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1
Artykuł dostępny w postaci pełnego tekstu - kliknij by otworzyć plik
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Influence of initial light intensity and deer browsing on Taxus baccata saplings: a six years field study

100%
Iszkulo G., Nowak-Dyjeta K., Sekiewicz M.
Dendrobiology
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2014
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tom 71
European yew (Taxus baccata L.) is a rare species, but is the focus of great interest because of the species recovery attempts and its use in medicine. The aim of this study was to determine the optimum conditions for the development of the young generation of this species. Four-year old yew seedlings were grown under artificial light reduction: 2, 8, and 30%, as well as in full light. The seedlings were then planted in natural conditions in fenced and unfenced areas. The results of six years field studies indicated that the greatest impact on survival was shown by the light conditions from the period before planting under the canopy of trees. Seedlings from the 2 and 8% of light showed the greatest mortality. The reason was the sudden change in light conditions, because at the time of planting (early spring), there was no reduction of light under deciduous trees. Almost all of the unfenced yew seedlings were grazed by deer, but yew survival in the unfenced group was surprisingly high despite the permanent grazing. This was explained by the high resistance of yew to cutting and the protection of seedlings by a dense layer of Rubus. The results indicated that yew trees require protection against animals for normal development, even if animals have not previously had contact with Taxus and that yew seedlings are very sensitive to sudden changes in light. Both conclusions can be applied in the development of natural and artificial regeneration of European yew and other endangered plants.
2
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Ecology and conservation status of Taxus baccata population in NE Chalkidiki, northern Greece

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Katsavou I., Ganatsas P.
Dendrobiology
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2012
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tom 68
Taxus baccata L. is a rare species threatenedwith extinction in Greece, as in other parts of Europe. This paper deals with the ecological status of the species in the area of NE Chalkidiki northern Greece, where the species appears in one of the greatest populations of the country. Site, standand yew population characteristics were studied in the area that species occupies. Eleven sample plots were marked, and on each plot, the height and diameter at breast height (DBH) were measured for all yew trees, as well as for all the individuals of the rest tree species, with diameter at breast height greater than 4 cm. Tree vitality of all trees was also estimated according to IUFRO classification. Yew radial growth was studied using tree-ring analysis. Tree natural regeneration was investigated within subplots of different dimensions and according to two height classes. Results showed that yew population occurs in stands dominated by beech, presenting a mean density of 301 trees per hectare, with a total population of 430 trees with DBH above 4 cm. It forms the secondary stand, and dominates in the stand understorey, accompanied with Fagus sylvatica and Ilex aquifolium, while it appears rarely in the overstorey. Yew tree vitality was foundto be quite high, and significantly higher than that of beech. Radial growth of the sampled trees follows a slow and constant annual increment gradually decreasing by tree age. Yew natural regeneration was foundto be relatively low, 1341.8 individuals (seedlings and saplings up to 1 m) per hectare. Management and in situ conservation of the species in the area should focus on species protection measures, andon specific silvicultural treatments for creating favourable conditions for species growth.
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The influence of stand structure on European yew Taxus baccata populations in its natural habitats in Central Poland

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Dobrowolska D., Niemczyk M., Olszowska G.
Polish Journal of Ecology
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2017
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tom 65
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nr 3
Taxus baccata is a rare species throughout its entire natural range and is often categorized as nationally threatened in countries where it occurs. In Poland yew is under protection and almost all sites with yew occurrences are subject to reserve protection. The aim of the study was to answer the following questions: What is the tree diameter structure of stands in three yew reserves? What is the stand biodiversity of three yew reserves in central Poland? How does the stand species composition influence natural regeneration of yew? What shall be done in the future to protect yew in its natural habitats? The study was conducted in three yew reserves in central Poland. Based on a detailed research on 30 circular sample plots established in each reserve we found high stand diversity in all investigated areas. Shannon-Weiner index (H´) was high in general and ranged from 1.50 to 1.69, and the Shannon's index of evenness (E) ranged from 0.51 to 0.64. The diameter structure of two studied reserves was similar to natural multi-layered stand structure. The number of yew trees and their vitality was low. The species diversity of natural regeneration in all reserves was very high. However, the quantity and quality of yew regeneration in multi-layered diameter structure was significantly lower than in one-layered stand structure. To protect yew, appropriate conservation measures should be undertaken, including silvicultural treatments for in situ species conservation. We found that passive conservation is an inappropriate strategy for yew because of its weak competitiveness ability. We recommend active conservation approach, including silvicultural treatments. i.e. cutting broadleaved trees in places where the basal area is the highest, removing some trees in the upper layer of stand which compete with yews. Individual protection of yew seedlings and saplings is also necessary because of damages caused by herbivores.
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Light limitation of growth in 10-year-old seedlings of Taxus baccata L. [European yew]

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Iszkulo G., Lewandowski A., Jasinska A. K., Dering M.
Polish Journal of Ecology
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2007
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tom 55
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nr 4
Taxus baccata L. is a rare and endangered species with restricted occurrence. One or two-year-old yew seedlings occur quite frequently in natural stands of the species, but older seedlings are rarely observed. Therefore we investigated the relationship between light intensity and the growth rate of ten-year-old seedlings of the European yew Taxus baccata (L.). The study was conducted in a preservation area established in 1999 in order to protect the gene pool of the ‘Cisy Staropolskie’ Reserve in the Bory Tucholskie Forest (northern Poland). A total of 570 three-year-old seedlings were planted under the canopy of a 45-year-old forest stand composed of oak (50%), birch (40%) and hornbeam (10%). Measurements of seedling heights were taken in 1999, 2003 and 2005. In 2005, the current annual growth increment was measured. Relative Photosynthetic Photon Flux Density (RPPFD) up to 30% had a positive influence on the height and annual height increment of the yews, but most of individuals grew below 5% RPPFD. This suggests that increasing light level would increase growth of yew in both natural recruitment and planting.
5
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Dendroecological differences between Taxus baccata males and females in comparison with monoecious Abies alba

80%
Iszkulo G., Jasinska A. K., Sobierajska K.
Dendrobiology
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2011
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tom 65
Taxus baccata L. is a rare and endangered dioecious species in Europe. Species of this mating system are considered to be the most vulnerable to extinction. It is believed that one reason for this state may be the uneven reproductive effort and different habitat requirements of the two sexes. Silver fir and European yew have very similar ecological requirements, but fir is a monoecious species. The aim of this study was to compare the growth rate andthe effect of precipitation andtemperature on the annual tree-ring width of silver fir and both sexes of European yew. The study site was the Knyazhdvir reserve in western Ukraine, located near the limit of the geographical range of both species. Knyazhdvir reserve is the site of one of the last yew populations in Europe with a large number of individuals (about 15,000 individuals above 1.3 m height) growing alongside fir.Woodsamples were taken from 15 male and15 female specimens of T. baccata andfrom 15 specimens of A. alba and were subjected to a standard dendrochronological procedure. The results showed high positive correlation between the temperatures in February andMarch andthe tree-ring width in the studied species and genders. The response of annual tree-ring width to the examined climatic factors was relatively similar in yew andfir. However slight differences were foundbetween males andfemales of T. baccata. The growth rate decreased more rapidly in females compared to males, probably following sexual maturation. Precipitation in April hada positive effect on firs andfemale yews, but not on male yews. This confirms earlier reports of the requirement of female specimens of dioecious species for a higher humidity than male individuals.
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Success and failure of endangered tree species: low temperatures and low light availability affect survival and growth of European yew (Taxus baccata L.) seedlings

80%
Iszkulo G.
Polish Journal of Ecology
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2010
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tom 58
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nr 2
European yew (Taxus baccata) is a rare and endangered species in many European countries. Observations of high levels of T. baccata seedling mortality under the canopy of mature trees suggest that mortality due to low irradiance may contribute to the decreasing population size of this species. The primary goal of my work was to determine if light and nitrogen fertilization influence the growth and survival of T. baccata seedlings. In 2002 and 2003, we carried out a field experiment with a range of light availabilities (reducing artificial light and obtained 2, 8, 30 and 100% RPPFD -Relative Photosynthetic Photon Flux Density) and a nitrogen fertilization treatment (with and without NH₄NO₃ fertilizer). In 2002 and 2003, the mortality of one-yearold seedlings was very high after the first winter, especially within extreme light conditions (2 and 100% RPPFD). Biomass of seedlings was highest in 30%, intermediate in 100% and lowest in 8% and 2% RPPFD. High levels of seedling mortality during the winter suggest that low temperatures were the primary determinant of T. baccata seedling survival. Nitrogen fertilization only had a positive effect on growth in higher RPPFD values (8, 30 and 100%). Both total needle mass and needle mass allocation were higher in the nitrogen fertilization treatment Interaction of low temperature and light availability is probably the direct reason of high mortality of T. baccata seedlings located near the species range limit.
7

Interaction between canopy tree species and European yew Taxus baccata [Taxaceae]

80%
Iszkulo G., Boratynski A.
Polish Journal of Ecology
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2004
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tom 52
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nr 4
The aim of the study was an examination of the thesis, that canopy tree genera (species) can have positive or negative influence on the germination of seeds and growth of seedlings and saplings of Taxus baccata. The species population spontaneously formed in the Kórnik Arboretum (W Poland) during last decades was the field of investigations. All yew individuals (including seedlings) were positioned and measured on two plots (area 1900 and 2000 m²) permanently marked in the field. The crown ranges of canopy trees and tree-like yews were measured and projected on the maps. The numbers of seedlings, saplings and tree-like yews under canopies of particular tree genera were compared. The seeds of T. baccata germinated under canopies of all species, most abundantly under the canopy of Pseudotsuga and Abies, but also under mother trees. Seedlings older than 2 years were also most numerous under the canopy of coniferous trees, while the saplings under the canopy of broadleaved trees. The greatest numbers of tree-like individuals were found under Tilia and Carpinus species.
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