Influence of silvicultural treatments on growth of mature mesquite ( Prosopis glandulosa var. glandulosa) nine years after initiation

Abstract

The growth of a mature stand of Prosopis glandulosa was measured 9 years after thinning, understorey removal, understorey removal plus herbicide resprout treatment, and phosphorus fertilizer treatments had been applied. The volume and weight of growth were estimated with dendrometers installed at the base of 20% of the trees, and regression equations were calculated that related basal area to volume and weight. Mean absolute growth increases were not significantly different among the treatments ( P > 0.05). However, when volume and biomass growth were compared with difference in initial basal area, some of the treatments were significantly different. The understorey removal + thinning + herbicide + fertilizer treatment resulted in the greatest mean percent weight growth (28.3%, n = 4, SD = 3.0647) and percent volume growth (34.9%, n = 4, SD = 3.9790) over the 9-year time-period, and was significantly ( P = 0.0001) different from the control percent weight (11.1%, n = 4, SD = 0.5315) growth and control volume (13.3%, n = 4, SD = 0.7124) growth. The annual diameter increment for the fertilizer treatment was 0.27 cm year −1, n = 4, SD = 0.898, which is comparable with other mature commercial hardwood forests.