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Management intensity and genetics affect loblolly pine seedling performance

Informally Refereed

Abstract

Capturing potential genetic gains from tree improvement programs requires selection of the appropriate genetic stock and application of appropriate silvicultural management techniques. Limited information is available on how specific loblolly pine varietal genotypes perform under differing growing environments and management approaches. This study was established in 2008 to examine the performance of two selected loblolly pine varieties (crop vs. competitor) at different initial planting spacings and management intensities. The two genotypes were selected based on their putative divergent crown architectures. After three growing seasons, neither initial spacing nor management intensity had any effect on tree survival. Survival of the crop tree genotype (98.0 percent) was significantly greater than that of competitor genotype (86.3 percent). Growth of surviving seedlings was affected by both genetics and management intensity. Mean year-three height of the crop genotype (8.4 feet) was significantly greater than that of the competitor genotype (7.3 feet). Mean year-three height in the high intensity management plots (9.3 feet) exceeded that on the low intensity management plots (6.5 feet). Differences in levels of competition between high and low intensity plots, while not affecting survival, appear to have had the greatest impact on seedling height growth. Somewhat surprisingly, the crop tree genotype outperformed the competitor genotype in both survival and height growth.

Parent Publication

Citation

Roberts, Scott D.; Rousseau, Randall J.; Herrin, B. Landis. 2012. Management intensity and genetics affect loblolly pine seedling performance. In: Butnor, John R., ed. 2012. Proceedings of the 16th biennial southern silvicultural research conference. e-Gen. Tech. Rep. SRS-156. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 259-263.
https://www.fs.usda.gov/research/treesearch/41455