Root growth of Quercus crassifolia, Q. crassipes, and Fraxinus uhdei in 2 different soil types

Abstract

Seedlings of selected tree species were grown in small benchtop rhizotrons filled with fine- and coarse-textured soils representing 2 different urban edaphic conditions in Mexico City. Bulk density was significantly higher and porosity was significantly lower in the coarse-textured soil. The maximum depth of root penetration visible behind the glass was significantly greater in the fine-textured soil for each of the 3 species after 5 months. Roots of Fraxinus uhdei penetrated deeper than roots of both Quercus crassipes and Q. crassifolia in both soils. Fraxinus uhdei root and shoot dry weight were significantly reduced in coarse-textured soil compared to the fine-textured soil, but both Quercus species were unaffected by soil type. In the fine-textured soil, F. uhdei root and shoot dry weight was significantly greater than both Quercus species, but not in the coarse-textured soil. At the end of the study, F. uhdei growing in fine-texture soil were taller than F. undei growing in coarse-textured soil and taller than both Quercus species in both soils, though the difference took 6 weeks longer to develop in the coarse-textured soil.