The research aimed at improving the management of this system silvopastoril in high altitude areas, was conducted in the Central Experimental Botany, University of Nariño, located at 1 ° 09'28 .3''N, 77°16'29.5"O. The objective was to measure the efect of Acacia decurrens on some of the grass Aubade Lolium multiflorum Lam height of plants, green fodder, leaf: stem and percentage of dry matter. Differences were statistically significant (p <0.01) for all variables analyzed. Grass Aubade Lolium multiflorum Lam planted at distances of 0 at 0.5 and at 0.5 to 1 m above the highest values offered Acacia decurrens plant height (AP) and green fodder (FV) with values of 58.7 and 50.7 cm and 60.8 and 53.5 ton/ha, percentage of dry grass (%MS) ranged between 9.06 and 4.97 when it was planted of 1.5 at 2 and 0.5 at 1 m, was greater leaf: stem (RH:T) grass planted at 0 m under the influence of the tree with a value of 4.20. There was a positive trend between % MS and the RH: T and the negative % MS to the production of FV and AP. Keywords: grass, tree, green fodder, dry matter, leaf: stem