Reforestation Costs can be decreased by lowering initial stocking and outplanting morphologically improved seedlings

Abstract

Two stock types of loblolly pine (Pinus taeda L. [Pinaceae]) were outplanted at 3 spacings: 749, 1122, and 1497 trees/ha (303, 454, and 605 trees/ac). Morphologically improved seedlings were grown at a density of 177/m² (16/ft²) while standard seedlings were grown at a density of 277/m² (25/ft²). Morphologically improved seedlings had an average root-collar diameter of 6.3 mm at time of outplanting and, after 3 y in the field, were taller and had more volume/ha than standard seedlings (4.5-mm root-collar at outplanting). An economic analysis was conducted based on 20-y volume estimates from a growth and yield program. If seedling cost is increased by 0.7 cent (due to growing at a low seedbed density) then out-planting cost per ha can be reduced by outplanting 750 morphologically improved seedlings instead of 1500 standard seedlings. Overall establishment costs might be reduced by US$ 108/ha ($44/ac) and the net present value of the stand might be increased by 10% or more (due to increasing the production of sawlogs). From this and other analyses, we determined that an important economic relationship exists between outplanting density and seedling quality.