Document: CYN-3-68-6

Experimental studies of fire temperature on oak ( Quercus) seed germination in Appalachian mixed-oak litter.

RICCARDI, C.L.* and B.C.MCCARTHY

Ohio University, Athens, OH 45701, USA ¹

Abstract:
The relationship between wildland fire intensity, fire temperature, and the response of plant and animal populations is complex. Few studies have experimentally examined fire temperatures and oak seed germination at fine spatial scales. To examine temperature patterns characteristic of the Appalachian mixed-oak hardwood region, we exposed aluminum tags painted with temperature-sensitive paints (38-427 C) and placed them at -2, +2, and +12 cm relative to the soil surface. The sensors were arranged in 1 by 1 m grids with 25 cm spacing distances, and burned in oak litter. Below ground (<30 C) sensors were spatially homogeneous across the experimental burn plots. Sensors in the leaf litter experienced the most variable temperatures (range: 110-370 C) and greatest spatial variability. An intermediate range of spatial variability was recorded at +12cm (150-330 C). A subsequent study designed to examine fire temperature on oak seed germination used 423 Quercus prinus seeds. The treatments varied seed position (above- or below-ground), temperature (Control, 38, 66, 150, 204, & 260 C), and exposure time (5 or 15 min). Time and temperature were highly significant (P<0.001) and affected seed germination. Seed exposure to temperature above 150C for more than 5 minutes yielded decreased germination (21.3%) compared to lower temperature and time treatments (75.1%). Temperature at 204C for 15 min usually resulted in complete mortality. We hypothesize that caching of Q. prinus seed by squirrels Sciurus spp. could increase seed survival during wildland fires.

Keywords: Quercus, Oak, Appalachia, Forest, Fire, Fire temperature, Seed germination, Disturbance

This abstract is being presented at: 2:15 PM in session:
Oral Session #35: Fire Ecology.