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The aim of this paper was inventory of the wild service tree (Sorbus torminalis), a very precious but, at the same time, one of the least known species of homeland wooded plants in the Taczanów Forest Inspectorate (Poznań Regional State Forest Directorate). The inventory was conducted from May 2010 to March 2011. The result of the inventory are 1127 specimens, of which 209 are strong mature trees and 918 are seedlings and young trees in good health. The field research shows that the wild service tree grows in the Taczanów Forest alongside its central and eastern part in 22 Forest Compartments, 8 of which are in the Koryta Forest District and 14 are in the Taczanów Forest District. The average height of mature trees (d1.3 > 10 cm) was 18.02 meters and the average breast height  dimension was 26.22 centimetres. The dominant forest type in this area which is acid oak forest from Quercetea roboli-petraeae class creates optimal conditions for the growth of the wild service tree. This is proved by an analysis of the species population dynamics which is characteristic for the species biology. The study shows that earlier inventories conducted in this region are incomplete and out-of-date, and this present inventory substantially broadens the knowledge about the wild service tree in the Taczanów Forest in the context of its local and national population.
The paper presents the proposal of a strategy of conservation of genetic resources of wild service tree (Sorbus torminalis) in Polish forests. Some results of the recent studies on distribution, resources and genetic variability of wild service tree in Poland that make a scientific base of the programme are presented. Both in situ and ex situ methods should be applied in conservation of genetic resources of S. torminalis. Conservation affords should first to be focused on forest management oriented in favor of wild service tree (e.g. logging intervention, competition control, preparing of favorable sites for new establishments). Further, in situ measures should include selection of conservation areas (natural gene reserves) and preserving trees of the best quality (protected genotypes). These objects would provide seeds for new establishments and to feed populations of small size. The genotypes of the selected earlier preserving trees (about 250–300) would be protected in ex situ conservation objects – seedling and clonal seed orchards. These plantations would also provide seeds needed for future establishments. The genotypes of endangered populations or single trees of S. torminalis could be preserved in the Forest Gene Bank in Kostrzyca.
The subject of the study was a population of Sorbus torminalis resulting from spontaneous regeneration from seeds in northern Poland at the north-eastern limit of the species distribution. The population, occupying a fenced plot of 1.72 ha in the Forest District of Jamy, amounted to 579 individuals of variable age classes up to about 19 years old. Six polymorphic gene loci: MDH-B, ME-A, 6PGD-B, ADH-B, PGM-A, PGM-B were studied in 532 individuals recruited post-fencing and 21 potentially parental, adult trees. The analysis showed similarly high levels of genetic diversity within both subsets of individuals but there was also a noticeable change in genetic structure between them. Detailed genetic analysis of the post-fencing recruits revealed lack of significant differences between different age groups based on DBH within the fenced plot.
The available phytosociological data and original observations were used for preparing a list of plant communities with Sorbus torminalis on its natural sites in Poland. The community context of its sites showed a wide range: from pine-oak forests (alliance Dicrano-Pinion) and oak forests (Quercetalia robori-petraeae, Quercetalia pubescenti-petraeae) to oak-hornbeam forests (Carpinion) and beech forests (Fagion). Oak-hornbeam forests (Carpinion) are the most frequent communities with S. torminalis in Poland. Despite this, oak forests (especially the open thermophilous forests of Quercetalia pubescenti-petraeae) seem to be the most suitable sites for growth and reproduction of this light-demanding tree species. Some remarks on S. torminalis conservation in the community context were also presented as its passive protection in some forest reserves has proved to be ineffective or even harmful.
We performed a detailed overall field survey of all specimens of the wild service tree Sorbus torminalis (L.) Crantz in the research area in the Hádecká planinka National Nature Reserve. This research area, with an area of 80 ha, contains one of the largest populations of the tree in Europe. In all, 1713 specimens were found. This study provides a detailed description of the wild service tree population in the area. The basic biometric parameters (height, GBH, social position, fertility) of thepopulation were assessed. The main emphasis of our analysis was to evaluate the population's age structure. We used estimates of age structure based on the Chapman-Richards growth function to perform this evaluation. During the past twenty years, the natural regeneration of the wild service tree in the nature reserve has decreased considerably. At an experimental plot where a high forest was converted to a coppice with standards, regeneration occurred over 75% of the area. Root suckers were found at the beginning of the observation period. After 2–3 years, generative regeneration occurred.
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