Underplanted shortleaf pine seedling survival and growth in the North Carolina PiedmontThis article is part of a larger document. View the larger document here.
A study was established in North Carolina to evaluate the viability of underplanting shortleaf pine (Pinus echinata Mill.) seedlings beneath a residual hardwood overstory as a method of reestablishing the shortleaf pine component to Central Appalachian Piedmont sites. Twenty-eight treatment plots were harvested to retain one of four residual overstory basal areas (RBA): 0, 15, 30, or 45 square feet per acre. Three shortleafpine stock types were established within the RBA treatment plots; bareroot stock (BR), and containerized stock with small plugs (SP), and large plugs (LP). Overstory basal area affected survival only in the RBA0 plots which had the poorest survival for all three stock types over the first growing season. Seedling growth declined with increasing overstory basal area for all three stock types over the second growing season. Significant differences in percent survival were also noticed between the three stock types. The LP seedlings had the highest survival and the BR the lowest. Containerized seedlings achieved superior height and groundline diameter growth across all treatments but the differences were greatest between the LP and BR seedlings. Comparatively low survival in the RBA0 plots and the inverse relationship between overstory basal area and growth are attributed to gradients in overstory and understory competition levels and site harshness acrossthe four RBA levels. The superior growth and survival of containerized seedlings is attributed to more intact root systems with higher root mass although we cannot rule out seed source differences. The results of this study suggest that underplanting may be a suitable regeneration option for the initial establishment of shortleaf pine on marginal Central Appalachian Piedmont sites. Further improvements in seedling survival and growth may be realized by planting containerized seedlings.