Gas Exchange and Growth of Transplanted and Nontransplanted Field-grown Shumard Red Oak Trees Grown with and without Organic Mulch

Abstract

Gas exchange and growth of transplanted and nontransplanted, mulched and nonmulched field-grown Shumard red oak trees (Quercus shumardii Buckli.) were investigated in a semiarid climate. In Spring 2003, 12 field-grown trees were selected for uniformity. Six trees were moved with a tree spade and six trees were undisturbed. In addition, pine bark mulch was applied around three randomly selected transplant and nontransplant trees. Soil volumetric water content, predawn leaf water potential, midday stomatal conductance (g S) and leaf temperature, and growth data were collected over three consecutive growing seasons. Throughout the experiment, weekly predawn leaf water potential and g S data indicate transplanted trees with and without mulch were under greater water stress when compared with nontransplanted trees. In addition, nontransplanted trees with mulch were under greater stress when compared with nontransplanted trees without mulch. Each year, transplanted trees and nontransplanted trees with mulch had less apical growth when compared with nontransplanted trees without mulch. Although gas exchange and apical growth of transplanted trees and nontransplanted mulched trees tended to increase each growing season, by experiment termination, gas exchange and apical growth for transplanted trees and nontransplanted trees with mulch did not recover to nontransplanted, nonmulch tree levels.