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Japanese larch (Larix kaempferi Sarg.) is one of the most frequent exotic species in Polish woodlands. The basic object of research comprised 60 stands of the studied species, located mainly in the northern and western parts of Poland. The growth results for the studied species, evaluated on the basis of the average height (hg55), were compared with data describing the local climate and the stand location within the botanical and climatic zoning. The results confirm the opinion that the Japanese larch prefers a climate of maritime character and generally shows high degree of flexibility regarding its climatic requirements (very large differences between the growth conditions in the studied area and the country of origin). The dependence between the growth results and precipitation is however lower than expected. The most interesting results include the relatively clear connection between the height of the larch stands and the Degórski’s (1984) ‘floristic’ ‘K’ (continentality) index.
Heterobasidion annosum (Fr.) Bref. is a fungal pathogen causing root rot – one of the most economically important diseases in coniferous stands in Europe, Asia and North America. A major objective of this study was to determine if the offspring of self-sown trees from natural regeneration in old foci of root rot is more resistant to infection by this pathogen than the offspring of plus trees. In experiments conducted in the greenhouse above 700 seedlings grown from seeds collected from 60 trees in 6 old foci of the disease (research plots) and 480 seedlings grown from seeds collected in 4 seed orchards were used. The pathogen was represented by 7 different fungal strains. Plus trees, whose grafts are used to establish seed orchards, were the selected elite of forest trees, but their offspring after inoculation with H. annosum had significantly worse results than the seedlings developed from the seeds collected in old foci of the disease (research plots). The greatest differences were observed in seedling dry weight. In inoculated seedlings from seed orchards it was 14% lower than in the control, while the dry weight of inoculated seedlings from research plots did not differ significantly from that of non-inoculated seedlings.
Until recently, the level of industrial air pollution in the Sudetes (a mountain range extending on the Czech Republic and Poland border) was very high.This caused a large-scale forest decline, especially in the western part of the Polish Sudetes: in the Izerskie and Karkonosze Mts. An analysis of data on fir defoliation in that area, collected directly after the period of heavy industrial pollution, showed a clear dependence of the degree of defoliation of the primary crown on canopy density: the lower the density, the higher the degree of defoliation.
Interactions between 42 higher fungi and six strains of Heterobasidion annosum (Fr.) Bref., representing P and S intersterility groups were studied in vitro. Part of the higher fungi was represented by strains of ectomycorrhizal fungi indigenous to old disease centres caused by H. annosum in pine stands. Variation in antagonism to the pathogen was observed both within and between the species. The antagonism was dependent on growth rates of fungi in control. Fungi growing faster displayed a greater ability to arrest the development of the pathogen mycelia. The same tendency was observed in the strains of H. annosum, which generally grew faster and their growth was restricted less than that of higher fungi. Two strains of an ectedomycorrhizal fungus Mrg X, accompanied by a helper bacteria reduced mycelial extension of H. annosum by 72% and 76%. Among ectomycorrhizal fungi, the most effective antagonists were strains of Xerocomus subtomentosus, Amanita muscaria, A. citrina and Laccaria laccata. Three various types of interaction between the studied fungi were observed. Inhibition zone between interacting mycelia appeared often, however the fungi displayed this antagonistic property not to all strains of the pathogen. Although mycelia of H. annosum invaded colonies of the other fungi frequently, in none of the treatments growth of the higher fungus over the opposing colony of the pathogen was observed.
On the basis of historical and recent cadastral maps, topographic maps, and aerial photographs, we analysed changes in forest area within the cadastral units of Karpniki village, in the Karpnicki Potok (SW Poland). In 1823−2012, forest area increased there from about 41% to over 57% of the total area. The greatest increase has been recorded recently. Moreover, at that time over 16% of land classified officially as farmland was naturally colonized by communities dominated by woody plants. This seminatural process in the analysed case does not pose any serious threat to natural resources, but a complete lack of its control may lead to deterioration of the value of the local landscape and development of low−quality forest stands. The observed changes seem to be typical of other areas located in lower parts of the Sudety Mountains.
Elm resources in Poland were analysed on the basis of latest forestry inventory data (updated in 2012). As compared with the 1970s, a remarkable increase was noticed in the total area of forest stands dominated by elms. However, the contribution of elms to the total forest area in Poland is still small (17 653.67 ha, i.e. 0.24% of the total forest area), while forest stands dominated by them cover only 1011.84 hectares (0.01%). Elm forests are the most frequent at alluvial sites, but majority of elm trees is scattered in lowlands, mostly at the fertile potential sites of oak−hornbeam forest. Elms do not prefer any part of Poland, but their contribution is markedly lower in forests of the Sudety Mountains.
Three elm species are native to Poland: wych elm (Scots elm) (Ulmus glabra Huds.), field elm (U. minor Mill.), and European white elm (fluttering elm) (U. laevis Pall.). The epidemic of Dutch elm disease (DED) has led to a decrease in the popularity of elm cultivation. An analysis of forestry data was the first step in the assessment of elm resources. The area of forest stands where elms are dominant has more than doubled since 1978. Lowland alluvial forests rank first in regards to the number of elm localities per unit area of a given forest site type. While this site type is clearly preferred by elms, the majority of elm trees are actually scattered among sites of oak-hornbeam or closely related forests (of the alliance Carpinion betuli). Field research revealed a clear dominance of U. laevis, a species which in the past was predominantly located out of woodland and rarely cultivated. Data analysis indicated that all trees greater than 70 cm in diameter belonged to this species. Data from plots surveyed directly also suggest that the three elm species have slightly different habitat preferences. U. laevis prefers riparian habitats, although the major part of its resources is now on potential sites of oak-hornbeam or closely related forests. U. minor even more often than U. laevis occurs at less humid sites (mostly potential sites of oak-hornbeam or closely related forests), while U. glabra prefers moist slopes. In general, it appears that the impact of DED in the last 20–30 years has been smaller than in the preceding period, however, the disappearance of the disease has not been established. Undoubtedly, U. laevis is the elm species that is least impacted by DED
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Dutch elm disease (DED) still occurs in Poland. Previous studies confirmed occurring O. ulmi and two subspecies of O. novo-ulmi: subsp. novo-ulmi and subsp. amerciana. In this study the population of Ophiostoma occurred in Poland was investigated. The disease incidence was investigated on elms growing in 39 locations. The pathogen’s mycelium was isolated from elm branches and twigs collected from 22 plots. The disease symptoms were noted in 5% to 35% trees. Fungi were identified based on the PCR amplification of the ITS 1/2 rDNA together with phylogenetic analysis of this region. Ophiostoma novo-ulmi was the only agent caused DED on Ulmus glabra, U. minor and U. laevis. There were no genetic diversity of O. novo-ulmi Polish population in analyzed ITS region. All kind of specific symptoms and disease intensity occurred independently on elm species and host age. Ulmus minor was infested most sever among the three elms species.
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