyt, J., Kaźmierczak, K. (2016). Smukłość 30-letniego niepielęgnowanego drzewostanu brzozy brodawkowatej (Betula pendula Roth.). Acta Sci. Pol. Silv. Colendar. Ratio Ind. Lignar., 15(2), 79-86. DOI: 10.17306/J. AFW.2016.2.10 80 www.forestry.actapol.net/ Brzoza brodawkowata nie należy do gatunków, które wzbudzają duże zainteresowanie badaczy, aczkolwiek jest ważnym składnikiem polskich lasów. Jej udział powierzchniowy w strukturze gatunkowej wynosi około 4,4% (Wyniki…, 2014). Jest to gatunek pionierski, szybko rosnący, który ekologią i wymaganiami siedliskowymi nieco przypomina sosnę zwyczajną, jednakże woli gleby zasobniejsze i bardziej wilgotne (Jaworski, 1994;Jaworski, 2011). Potencjał brzozy brodawkowatej jest duży, wynikający bezpośred-nio z jej szybkiego wzrostu w młodości (Szymański, 1975;Szymański, 1982), wysokiej produktywności w różnych warunkach siedliskowych (Lockow, 1998) i zdolności adaptacyjnej, która pozwala jej pełnić główną rolę w regeneracji lasu (Ceitel i Iszkuło, 2000).Praca uzupełnia wiedzę dotyczącą kształtowania się wybranych cech biometrycznych brzozy brodawkowatej rosnącej w 30-letnim niepielęgnowanym drzewostanie. W pracy przedstawiono ocenę związku pomiędzy smukłością a innymi wybranymi cechami pomiarowymi drzew. Materiał badawczy zebrano ze powierzchni doświadczalnej Katedry Hodowli Lasu założonej przez Profesora Stanisława Szymańskiego. METODYKAPomiary i obserwacje wykonano na części powierzchni doświadczalnej (trzy działki z brzozą brodawkowatą), która została założona na terenie Leśnego Zakładu Doświadczalnego Siemianice, Leśnictwo Wielisła-wice, oddział 25h. Siedlisko jest borem mieszanym świeżym (BMśw), wykształconym na glebie bielicowo-rdzawej, porolnej, wytworzonej z polodowcowych piasków luźnych (Szymański, 1975;Szymański, 1982). Pod względem regionalizacji przyrodniczo--leśnej (Kliczkowska i Zielony, 2012) nadleśnictwo jest położone w Krainie Śląskiej (V), Mezoregionie Równiny Oleśnickiej (V.18). Zgodnie z regionalizacją geobotaniczną Matuszkiewicza (2008), teren na...