Research Brief #15

The Effect of Fertilization on Specific Gravity, Radial Growth,
and Juvenile Wood Proportion in a Loblolly Pine Plantation
(La Tech FPS1.2)
Louisiana Forest Products Development Center
Louisiana State University
Baton Rouge, LA

Research Objectives

Fertilization has been shown to affect wood quality; however, depending upon the manufacturing process, its effects may be beneficial or detrimental. The purpose of this project is to quantify the effect of fertilization and cattle grazing on the wood quality of plantation-grown loblolly pine.

Synopsis of Results

A l5-year-old loblolly pine plantation at the Hill Farm Research Station in Homer, Louisiana was chosen for study. Two management options were in effect, silvipasture (fertilized) and timber only (non-fertilized). Thinning was done at age 8 and pruning was done at ages 8 and 12. Cross-sectional disks were taken at the butt and at 4-foot intervals along the stem from sample trees within each management treatment. Wood quality characteristics, e.g., specific gravity, growth ring widths, latewood percentages, and Juvenile wood proportions, were measured on each disk. Preliminary results indicated indicated that silviculture management produced 30% larger dbh's and 10% taller trees. Latewood percentages, as expected, were lower in the silvipasture (fertilized) treatment. Specific gravity was slightly reduced by silvipasture management. There was no apparent difference in fiber length among management treatments. Based upon fiber length and specific gravity, the juvenility period in both management treatments was 5 to 6 years. The different management options did produce different wood quality, but their effect on wood manufacturing processes is product specific.

Progress

These preliminary results were presented at the 8th Biennial Silvicultural Research Conference, Auburn, AL, November 1-3, 1994. Further measurements of growth rate, ring-by-ring specific gravity and fiber length, and juvenile wood proportion are in progress.

Researchers

Mark D. Gibson, Associate Professor, Wood Utilization
George A. Grozditis, Research Associate
Louisiana Forest Products Laboratory
Louisiana Tech University
Ruston, Louisiana

Terry R. Clason, Professor
Forest Physiology Hill Farm Research Station
Louisiana State University Louisiana Agricultural Center
Homer, Louisiana

Target Group

Louisiana forest managers and wood products manufacturers interested in wood quality and its effect on wood processing.