Response to cutting of Larrea divaricata and L. cuneifolia in Argentina

Abstract

The response of Larrea divaricata and L. cuneifolia to cutting stems 0-20 cm above the ground was studied in the arid piedmont area west of Mendoza, Argentina. The species occur at different elevations and in vegetation zones: L. cuneifolia < 1250 m; L. divaricata between 1250 and 2500 m. Four treatments with 10 replicates were analysed in randomly chosen plants: cut at ground level with lopping shears; cut at ground level with a pick; cut at 10 cm with lopping shears; and cut at 20 cm with lopping shears. The initial and final height, volume, and dry matter (above- and below-ground) were determined. The relation between volume and initial and final dry matter and height was analysed through a factorial MANOVA (p < 0,05), and the functional relation between volume, dry matter and height was estimated by adjusting a regression model. In both species, maximum recovery was reached when cut with shears, and predicted recovery (turnover) was 17-18 yr. In the two last treatments height was a useful predictor of dry matter. L. divaricata-dominated plots have a lower biomass, growth rate, and allocation to stems and root than L. cuneifolia-dominated plots. Regrowth following clipping on an area of 3-10 ha, is sufficient to support the annual needs (cooking and heating) of one family.