May 21, 2020
https://www.linkedin.com/posts/activity-6669426243995230208-Dg4i
A crown width-diameter growth projection system for green ash was developed by using data from a crop tree enhancement study in a 16-year old bottomland site in Tennessee. Treatments included release, release with fertilization, and control. The crown width (CW) projection function uses initial CW and initial height, and includes response to release treatments with or without fertilization The dbh projection function uses initial dbh, periodic CW growth, and depth to mottling (depth to seasonal groundwater). The CW and dbh projection functions were fit as a system of seemingly unrelated regression (SUR) equations that accounted for 60.5% and 84.9% of the variation, respectively.
Maximum CW growth occurs when initial CW=6.6 ft in unreleased stands and when initial CW=12.0 ft in released stands. The effects of CW growth on dbh growth vary with depth to mottling (DM), with maximum dbh growth when DM=15 in. The graphs show periodic annual dbh growth for initial dbh for control and release treatments at 3 initial crown widths and 3 depths to mottling. These relationships suggest that CW growth is an indicator of interspecific competition, which is strongly influenced by seasonal groundwater that is greater than 22 in. deep and, to a lesser extent, less than 10 in. deep.