Abstract:The genetic variability and biodiversity of tree populations ensure the stability and sustainability of forest ecosystems. New research tools based on molecular DNA markers enable precise characterisation of forest genetic resources, i.e. detection of different allele frequencies in mature trees and progeny populations. The paper describes the genetic structure of mature stands of Scots pine (Pinus sylvestris L.) in Oława Forest District and Norway spruce (Picea abies L. Karst.) in Jawor Forest District and stands of their respective progeny.In the Scots pine stand, there was a slight increase (0.6%) in heterozygosity level and a larger increase (4.9%) in the inbreeding coefficient of progeny trees. In the Norway spruce stand, despite a small reduction (0.9%) in heterozygosity, a similar increase (4.6%) in the inbreeding coefficient of progeny was revealed. In both stands, allele richness and the partition probability of basic clustering were high. Both pine and spruce adults and progeny trees were characterised by high levels of genetic similarity (96% and 79%, respectively). Gene flow between the mature and progeny populations was high (N m > 1) for both Scots pine and Norway spruce.Conservation of the gene pool within forest tree stands requires an increase in the proportion of natural regeneration. To estimate the extent to which genes are transmitted between adult trees and their progeny, more studies are needed, especially taking into account the influence of silviculture measures, like selective tree cutting, on the genetic variability of the younger generation.These results confirm that the gene pool was conserved when transmitted between the stands studied, as well as highlight the usefulness of such a study for silvicultural purposes.

Illegal logging is a major problem in many European countries. Recent progress in molecular biology, however, has significantly improved the ability to accurately identify wood material. In this paper, the first application of microsatellite DNA markers is described in a case of illegal logging of European ash wood in Polish State Forests. The genetic fingerprints of seized ash wood samples were determined using six nuclear and four chloroplast microsatellite loci, characterized by sufficient stringency in forensic analyses. By comparing the DNA profiles obtained, the origin of one sample of ash wood used as evidence material was confirmed, from among three samples serving as reference material with 99.99999% of probability. This work demonstrates how DNA authenticity testing can serve as an important technical tool in monitoring the legality of the suspected ash timber and confirms the utility of these techniques in detecting illegally logged timber in general.

Precise identification of biological samples remains the most important proof in the forensic science. Illegal logging has become the urgent issue in Poland during the last decades, and conventional methods of investigation turn out to be often insufficient. Recently, the DNA-based markers (SSR and cytoplasmic genes) can remarkably help in the forensic botany performed by the Forest Service Guards and the Police investigation in illegal logging of timber. The identification method relies on comparison of the piece of evidence (i.e., stolen wood fragments) with the piece of reference (e.g., tree parts remained in the forest). We present the usefulness of the DNA neutral markers (i.e., microsatellite loci) and cytoplasmic genes in forensic botany based on several case studies of illegal wood identification in Poland, concerning the most economically important coniferous tree species such as Pinus sylvestris L., Picea abies (L.) Karst., Abies alba Mill., and Larix decidua (L.). Thanks to the DNA profiles established on the basis of minimum 4 microsatellite nuclear DNA loci, and at least one cytoplasmic organelle (mitochondrial or chloroplast) DNA marker, the determination of the DNA profiles provided fast and reliable comparison between material of evidence (also wood and needles) and material of reference (first of all tree stumps) in the forest. These data strongly supported the decision taken by several District Courts in Poland, as far as the

The work detailed here in the context of the above project sought to determine changes in the gene pool (at the DNA level) in a stand of Scots pine (Pinus sylvestris L.), under the influence of various kinds of forest-tending cuts. The experimental area on which the research was focused is located in Poland’s Ostrów Mazowiecka Forest District. Genetic structure was specified using five nuclear SSR sequences and six chloroplast SSR loci, while the five thinning variants trialled were sanitation cutting, low thinning of 30% intensity, schematic thinning, selective thinning and destructive lumbering. The control variant was left untreated. It was virtual rather than real-life thinning that was pursued, using the ForestSimulator BWINPro program. Changes in the structure of the stand after a further 10 years were also simulated. The different thinning variants were shown to cause change in the gene pool and level of genetic diversity of trees in the study area. In terms of maintaining genetic variability in the stand, the least-favourable method proved to be thinning from below. Destructive selection cutting was in turn most beneficial in terms of the preservation of genetic structure, with the reduction in rare alleles being more limited than in any other analysed variant. It was with the selective thinning variant that the final number of trees, stand structure and level of genetic variation resembled the situation in the control most closely. This suggests that selective thinning provides for a rather accurate replication of processes occurring in nature.

The paper describes a number of molecular methods used in the past and now to analyze forest tree species. Taking into account the economic importance of forest trees and in view of the timber economy, wood properties and characteristics are essential factors subjected to control, observation and research. Molecular techniques that support traditional selection methods allow for genetic diversity analyses considering a range of research aspects. The development of these techniques at the turn of the last two decades has enabled wide-ranging use of molecular data in studies on forest tree populations. On the example of pine (Pinus L.), the paper presents data based on molecular studies as well as a variety of possibilities to apply the obtained results.

Scots pine (Pinus silvestris), is one of the dominant species in Poland and one of the main forest tree species in northern and central Europe. This species is of great economic importance. The Scots pine is highly adaptable to changing environmental conditions. A number of ecotypes have been characterized and the formation of these ecotypes are related with development of different phenotypic characteristics; morphological, physiological, and ecological. Molecular studies, based on DNA polymorphism, have been used for more than 20 years to analyze the genetic diversity of the Scots pine population. The most popular are microsatellite markers due to the fact of wide availability and high polymorphism. However, the use of these markers is also associated with certain limitations, due to complex mutation models or high incidence of homoplasia. These features are prompting scientists to look for alternative types of markers such as, for example, SNP. In our study we conducted a comparison of the basic parameters of genetic variability of two Scots pine stands (25 and 24 trees in each) for 20 SNP markers and 4 microsatellite markers. For the 20 SNP loci the observed heterozygosity (Ho) was equal to 0.34 for both stands and the expected heterozygosity (He) was equal to 0.34 for the first stand and 0.37 for the second. No statistically significant genetic distance was observed between them. For the microsatellite markers observed heterozygosity (Ho) was 0.81 and 0.74, and the expected heterozygosity (He) was equal to 0.85 and 0.85 respectively for the stands, and similarly no statistical significant genetic distance was observed. Literature data of different genetic markers showed the higher informativeness of randomly chosen microsatellites than single nucleotide polymorphism (SNP) markers for study population differentiation. But some analyzes confirm that the appropriate number of SNP markers can be more informative for population structure inference.

The unpredictable nature of climate change impacts, e.g. warming producing a latitudinal shift in photoperiod, may modify trees’ rates of survival and capacities for growth. This is also true of the Scots pine (Pinus sylvestris L.), as one of Europe’s main forest-forming tree species. The best results in the study of tree responses to climate change can be obtained during long-term experiments carried out on provenance trials. Such objects make it possible to precisely determine the growth and adaptation reactions of offspring coming from different soil and climatic conditions to the conditions of the research area. Research of this kind has been conducted by analysing growth in the progeny of 16 different Polish provenances of Scots pine on a single provenance experiment located in the centre of Poland, in an area where annual precipitation is at the rather low average level of 580 mm. The experiment was established in 1966, using a randomised block design with five replicates for each of the tested provenances. In autumn 2015, trees present were monitored and analysis of variance was used for their heights and diameters at breast height, with estimates also made regarding straightness of the trunk, crown width and branching angle. At the same time, ecophysiographic features of the places of occurrence of parent stands for each of the provenances were also analysed, with a quantification of the relationship between the growth traits studied and ecophysiographic features also achieved using PCA, while Ward’s Method of clustering was used to establish provenance groups characterised by multi-trait similarity. In the light of what is known about forecast climate change, it would be possible to transfer progeny of different pine populations, if only from places where levels of precipitation are lower, along with values for the De Martonne aridity index. In practice, Central Poland might play host to the progenies of pines from the western part of the country—as represented here by the Bolewice, Rychtal, Karsko and Gubin provenances. On the other hand, the progenies of pines from stands at higher altitudes will not be suitable for cultivation in lowland locations in Central Poland.

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