PARENT SESSION
Oral Session #13: Plant Ecology: Light Relationships. Presiding: J. Rebbeck.
Monday, August 6, 2001. 1:00 PM to 4:30 PM. Hall of Ideas P&Q.
How differently do seedlings of Quercus alba, Q. prinus and Q. rubra respond to low light intensities created by shading?
REBBECK, JOANNE1, GOTTSCHALK, KURT 2, SCHERZER, AMY1, 1 2
ABSTRACT- Inadequate competition for light and nutrient resources with faster-growing species contributes to the poor regeneration of oak species. In fall 1998, chestnut, red, and white oak acorns were collected from five sites in WV. After planting in spring 1999, potted seedlings (total n: chestnut = 447, red = 525, & white = 216) were grown within one of three shade treatments (25, 18, and 6% of full sun) in one of two native forest soil mixes (OH or WV). In August 1999, midday photosynthesis (Pmax) of all species was not significantly impacted by shading or soil. In August 2000, chestnut Pmax was 51 and 12% higher in 25 and 18% light respectively, than those in 6% light (p=0.13). Red oak Pmax was 14 and 10 % higher in 25 and 18% light respectively, than those in 6% light(p=0.19). White oak growth was not affected by shading or soil in either season, while red and chestnut oak height significantly increased linearly with increasing light levels. After two seasons, chestnut and red oaks grown in 25% light were 
27% taller than seedlings grown in 6% light. Stem diameter of chestnut and red oak seedlings grown in 25% light was 35% (p=0.01) and 25% (p=0.03) greater respectively, than those grown in 6% light. Soil effects were limited. Overall, white oak appears to be less responsive to light than either chestnut or red oak.
KEY WORDS: oak regeneration