Effect of duration of stratification on growth and chemical properties of Ash (Fraxinus excelsior L.)

Cold stratification is widely used to break dormancy of ash (Fraxinus excelsior L.) seeds. In this study, two groups of seedlings produced by two treatments of ash seeds, one and two-years cold stratification of seeds were investigated with three replications in a completely randomized design in samples of one m2 per plot. Some quantitative characteristics of seedlings including collar diameter, leaf area, stem length, root length, crown height and its biomass and leaves chemical characteristics including organic carbon, nitrogen, phosphorus, potassium and relationship between carbon to nitrogen are examined. The results showed that seedlings density from the two-years old seeds (average of 157.67 seedlings per m2) was significantly higher than that of one-year treatment seeds (average of 61.67 seedlings per m2). Also significant difference between two stratification treatments was recognized for collar diameter, crown diameter, crown height, total height, root length and leaf area index; which were higher values in two years’ cold stratification treatment. Among the chemical characteristics of leaves, only potassium content showed significant difference which was higher in the two years’ cold stratification treatment. In general, we conclude that cold stratification on seed of ash for two years ensure the successful production of ash seedlings in nurseries.