AN 8-YEAR FIELD COMPARISON OF NATURALLY SEEDED TO PLANTED CONTAINER PINUS-TAEDA, WITH AND WITHOUT RELEASE

A field study compared genetically improved, container loblolly pines (Pinus taeda L.) with naturally seeded loblolly pines through eight gr owing seasons on a cutover site in southern Arkansas, U.S.A. Measureme nt pines on 6 of 12 plots were released from woody and herbaceous comp etition within a 61-cm radius of each tree stem. On natural pine plots , only Ist-year pine seedlings were selected for measurement based on quality standards and their spacing. Woody competition was controlled by hand cutting for 5 consecutive years, and herbaceous competition wa s controlled with herbicides for 4 consecutive years. Release treatmen ts increased 8-year survival by 50% for natural pines and by 35% for p lanted pines. Greater gains (343-391%) in individual tree volumes were achieved within regeneration techniques, as a result of release, than were achieved with the two regeneration techniques. In addition, stan d volume gains of 647% and 910% were achieved by planted and natural p ines, respectively, as a result of release. Eight years after field es tablishment, stand volume index averaged 46% higher on planted plots t han on natural plots. Degree of overtopping was a better predictor of pine performance than live-crown ratio.