This review was made to bring forth the contradicting outlooks from different research findings, challenges on the Eucalyptus species and show the opportunities we have with the tree. Due to the impact of Eucalyptus tree species on ecological health and agricultural productivity, ecologists, policy makers and politicians have had a negative view on this tree species. Hence, attempts are made to remove the tree from the agricultural landscape in some part of Ethiopia. In contrast, the farmers of Ethiopia prefer the fast growing, economically attractive, and the quality wood yields of Eucalyptus tree species. So we need to look for other dimension to coincide the existing contradictions. Eradication of the tree cannot be solution without replacing with suitable tree species for maintaining biodiversity and ecological balance. The tree can continue to supply fuel wood and construction material and thereby retard the rate of deforestation and loss of biodiversity resources of the remnant forests of the country. Collaborative work is crucial to gear efforts towards the establishment of a proper management system for the cultivation of Eucalyptus tree. Appropriate management practices such as species selection, planting site selection, correct site-species matching and efficient utilization can maximize the opportunity obtained from the tree. It is also very important to look for alternative trees species to replace Eucalyptus trees, and further studies are required to test the level of Eucalyptus species impact on specific ecosystem. Also, polices need to achieve a reasonable trade-off between the socioeconomic value and agro-ecological conservation.

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This study aims to compare the proportion of macronutrients in different parts of the aboveground biomass; and to estimate the amount of macronutrient loss from continuous farmlands (mechanized farm and traditional farm) and plantation stands (Cupresus lusitanica and Eucalyptus saligna) through harvesting. From 20 × 20 m 2 sized sample plots, a representative samples were collected from leaf, branch and stem of the plantation stands. Macronutrient analyses were carried out for the samples taken from plantations and maize crops on continuous farmlands. All data collected were subjected to ANOVA using the general linear model of SAS 9.0 at P < 0.05. The results of macronutrient in aboveground biomass of maize in the continuous farm lands shows that, the grain component contained as much as 50% of N and 60% of P compared to leaf and stem. However, a high proportion of K, Ca, and Mg were found in the leaf and stem components. In the case of C. lusitanica, 64.4% N, 70% P, 68.4% K, 65.3% Ca, and 68.75% of Mg was found in the stem compared to the leaf and branch. In the E. saligna, the stem contained 22% N, 30% P, 11.8% K, 26.6% Ca, and 12.5% Mg; with the remaining proportion of each nutrient found in the leaf and branch. Based on the results, much of the nutrients can be removed through the leaf and stem removal in the continuous farmlands. Complete removal of the biomass with little residue returned to the soil, for long periods under plantation land use, may also lead to macronutrient depletion. Therefore, to minimize this effect, the aboveground biomass harvest should focus on grain only on the farmlands, and stem only on the plantations. 57

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