Variation in loblolly pine ring microfibril angle in the southeastern United States

The effect of physiographic region on microfibril angle (MFA) in loblolly pine ( Pinus taeda L.) in the southern United States was evaluated. MFA was determined at 1.4, 4.6, 7.6, 10.7, and 13.7 m up the stem of 59 trees, representing five physiographic regions. A nonlinear mixed-effects model was developed to test for regional differences in the initial value of MFA, the rate at which MFA changes with ring number from pith, and the lower bound of MFA achieved. Our results suggest that the parameters of interest differ significantly by region. It was found that MFA differs significantly between the South Atlantic, Gulf, and Hilly regions, compared to the North Atlantic and Piedmont regions. The initial value of MFA was found to be smaller in the Piedmont compared to all other regions. Similarly, the rate at which MFA changes with ring number was found to be significantly smaller in the North Atlantic and Piedmont regions. A test of the lower bound of MFA indicates that the Piedmont region has a significantly larger lower asymptote. These results combined indicate that overall, MFA values are larger in the North Atlantic and Piedmont regions.

[1]  Robert L. Bailey,et al.  Modeling and Prediction of Forest Growth Variables Based on Multilevel Nonlinear Mixed Models , 2001 .

[2]  Yuedong Wang.  Mixed effects smoothing spline analysis of variance , 1998 .

[3]  Margaret T May,et al.  Statistical Methods for the Analysis of Repeated Measurements.Charles S Davis. Heidelberg: Springer Verlag, 2002, pp. 415, £59.50 (HB) ISBN: 0-387-95370-1. , 2003 .

[4]  Robert A. Megraw,et al.  Wood Quality Factors in Loblolly Pine: The Influence of Tree Age, Position in Tree, and Cultural Practice on Wood Specific Gravity, Fiber Length, and Fibril Angle , 1997 .

[5]  A. Clark,et al.  Multilevel Nonlinear Mixed-Effects Models for the Modeling of Earlywood and Latewood Microfibril Angle , 2005 .

[6]  E. Macdonald,et al.  A review of the effects of silviculture on timber quality of Sitka spruce , 2002 .

[7]  A. Clark,et al.  Variation in Loblolly pine cross-sectional microfibril angle with tree height and physiographic region , 2006 .

[8]  C. Lundgren.  Microfibril angle and density patterns of fertilized and irrigated Norway spruce , 2004 .

[9]  D. Bates,et al.  Nonlinear mixed effects models for repeated measures data. , 1990, Biometrics.

[10]  Timothy G. Gregoire,et al.  A non-linear mixed-effects model to predict cumulative bole volume of standing trees , 1996 .

[11]  V. Carey,et al.  Mixed-Effects Models in S and S-Plus , 2001 .

[12]  J. C. F. Walker,et al.  Stiffness of wood in fast-grown plantation softwoods: the influence of microfibril angle. , 1994 .