Relative Growth and Water Use of Seedlings from Three Italian Quercus Species

A species' water use characteristics and growth habits are important to urban foresters. Seedlings from three species (and two sources)-Quercus cerris L., Q. pubescens Willd., and Q. robur L.-were container-grown and subjected to a three day water use trial under nonlimiting soil moisture conditions. Water use varied among species and between sources within a species. Larger seedlings used more water than smaller seedlings*Q. robur seedlings were the tallest, 70.5 cm (27.8 in), and had the greatest water use seedling, 73.4 g (2.5 oz) water, while Q. pubescens and Q. cerris seedlings were shorter, 46 and 45 cm (18.1 and 17.7 in), and averaged 47.5 and 44.9 g (1.68 and 1.58 oz) water, respectively. Quercus pubescens seedlings had the highest water use cm2 leaf area (0.111 g)*Q. cerris seedlings had the highest height-adjusted water use (1.4 g water cm'1 height). There were significant differences in water use between sources within species. Principal component analysis, using 20 variables, showed that seedlings of Q. robur and Q. pubescens sources clustered while seedlings of the two Q. cerris sources were separate from each other and the Q. robur and Q. pubescens sources. The clustering reflected the proportionally greater distribution of dry weight to shoot growth and correspondingly less to root growth of the Q. robur and Q. pubescens seedlings, than that for Q. cerris seedlings. The results are related to the species' relative value to nursery producers and to the potential value to urban forest managers and the potential for cultivar development.