Culture and Genetic Variation Influences on Juvenile Wood Properties of Slash and Loblolly Pines in Florida

The effects of four cultural levels (conventional site preparation and bedding, maximal fertilization, complete vegetation control, and combined fertilization and vegetation control) on latewood percent, age of transition from juvenile to mature wood, and wood specific gravity of young slash and loblolly pines were first evaluated by extracting lower stem cores from 200 10-year-old trees on a flatwoods site near Gainesville, Florida. Latewood percent, which increased from ring ages 4 to 10 years, tended to increase with intensive culture, particularly in slash pine. Under the intensive cultures, slash pine formed mature wood starting at age seven, whereas loblolly pine did not typically form >50 % latewood until nine years. No slash pine progeny formed mature wood before age seven, but two progenies tended to deposit more latewood at all ages. Findings on transition age generally confirm previous indications that slash and loblolly pines form mature wood earlier with decreasing latitude. Specific gravity in rings 6-10 was not related to tree DBH, total height, or height to live crown. A second sampling of 80 13-year-old trees using stem disks at 1.5m indicated a trend toward insignificantly lower specific gravity with intensive culture. Previous latewood and transition age patterns persisted. In both samples, slash pine had insignificantly higher specific gravity than loblolly pine in three cultures and overall. Variability between species and within slash pine for important wood properties may offset some undesirable wood quality changes resulting from culturally induced faster growth.

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Author(s): Donald L. Rockwood, Joseph R. Saucier, Alexander Clark, III

Publication: Tree Improvement and Genetics - Southern Forest Tree Improvement Conference - 1997

Section: Contributed Presentations: Full Papers