Abstract

CARRANZA, Carlos A.; PIETRARELLI, L.; LEDESMA, M.  and  BALZARINI, M.. Growth of Prosopis flexuosa D.C. in the Chaco Arido Argentino, after the elimination of the shrub layer. Multequina [online]. 2000, vol.9, n.1, pp.119-133. ISSN 1852-7329.

Large areas of the Chaco Arido Argentino are presently covered by a shrubby steppe of low economic yielding owing to its prolonged history of felling and grazing. As a way to increase the production of fodder in a sustained way, several authors propose the elimination of the shrubby layer, respecting the components of the arboreous strata. This practice would produce a higher fodder yielding, but how it would affect the trees has not been sufficiently studied. The goal of the present work was to assess the effect of the elimination of the shrubby layer over the growth of Prosopis flexuosa D.C., the main arboreous component of the present vegetal communities of the region. The work was carried out in two sites west of Córdoba. The shrubby layer was eliminated in both of them, 12.5 ha in one plot and 4 h in the other, leaving the same amount of surface without treatment to control in each case. During 1994 and 1995 we did dendroepidometric works. Difference was made between trees of different diametric classes and condition facing intra-specific competence. The growth factors foreign to the treatment were disregarded. Calculating the theoretic growth model it was possible to compare the differences in growth in the basal, real and theoretic area between the treated plot and the control plot. The conclusion was that the elimination of shrubs increased the growth of the basal area of the trees in both plots. There were not different responses among trees of different diametric class and condition of intra - specific competence. The response to the treatment was noticeably different in both sites, possibly because of the different methodology used to eliminate the understory (manual and mechanic) and to having sowed a high yielding pasture in one case.

Keywords : Agroforestry systems; Shrub elimination; Prosopis flexuosa; Individual growth.

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