Background/Question/Methods
Liriodendron tulipifera is prolific throughout the Southeastern United States and has increasingly important roles in forestry and wood products in this region.  The relatively low density and intermediate strength of the wood makes L. tulipifera versatile for use in wood products.  Little is known about the genetic makeup of this species and genetic polymorphisms throughout its native range. This study utilizes a molecular marker technique, amplified fragment length polymorphism (AFLP), to determine the degree of genetic polymorphism of L. tulipifera throughout its range. In addition to identifying genetic polymorphisms this study addresses correlations of genetic polymorphisms with variations in wood density. Due to the interrelatedness of environmental factors and genetics in determining phenotypes, this study seeks to examine the role of genetic polymorphisms in wood density of L. tulipifera. Wood density was determined using an X-ray densitometer to scan tree cores.  AFLP was performed using five primer combinations on samples from plots within six study sites.  The study sites include unmanaged stands in Mississippi, North Carolina, Ohio, South Carolina, Tennessee, and Virginia. Sites are characterized by physiographic region, and latitude/longitude.
Results/Conclusions
The range of average wood density for L. tulipifera is greater in the mountains, 389.1 kg/m³ to 475.3 kg/m³, than in the coastal plain, 404.33 kg/m³ to 466.34 kg/m³. Significant differences in wood density between sites range from 86kg/m³ to 31kg/m³. The highest levels of genetic differences are expected within populations, with the Virginia Coastal Plain site having a Dice coefficient of 0.9087.  The highest levels of inter site genetic differences are expected between the mountain sites of highest latitude and coastal plain sites of lowest latitude.