Parkland agroforestry woody species are prominent features in many landscapes worldwide, and their ecological, social and economic importance is widely acknowledged. It is the traditional agroforestry systems from different countries and is almost a universal occurrence in Ethiopia. This study was conducted in Gindeberet District, West Shoa Zone, Oromia Regional State, Ethiopia to assess the parkland agroforestry woody species composition, diversity, structure and biomass carbon. Woody species inventory was carried out on 103 plots (each, 50 m x10 0m) in the crop field laid along 7 transects. For woody species ≥ 5 cm DBH, measurements of DBH and tree height were taken. A total of 61 woody species belonging to 35 families were recorded. The study indicated that the woody species Shannon and Simpson diversity indices were higher at lowland than midland agro-ecology. The species richness was significantly different between the two agro-ecological zones (X 2 = 8.5, p = 0.003). This study showed low carbon storage potential in living biomass of woody species; it is recommended to develop a policy on the woody species management, conservation and regeneration to increase the carbon storage potential in living biomass of woody species.

<p><strong>Background</strong>. Altitude affects growth and distribution of plants and influences the impacts of other environmental factors on plant growth and development. <strong>Objective</strong>. The objective of this study was to investigate the effect of altitude on the growth performance and carbon sequestration potential of <em>Moringa stenopetala</em> in the Konso Zone, Southern Ethiopia. <strong>Methodology</strong>. The three sites that were selected for the study include Bayde (1300-1500 masl), Gamole (1501-1700 masl) and Fasha (1701-1900 masl). From each site three age classes (6-10 years, 11-15 years and 16-20 years) were selected for the study. Six farmers were selected from each location and three trees from each farmer’s land under each age class were selected for measuring height and diameter. Non-destructive method was used for estimation of biomass and carbon contents of different age groups. <strong>Results.</strong> The results indicate that growth performance (height, diameter, volume, biomass production) and carbon sequestration of <em>M. stenopetala</em> was significantly higher (p &lt; 0.05) at lower altitude as compared to mid and high altitude. It was concluded that <em>M. stenopetala</em> tree within 6-10 age class can sequester 10.96 kg of carbon stock by capturing 40.17 kg of carbon dioxide, while for age class of 11-15 the value of carbon storage and carbon dioxidesequestered is27.87 kg and 102.20 kg respectively. Similarly maximum sequestration of carbon dioxide was recorded (42.31 Kg and 155.11 Kg respectively) for 16-20 age class. _.The annual sequestration of carbon was found maximum for class 16-20 (8.62 kg) followed by 11-15 class (7.86 kg) and lowest for 6-10 class (5.02 kg). <strong>Implications</strong>. The findings of present study will be helpful in knowing the effect of age and altitudinal variation on carbon sequestration potential of <em>M. stenopetala.</em> <strong>Conclusions</strong>. It is concluded that carbon sequestration potential of Moringa decreases with altitude and increases with stand age.</p>

<p><strong>Background.</strong> There is a need to understand multipurpose trees promotory or inhibitory allelopathic effects prior to selection of any crop to be cultivated in their vicinity. <strong>Objective.</strong> Present study was carried out during 2019 on Arba Minch University Research Farm with the specific objectives of to investigate the effect of leaf extract of some multipurpose trees and its concentrations on growth and production of Maize. <strong>Methodology.</strong> Leaf extracts of 3 species namely <em>Moringa stenopetala, Croton macrostachyus</em> and <em>Terminalia brownii</em> were tested at 5 concentration levels (0%, 25%, 50%, 75% and 100%). The experiment was laid out with Randomized Complete Block Design with three replications. The leaf extract was applied at biweekly interval right from its emergence. <strong>Results. </strong>The growth components which were significantly affected by the application of leaf extracts include leaf length, leaf area, stem thickness and days to tasseling of maize while effect of leaf extract on plant height, number of leaves plants^-1, days to silking and days to maturity was found non significant. On the other hand with the exception of number of cobs plant^-1 all yield and yield components, like number of grains row^-1, number of grains column^-1, number of grains cobs^-1, 1000-seed weight of cob, length of cob, diameter of cob, fresh and dry yield of maize were significantly varied with leaf extracts of the selected MPTs and their concentration levels. The application of leaf extract resulted in increase in yield from 6.95 T ha^-1 (control) to 8.95 T ha^-1, 7.58 T ha^-1 and 7.40 T ha^-1 for <em>Croton macrostachyus</em>, <em>Moringa stenopetala</em> and <em>Terminalia brownii</em> respectively. <strong>Implications. </strong>The results of the present study contribute in knowing the positive or negative effect of leaf extract of three MPTs on Maize production.<strong> Conclusions. </strong>It can be concluded that introduction of these multipurpose trees in farmland under agroforestry system is safe and without any inhibitory allelopathy. Thus leaf extract application of these species are recommended for further improvement of maize yield. </p>