Advantages of Using Selected Seed Sources of Sycamore and Sweetgum for Field Nursery Production and Transplant Establishment

Adaptability of forest tree improvement program seed sources to landscape nursery production and subsequent bare-root transplanting were investigated. Growth during two years of field production of seedlings from two elite half-sib families of sycamore (Platanus occidentalis L.) and a bulk open pollinated seed orchard mix of sweetgum (Liquidambar styraciflua L.) were compared with a commercially available seed source of sweetgum and a locally collected half-sib family of sycamore. Utilization of select half-sib families of sycamore resulted in 11% to 19% increases in height and an 11% increase in caliper during field production compared to the local seed source. Seedlings from elite half-sib families of sycamore resumed limited height and caliper growth during the year following transplanting while seedlings from the local seed source did not. Less pruning cuts were required to remove multiple leaders and large basal suckers on elite sycamore and sweetgum seedlings during production.