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Wyświetlanie 1-2 z 2
Tytuł:
Temporal variation in species composition, diversity and regeneration status along altitudinal gradient and slope: The case of Chilimo dry Afromontane forest in the Central Highlands of Ethiopia
Autorzy:
Tesfaye, Mehari A.
Gardi, Oliver
Blaser, Jűrgen
Powiązania:
https://bibliotekanauki.pl/articles/1046543.pdf
Data publikacji:
2019
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
Abundance
Ethiopia
altitude gradient
native species
population structure
saplings
seedlings and shrubs
Opis:
This study is aimed towards investigating the temporal variation in species composition, diversity and regeneration status of Chilimo dry Afromontane forest in the Central Highlands of Ethiopia. A total of 35 permanent sample plots of 20 m × 20 m (400 m2) each were established in the natural forest, laid out on transects of altitudinal gradients, with a distance of 100m between plots. The plots were measured twice in 2012 and 2017. Three subplots, 5m × 5m, and 1 m2 were laid out inside the main plots for sapling, shrub and seedling data collection. Species composition, diversity, important value index (IVI) and regeneration data were analyzed using appropriate formulas. Data analysis was made using R - studio software. A total of 31 trees and shrubs representing 25 families were recorded, 20 (64.52 %) were trees and 11 (35.48 %) were shrubs. Thereof, 28, 23 and 26 species under highest, middle and lowest altitudinal gradient were recorded. The most dominant tree species were: Juniperus procera, Podocarpus falcatus, Olea europea, Scolopia theifolia and Allophyllus abyssinicus. The species composition, diversity, abundance, dominance and important value index significantly varied among species, altitudinal gradient and slope. The diameter distribution was an inverted J - shaped distribution pattern. The highest species richness and diversity index were found under middle altitudinal gradient, while the lowest species richness and diversity index were found under the highest altitudinal gradient. The mean annual volume increment ranged from 4.223 to 0.228 m3 ha-1 yr-1, while the basal area increment varied from 0.85 to 0.020 m2 ha-1 yr-1. Among the sampled species, ten species had fair, 5 poor and 14 species had no regeneration. In conclusion, the Chilimo dry Afromontane forest is suffering from low recruitment and regeneration. Thus, appropriate forest management options should be implemented.
Źródło:
World Scientific News; 2019, 138, 2; 192-224
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The dynamics of the Taxus baccata L. population and the factors affecting its regeneration in the Jasień Nature Reserve
Autorzy:
Bujoczek, L.
Bujoczek, M.
Powiązania:
https://bibliotekanauki.pl/articles/2078292.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Instytut Dendrologii PAN
Tematy:
English yew
seedlings
saplings
diameter increment
diameter distribution
mortality
Opis:
Taxus baccata L. is a relict plant and has a scattered distribution in the entire species range. Yew regeneration may be affected by moisture conditions and tree stand characteristics – variables which change over time and which have not been sufficiently researched to date. The present study determined the size structure of yews, causes of yew mortality, the effects of tree stand characteristics and habitat conditions on yew diameter increment at breast height, the density of yew seedlings and saplings, and the likelihood of yew seedling occurrence. The study was conducted in central Poland, on 22 permanent sampling plots. The paper presents data col- lected in 2017 with reference to previous studies on these plots from 2001 and 2007. Stand volume, basal area, number of trees, canopy cover, and type of forest site were established for the tree layer. Saplings and shrubs were counted. Finally, the parameters determined for yew seedlings included density and percentage of individuals damaged by browsing, as well as soil moisture and percentage cover of herbaceous vegetation in the nearest neighborhood. In 2017, yew density in the tree layer was 70 individuals/ha, having increased by 15 individuals/ha over 16 years. During that period, 6.4 individuals/ha died in that layer. The predominant cause of yew mortality was wind. In the period 2007–2017, the mean diameter increment at breast height was 2.2 mm/year, and indicated a weak relationship only with tree diameter at the beginning of the studied period (R2 = 0.06). In 2017, the mean density of yew saplings and seedlings was 55 individuals/ha and 1005 individuals/ha, re- spectively. Two independent variables were found to be significant in the model of yew seedling occurrence: presence of mature yews on the sampling plot and soil moisture. The condition of the studied yew population is satisfactory, especially in the less moist areas. The number of seedlings is acceptable, but more active protection should be considered due to the scarcity of yew sap- lings. This is all the more important as seed-producing mature yews tend to die as a result of exposure to strong winds and periodic local flooding.
Źródło:
Dendrobiology; 2018, 80; 24-36
1641-1307
Pojawia się w:
Dendrobiology
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-2 z 2

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