Effects of Soaking in Water on Acorn Germination of Four Southern Oaks

Greenhouse germination tests were run on acorns of Quercus falcata Michx., Q. phellos L., Q. laurifolia Michx., and Q. lyrata Walt. Q. falcata is typical of moderately dry upland sites, the others of southern bottomland types. Q. lyrata occupies the wettest sites. Acorns were pre-soaked in distilled water for four different periods at two different temperature levels to approximate normal ranges during winter and spring flooding. There were no conclusive effects on total germination; germination of treated Q. falcata and Q. phellos at 30 days was either unaffected or slightly reduced with no consistent pattern of soaking time-temperature effects, but with poorest germination after the longest soaking period at the lower temperature level. Germination of Q. laurifolia at 30 days was, with an exception, either unaffected or slightly increased; maximum increase followed the longest soaking period at the highest temperature level. Germination of Q. lyrata was severely delayed by all treatments which seems to be related to saturation of the spongy shells with consequent interference in gas exchange. If flooding is the principal factor preventing regeneration of certain oaks on wet sites it is most limiting after germination.