(39) Determination of the Optimum Species for Ohio Tree Liner Production in Retractable Roof Greenhouses

Abstract

Many Ohio growers import liners from the West Coast due to the increased growing season on the West Coast. Lengthening the season in Ohio may provide a way for Ohio growers to produce liners of their own. Retractable roof greenhouses (RRG) are one possible way to extend the growing season in Ohio. Research done previously at The Ohio State University suggests that retractable roof greenhouses do in fact lengthen the growing season, and tree liners can be produced using RRG. The objectives of this study were: 1) to determine the optimal growing environment from three different environments; and 2) to determine the optimal species for tree liner production in Ohio. In Oct. 2004, 180 liners each of Cladrastis kentuckea, Quercus rubra, Stewartia pseudocamellia, Syringa reticulata, and Tilia cordata were upshifted to 3-gallon pots. In Mar. 2005, 90 of each species were transferred to either a flat roof retractable house (FRRG), peak roof retractable house (PRRG), or polyhouse. Growth was measured in Mar. (initial), June, Aug., and Oct. 2005 by taking leaf area, shoot and root dry weights, height, and caliper. There were no differences across species and dates between the environments for any of the parameters measured. Tilia showed the greatest increase in growth from June to October in all the parameters measured except leaf area. Cladrastis showed the greatest increase in leaf area from June to October. There were species by date interactions. Quercus had the greatest root weight in October. Syringa and Quercus were not significantly different from each other and had the highest shoot weights and leaf areas in October. Tilia, Quercus, and Syringa had the highest calipers in October.