Abstract
Between the late 1970s and the early 1990s, the USDA Forest Service installed 155 shortleaf pine (Pinus echinata Mill.) progeny tests in national forests across the Southern Region of the United States. Using control-pollinated crosses from the Mount Ida Seed Orchard, 84 of these progeny tests were established in the Ouachita and Ozark-St. Francis National Forests in Arkansas and Oklahoma. Each of these 84 test locations had, on average, 33 full-sibling families representing three local geographic seed sources (East Ouachita, West Ouachita, and Ozark). Though largely abandoned years ago, the progeny tests that remain provided an opportunity to determine if significant genetic and genetic × environment variance exists for performance traits (d.b.h., tree height, and survival) decades after installation. In 2018 and 2019, we remeasured d.b.h. and height and determined survival in 15 fully stocked progeny tests. Family variances were significant (p < 0.01) for both d.b.h. and height but not for survival (p > 0.05). Seed sources differed significantly (p < 0.05) for d.b.h., with more pronounced latitudinal differences. Additionally, we determined that individual tree and full-sibling family mean heritabilities were moderate (0.15 and 0.72, respectively, for d.b.h and 0.09 and 0.41, for height), suggesting relatively high genetic to environmental variation and good potential for genetic improvement. We also found that shortleaf pine families were broadly adapted in this region since family-by-test variances were non-significant (p > 0.05).
Highlights
Shortleaf pine (Pinus echinata Mill.) is native to 22 states from southern New York to eastern Texas and has the largest natural range of the four major southern pines [1,2]
The replication × family interaction term for height was significant (p < 0.05) for several tests (Table 5), suggesting that family performances in these tests were largely dependent upon environmental variation. These results indicate a wide range in family performance within the sampled seed sources across the sampled test sites, suggesting an opportunity to improve the current seed orchards [17,38] based on the progeny test information
In our limited assessment of these remeasured shortleaf pine, we found about half of those on the Ouachita showed evidence (Figure 2) of injury, with the East Ouachita (EOU) test sites having the highest proportion (71.2%) of impacted trees, followed by the West Ouachita (WOU) (58.3%) and OZ (5.8%) seed source areas (Table 1)
Summary
Shortleaf pine (Pinus echinata Mill.) is native to 22 states from southern New York to eastern Texas and has the largest natural range of the four major southern pines [1,2]. Over the last half-century, shortleaf pine has experienced a significant decline in coverage area and importance across its range, with a dramatic decrease between 1980 and 2013 [9,10,11,12]. While this decline is especially prominent in Piedmont, East Gulf Coastal Plain, and the southern Appalachians, it has been noticeable in the western part of shortleaf pine’s range, where the species tends to be most prominent [13]. Decades of changes to fire regimes (leading to more hybridization with loblolly pine and insufficient natural regeneration), selection bias in harvest treatments, and other unfavorable forest management practices (e.g., preferential planting of loblolly pine on shortleaf pine sites) have all greatly reduced shortleaf pine abundance [9,12,14]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
