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Addis Ababa University Libraries Electronic Thesis and Dissertations: AAU-ETD! >
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Thesis - Environmental Sciences >
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http://hdl.handle.net/123456789/3337
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| Title: | Assessment on the Recent Drying-Up of Eucalyptus Species in Selected Areas of the Highland of Arsi and Wollo, Ethiopia |
| Authors: | Demelash, Bekele |
| Advisors: | Mekuria Argaw(Dr.) |
| Keywords: | Arsi
Wollo |
| Copyright: | Oct-2010 |
| Date Added: | 12-Jul-2012 |
| Publisher: | Addis Ababa University |
| Abstract: | Drying-up of Eucalyptus species is not a common phenomenan in Ethiopia. The objective of
this study was to assess the possible causes of the drying-up of the trees of major
Eucalyptus plantations in two selected case areas and to make a recommendation for
remedial measures. Systematic sampling was employed and 20m×20m quadrats at 100m
interval were laid out along transect. In each quadrat vegetation and soil were assessed for
biotic & abiotic factors. Among the abiotic factors soil depth, soil texture, bulk density, water
holding capacity of the soil, slope, and aspect were assessed. Among the biotic factors soil
and root pathology and stand density were assessed. Pearson correlation coefficient was
used to compare the strength of the relationship of the parameters with mortality rate of the
trees. ANOVA was also used to compare rooting depth of the live and dried trees. Mortality
rate of Eucalyptus camaldulensis is negatively correlated with soil depth with a correlation
coefficient ( pearson coeff.= -0.8507, P=0.0157) and (Pearson coeff.=-0.9393, P=0.0175) for
both case area I and case area II, respectively. There were no correlation between all other
soil physical factors and mortality. The rainfall was very much below the average or
complete failure of rain (i.e., 0 mm in the months of February & March and 18.1mm in April
of 2008) and the temprature went above the average, i.e, 270c for 6 consecutive months.
According to litreature such climatic pattern resulted in drying-up in the following year. Root
and soil samples test for phytophtora, which is known to cause root rot were assessed and
found negative for both the healthy and dried sample trees. On the other hand a comparative
disease symptom assessment of the stems of the live and dried trees were made and the
result showed that there was no indication of disease. Among the parameters taken only soil
depth found to be the likely cause of Eucalyptus drying-up. All the other possible causes
assessed didnt correlated significantly. As the result indicated from this study, it can be
concluded that shallow soil depth through its effect on moisture availability resulted in
Eucalyptus dry-up in the long term. |
| Description: | A thesis submitted to the partial fulfilment of the Msc. degree
in Environmental Science |
| URI: | http://hdl.handle.net/123456789/3337 |
| Appears in: | Thesis - Environmental Sciences
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