Tree root system enhancement with paclobutrazol

Abstract

Paclobutrazol 2SC (PBZ) was injected into the soil at the base of the trunk at 2 g a.i. per inch dbh. Surface fine root densities near the base of the trees were naturally higher than in the rest of the root system and were adequate to absorb the compound. PBZ treatment was effective in stimulating fine root development in pin oaks (Quercus palustris) and white oaks (Quercus alba). Pin oak fine root densities were increased significantly in high-quality topsoil. White oak fine root densities were increased significantly by PBZ alone and in combination with high-organic replacement soils. The treatment may be effective in stabilizing declining trees with insufficient fine root development.