SOIL SEED BANK OF A JACK PINE (PINUS-BANKSIANA) ECOSYSTEM

The soil seed bank (seed and vegetative propagules) of a jack pine (Pi nus banksiana Lamb.) ecosystem was investigated using direct propagule emergence from soil cores in greenhouse experiments, and visual exami nation of rhizome/rooting systems in situ. Of the 985 emergents observ ed from soil cores 643 (65%) originated from seeds whereas 342 (35%) a rose from rhizomes. Grasses and sedge comprised 89% of the seed emerge nts while shrubs comprised 75% of the vegetative emergents. In situ ex amination of root systems revealed that Linnaea borealis L., Carer hou ghtonii Torr., Gaultheria procumbens L., and Maianthemum canadense Des f. had rhizomes buried at or above the duff/mineral interface while Ly copodium obscurum L., Lycopodium complanatum L. and Pteridium aquilinu m L. (Kuhn) were predominately buried within the upper- layers of mine ral soil. All other vegetatively reproducing species examined, with th e exception of Rubus alleghaniensis Porter, had rhizomes buried deeper than 25 cm into mineral soil. Rubus allegheniensis (reproductive root s) had no discrete area of burial and were located in duff, upper mine ral, and deep mineral soil. Depth of burial of reproductive material i s used to explain plant succession after disturbance.