SILVICULTURAL TREATMENTS FOR SAPLING MESQUITE (PROSOPIS-GLANDULOSA VAR. GLANDULOSA) TO OPTIMIZE TIMBER PRODUCTION AND MINIMIZE SEEDLING ENCROACHMENT

To maximize lumber production and minimize weed problems with Prosopis glandulosa, silvicultural treatment methods were evaluated nine years after initiation. A randomized complete block design was used with fo ur replicates and six treatments. Plots were shredder-harvested leavin g sixteen 2-m squares on 10-m spacing that included a final rotation c rop tree. In three of the treatments the crop trees were pruned to a s ingle stem. To prevent re-establishment of mesquite in the interstitia l areas, plots were spot sprayed with herbicides, disked, or disked an d seeded with rye grass in 1986. Herbicide treatments and disking cont inued yearly through 1989. In 1991, disk treatments were repeated. Aft er both 2.5 and 9 yrs, significant treatment differences were found fo r growth of basal diameter, growth of basal area, and growth of dry we ight. The greatest crop tree growth occurred in treatments that were p runed with interstitial competition suppressed. Mortality was greatest in the dense treatments, while re-establishment of mesquite was great est in the more open treatments. The greatest basal diameter growth of 1.21 cm year(-1) in the disked and pruned treatments is comparable to other fine hardwoods in temperate and dry tropical forests. (C) 1997 Published by Elsevier Science B.V.