The ability of an organism to survive and grow in an environment is partly controlled by the organism's genotype. The influence of genotype on seedling survival and the large amount of genetic variability within forest tree species has, in part, led the U.S.D.A.-Forest Service, in cooperation with many state forest agencies, to develop seed zones. Seed zone delineation is an attempt to prevent using seedlings from unfit or non-adapted seed sources on a planting project. A current approach in

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... orestation involves matching planting stock type to site conditions and developing a planting stock with attributes best suited to the site. This system is often referred to as a target seedling system. One target parameter often used is the overall seedling size. The influence of seedling size on reforestation and afforestation success has been well documented. The objectives of this study were to examine the influence of seed source or genotype, and stock size on transplant success of seedlings transplanted directly into overburden piles at the Molycorp Mine in northern New Mexico. Four sources of ponderosa pine (Pinus ponderosa Doug!. ex Laws.), two northern New Mexico and two southern New Mexico seed sources were evaluated. Seedlings from each seed source were produced in three different container sizes, 16.4 cm', 115 cm 3 and 164 cm 3 containers to generate three stock sizes. Two planting sites were used at the mine. The overall study design was a randomized complete block design within an overall split plot design with planting sites being main plots. First year survival and covering of seedlings by overburden movement on the rock pile slopes were recorded. Data were analyzed using categorical model analysis with treatment comparisons utilizing a Bonferroni adjustment to reduce the likelihood of making a Type I error. Overall, survival was low (<35%) with the smallest stock sizes having the lowest survival. Smaller seedlings had greater losses (39%) due to covering than did the mid and large size seedlings, 29 and 32%, respectively. Seed source did not influence survival or covering responses. Additional