Use of Polyethylene-covered Greenhouses to Improve the Growth of Quercus rubra Seedlings for Reforestation

Seedlings of Quercus rubra were cultivated outdoors and in a polyethylene-covered greenhouse. Their development over the first growing season was monitored and compared, taking into consideration factors such as the time of sowing (fall or spring). Height, root-collar diameter, and oven-dry mass of tops and roots were significantly greater in greenhouse-cultivated seelings. However, the differences were reduced when the seedlings were sown later in the spring. Analysis of top-root ratios showed that the balance of seedlings was not affected by greenhouse cultivation. The results of this study the rapid growth of the seedlings produced in. the greenhouse lead us to reconsider our current production standards. Key words: Grading criteria, greenhouse production, morphological quality, nursery stock. Quercus rubra, seedling production.