Planting Deep Increases Early Survival and Growth of Pinus echinata Seedlings

Two studies were established to determine the effects of planting depth on early performance of bareroot shortleaf pine seedlings (Pinus echinata).The studies involved planting seedlings either with the root-collar slightly below the groundline (GL) or with the root-collar planted about 11 cm below the soil surface (DEEP).After transplanting, DEEP seedlings had about 7.9 cm of shoot remaining aboveground.In one study, seedlings were planted in open sand pits where seedlings received 352 mm of rain by April 30.The second study involved planting seedlings in boxes (containing sand) in a roofed shade-house.Without rain, survival of DEEP seedlings in April was 96% which was significantly greater (P>F =0.007) than survival of GL seedlings (67%).With rainfall, survival (95%) was the same for both planting depths (P>F = 0.39).Therefore, planting seedlings with the root-collar level with the soil surface can, in some years, increase mortality.This might help explain why bareroot survival of shortleaf pine in some forest districts averages less than 80%.