Management intensity and genetics affect loblolly pine crown characteristics
This article is part of a larger document. View the larger document here.Abstract
The development of elite loblolly pine (Pinus taeda L) genotypes may lead to reduced planting densities as a means of reducing establishment costs. However, this can lead to undesirable crown and branch characteristics in some genotypes. Selecting appropriate genetic material, combined with appropriate silvicultural management, is essential to realizing potential genetic gains. A study was established in 2008 to examine the performance of two loblolly pine varieties, a “crop tree” ideotype and a “competitor” ideotype, at different initial tree spacings and management intensities. After two growing seasons, genetics were already affecting crown morphology. The crop tree ideotype was, on average, taller, had longer and wider crowns, greater crown volume, and less acute branch angles. Management intensity had greater impact on crown characteristics than genotype. Intensive management resulted in trees that averaged over 1.1 ft (~24%) taller with wider crowns (0.7 ft, 30%), longer crowns (0.9 ft, 32%), and greater crown volume (5.5 ft3, 133%) relative to non-intensive management. Differences due to management intensity were related to reduced crowding from competing vegetation and lower incidence of damage from pine tip moth and sawfly.