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Description. Fraxinus pennsylvanica is a medium-sized deciduous tree reaching 12–25 metres (39–82 feet) (rarely to 45 m or 148 ft) tall with a trunk up to 60 centimetres (24 inches) in diameter. The bark is smooth and gray on young trees, becoming thick and fissured with age. The winter buds are reddish-brown, with a velvety texture.
White ash leaves turn yellow or red in autumn. Despite some overlap, the two species tend to grow in different locations as well; white ash is a forest tree that commonly occurs alongside sugar maple while green ash is a pioneer species that inhabits riparian zones and disturbed areas.
Fraxinus latifolia is a medium-sized deciduous tree that can grow to heights of 20–25 metres (65–80 feet) in height, with a trunk diameter of 40–75 centimetres (16–30 inches) in its 100−150-year average life span. [4] Oregon ash can grow considerably larger and can have well over a 200-year life span, or become stunted and very small ...
Sorbus americana is a relatively small tree, reaching 12 metres (40 ft) in height. [5] The American mountain-ash attains its largest specimens on the northern shores of Lake Huron and Lake Superior. [6] It resembles the European mountain-ash, Sorbus aucuparia. Light gray, smooth, surface scaly. Branchlets downy at first, later become smooth ...
Hymenoscyphus fraxineus is an ascomycete fungus that causes ash dieback, a chronic fungal disease of ash trees in Europe characterised by leaf loss and crown dieback in infected trees. The fungus was first scientifically described in 2006 under the name Chalara fraxinea. Four years later it was discovered that Chalara fraxinea is the asexual ...
Candidatus Phytoplasma fraxini. Griffiths et al. 1999. Synonyms. Ash yellows phytoplasma. Candidatus Phytoplasma fraxini is a species of phytoplasma, a specialized group of bacteria which lack a cell wall and attack the phloem of plants. [ 1] This phytoplasma causes the diseases ash yellows and lilac witches' broom.
European ash in flower Narrow-leafed ash (Fraxinus angustifolia) shoot with leaves. Fraxinus (/ ˈ f r æ k s ɪ n ə s /), commonly called ash, is a genus of plants in the olive and lilac family, Oleaceae, [4] and comprises 45–65 species of usually medium-to-large trees, most of which are deciduous trees, although some subtropical species are evergreen trees.
The reason the leaves often turn yellow before they drop is that the tree harvests many of the nutrients from the leaves before it sheds them, which is a simple measure of conservation of ...