Abstract
Growth and yield models used to evaluate midrotation fertilization economics require adjustments to account for the typically observed responses. This study investigated the use of age-shift models to predict midrotation fertilizer responses. Age-shift prediction models were constructed from a regional study consisting of 43 installations of a nitrogen (N) by phosphorus (P) factorial experiment established in midrotation loblolly pine stands in the Southeast United States. Ten years of data indicated that, with time after fertilization, the age-shifts increased to an asymptote. The asymptote and the time to reach it were functions of the rate of fertilizers applied, as well as initial stand parameters including initial stocking, dominant height, stand age and basal area. The methodology was verified with an independent data set.
Parent Publication
Citation
Carlson, Colleen A.; Fox, Thomas R.; Allen, H. Lee; Albaugh, Timothy J. 2010. Applying the age-shift approach to model responses to midrotation fertilization. In: Stanturf, John A., ed. 2010. Proceedings of the 14th biennial southern silvicultural research conference. Gen. Tech. Rep. SRS–121. Asheville, NC: U.S. Department of Agriculture, Forest Service, Southern Research Station. 379-382.
