• Taylor, Fred W.
  Mississippi Forest Products Laboratory, Mississippi State, MS
  
• Burton, James D.
  U.S. Forest Service, Southern Forest Experiment Station, Pineville, LA
  

Intensive thinning, understory control and green pruning of loblolly pine trees growing on a test area near Crossett, Arkansas, have produced trees with a diameter of 18.9 inches at breast heights in 35 years. Large increment borings extracted from experimental trees and control trees were examined for growth patterns and wood properties alterations related to growth rate differences. During some growth periods, radial growth of test trees was almost three times as great as radial growth of control trees. In the outer juvenile wood formed after the first thinning, growth rate differences were greatest between experimental trees. During the last 10 years of the study (mature wood zone), growth rate differences between treated and control trees were not as great, and there were no significant differences in latewood percentage or tracheid length. Specific gravity was not significantly influenced by growth rate differences in any growth zone. This result leads to the conclusion that trees can be rapidly grown without affecting specific gravity.