A mixed-effects height-diameter model for cottonwood in the Mississippi Delta

Abstract

Eastern cottonwood (Populus deltoides Bartr. ex Marsh.) has been artificially regenerated throughout the Mississippi Delta region because of its fast growth and is being considered for biofuel production.This paper presents a mixed-effects height-diameter model for cottonwood in the Mississippi Delta region. After obtaining height-diameter measurements from the plot/stand of interest, a mixed-effects model can be calibrated often improving height estimates relative to an uncalibrated fixed-effects model. When using an independent validation dataset, the calibrated mixed-effects height-diameter model vastly improved height predictions compared to a completely fixed-effects model. When using only one tree in calibration, bias decreased from -1.1164 m to -0.1334 m while the mean square error (MSE) decreased from 2.3421 to 0.4869 for the fixed-effects and mixed-effects models, respectively. When using three trees in calibration, the bias and MSE were reduced to -0.0495 m and 0.3012. The use of three trees in model calibration will likely provide a reasonable compromise between predictive ability and field sampling times.

Parent Publication

• Proceedings of the 16th biennial southern silvicultural research conference

Citation

VanderSchaaf, Curtis L.; Stuhlinger, H. Christoph. 2012. A mixed-effects height-diameter model for cottonwood in the Mississippi Delta. In: Butnor, John R., ed. 2012. Proceedings of the 16th biennial southern silvicultural research conference. e-Gen. Tech. Rep. SRS-156. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 352-358.