An Evaluation of Soil Aeration Status around Healthy and Declining Oaks in an Urban Environment in California

Abstract

Examination of soil conditions around healthy and declining oak trees in an urban area in California revealed that soil aeration in the upper soil strata was critical to tree vigor. It also was found that measurements of oxygen diffusion rate gave a better indication of oxygen availability in soil than measurements of oxygen concentration. Oxygen diffusion rate was lowest in soils with high bulk density and high soil moisture content. In a poorly-aerated soil, oxygen diffusion rate did not increase significantly following air injections designed to loosen soil structure.