Soil Moisture Uptake by Green Ash Trees After Transplanting

Abstract

Abstract Forty-five Summit green ash trees (Fraxinus pennsylvanica Marsh. ‘Summit’) were planted on a compacted clay soil site. Unamended soil, amended soil, and friable topsoil were used as backfill, in combination with holes slightly larger than the root ball, twice, and 3 times the diameter of the root ball. Soil moisture tension (SMT) was monitored in the root ball, in the backfill, and outside of the planting hole. Soil moisture tension reached at least −50 KPa within the root ball in as little as two days. Improved backfill soil and large planting holes resulted in earlier significant uptake of soil moisture outside of the root ball compared to nearby soil where roots were excluded. SMT inside the root ball were significantly more negative than the surrounding soil for all treatments until twenty weeks after transplanting. At 68 weeks after transplanting, differences in SMT between the root ball, the backfill, and the soil outside the planting hole became insignificant for all treatments. Soil moisture tensions levels reported to inhibit root growth were frequently measured in the root zone throughout the first two growing seasons after transplanting.