Wetland habitats are important ecosystems, providing numerous ecosystem services and, when managed appropriately, valuable timber. However, there is a lack of information regarding which commercially valuable species grow better in saturated soils that characterize bottomlands. This research investigated overall growth and survivorship of 8 oak species (n=136): swamp white oak (Quercus bicolor), willow oak (Q. phellos) pin oak (Q. palustris), Nuttall oak (Q. nuttallii), overcup oak (Q. lyrata), water oak (Q. nigra), swamp chestnut oak (Q. michauxii), and Shumard oak (Q. shumardii) planted in 2004 at the University of Tennessee Research and Education Center located in Jackson, TN. Specifically, in the spring of 2018 before budburst, following 14 years of growth, diameter at breast height (DBH) and survival rates of each species was determined. Data were separated based on two saturation levels: poorly drained and moderately drained (determined by soil mottling and the depth of gleyed matrix). The DBH data were assessed comparing species and saturation level via a nonparametric Sheirer-Ray-Hare Analysis followed by post-hock analyses. Species were then ranked according to their survival percentage and mean DBHs and compared to data collected from the same trees in 2010, to determine if the growth and survivorship had changed since 2010.
Results/Conclusions
Results showed significant differences between mean DBHs according to soil saturation level (p < 0.001). Overall, species had larger DBHs when grown on moderately drained soils. However, not all trees grew better in moderately drained soils, overcup oak showed greater average DBHs when grown in poorly drained soils. A post-hock analysis showed that water oak (p < 0.001), pin oak (p = 0.003), and Shumard oak (p = 0.019), were the only species that grew significantly larger in moderately drained soil. Overall, survival ranged from 93% to 52% with swamp white oak (93%), pin oak (91%), Nuttall oak (90%), and water oak (88%) displaying the best survival rates while swamp chestnut oak (65%) and Shumard oak (52%) the worst. Some species grew significantly better in the bottomland than others (p < 0.001). With Nuttall oak (13.3 cm), willow oak (12.9 cm), overcup oak (12.9 cm), and pin oak (12.7 cm) displaying the largest mean DBHs and being significantly greater than swamp white oak (9.7 cm) and Shumard oak (8.2 cm) which displayed the smallest. These results were generally consistent to the data collected in 2010 indicating that these oak species continued to perform similar to previously recorded observations.