Germination of two warm-temperate oaks, Quercusemoryi and Quercusarizonica

Abstract

Quercusemoryi Torr. (emory oak) and Quercusarizonica Sarg. (Arizona white oak) are the dominant trees in many of the oak savannas and woodlands of Arizona and northern Mexico. The objectives of this study were (i) to evaluate germination on two media as influenced by storage and stratification and (ii) to determine the effects of oak canopy and depth of burial on acorn viability and germination. Germination was higher (P < 0.05) on filter paper than in mineral soil in laboratory trials. Maximum germination of Q. emoryi in the field was observed at a depth of 7.5 cm (29%), with only 5% germination at the soil surface. Germination of Q. arizonica at 7.5 and 15 cm (73%) was not different (P > 0.10) but exceeded germination at the surface (17%). These results represent the first reported germination of either species and indicate that recruitment into mature oak woodlands is not limited by germination.