Fraxinus Excelsior L.

Abstract

F. excelsior is common on soils of high base status, and frequently forms virtually pure woods on calcareous sites. Effective reproduction is by seed, which ripens in Sept. The embryos continue to elongate during their 1st summer on the ground and finally germinate after the following winter. Though the seedlings will not survive beneath dense vernal field layers, they tolerate shade from deciduous trees by completing most of their growth before the canopy foliage is fully expanded; growth studies are cited to support this. Best growth of Fraxinus occurs over the soil pH range of 5-8, where the trees are not exposed to strong winds and drought. Fraxinns is sensitive to spring frost, and drought causes early leaf-fall. The width of annual rings is closely correlated with rainfall in May and June. There are distinct differences between adult and juvenile shoots in morphology and behavior. The rootlets, which show differentiation into 2 types, occur in greatest concentration in the top 5 cm of soil, up to 1500 cm having been measured in soil samples of 85 cc. Some 47 predators and parasites are listed, a number of which contribute to the severe reduction in numbers during establishment phases.