Modeling the effect of fertilization on wood properties of loblolly pine (Pinus taeda L.)

There has been an increased interest in mid-rotation application of fertilizer in loblolly pine (Pinus taeda L.) plantation management. However concerns have arisen about the quality of wood produced following the fertilizer application. Increment cores were collected at six height levels of thirty-two trees from a thinned, fertilized stand located on lower Coastal Plain of North Carolina. The fertilization treatments selected for this study were: 1) No Nitrogen +25lb/acre of Phosphorous 2)100lb/acre of Nitrogen + 25lb/acre Phosphorous 3) 200lb/acre of Nitrogen +25lb/acre of Phosphorous 4)300lb/acre of Nitrogen + 25lb/acre of Phosphorous. Mechanical, physical and anatomical properties were measured from pith to bark and for the three years following fertilization to examine for any significant effects of fertilization on these wood properties. A three dimensional prediction equation was developed for stiffness which explains the radial and longitudinal pattern of stiffness variation within a tree. Attempts were made to develop mathematical function for stiffness responses that occurred following fertilization.