A Modified Stand Table Projection Growth Model for Unmanaged Loblolly and Slash Pine Plantations in East Texas

摘要

Four methodologies to project future trees per acre by diameter class were compared to develop a new modified stand table projection growth model for unmanaged loblolly pine (Pinus taeda L.) and slash pine (Pinus elliottii Engelm.) plantations in East Texas. The new models were fit to 92,882 observations from 153 permanent plots located in loblolly pine plantations and 33,792 observations from 71 permanent plots located in slash pine plantations throughout East Texas. The new models were validated with 12,750 observations from 22 permanent plots and 3,724 observations from 9 permanent plots located in loblolly and slash pine plantations, respectively. The validation data were used to select between the four methodologies. The results indicated which of the new models produced the best results, based on error indexes calculated for trees per acre and basal area per acre at the stand table and diameter class levels across a range of projection lengths. We recommend that this new model be used by forest managers for projecting stand tables in East Texas loblolly and slash pine plantations. An example is also provided to show users how to use the new modified stand table projection model.