1. Characteristics

2. Cultivation and uses

3. Emerald ash borer

4. Ash fungal disease

5. References

There are an estimated 8 billion ash trees – the majority being the white ash trees and the green ash trees.^[6][7][8][9]

Characteristics

The name white ash derives from the glaucous undersides of the leaves. It is similar in appearance to the green ash, making identification difficult. The lower sides of the leaves of white ash are lighter in color than their upper sides, and the outer surface of the twigs of white ash may be flaky or peeling. Green ash leaves are similar in color on upper and lower sides, and twigs are smoother. 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.^[10][11] Its compound leaves more often than not have 7 leaflets per leaf whereas other ash trees are usually more diverse.^[12]

Cultivation and uses

White ash is one of the most used trees for everyday purposes and, to keep up with high demand, is cultivated almost everywhere it can be. The wood is white and quite dense (within 20% of 670 kg/m³),^[14] strong, and straight-grained. Its species produces an ideal, Apical dominant Excurrent structured crown. And traditional timber of choice for production of baseball bats and tool handles. The wood is also favorable for furniture and flooring. Woodworkers use the timber mainly for interior uses due to high perishability in contact with ground soil.^[14] It is also used to make lobster traps. Since the 1950s, it has also become a popular choice for solid electric guitar bodies.^[15] It makes a very serviceable longbow if properly worked. The wood was used in ceiling fan blades from the 1970s through the mid-1980s, though cane was sometimes simulated with plastic then. It is no longer used for ceiling fan blades in most countries.

White ash is not seen in cultivation as often as green ash due to its preference for undisturbed forest sites away from urban pollution and soil compaction, but sometimes has been planted for its consistently reliably autumn colors, which typically are bright orange and red hues as opposed to other species of ash that produce a uniform yellow color.

Cultivation of White Ash differs across North American continent. For example, within City of Chicago region. 2010 Statistics show most common street tree species is White Ash at 6.2%. Along with third ranked Green type at 4.9%, Ashes combine to make up 11% percent of cities street trees. Along with overall population of 13,648,044 Million standing Ashes within Cook county alone. ^[16]

Autumn Purple, or Junginger. A wild Variety of American White Ash selected for its Purple leaf color. Had been discovered by University of Wisconsin Horticulturist Karl Junginger of McKay nursery, Waterloo, Iowa. And after its introduction in 1956, it quickly became the Most popular and most expensive landscape selection. Surpassing even the high priced Ginkgo, London Plane & White/Burr Oak. ^[17]

A related species, Biltmore ash, is sometimes treated as a variety of white ash. However, other taxonomists argue that Biltmore ash is its own species (Fraxinus biltmoreana).^[18][19]

North American native ash tree species are used by North American frogs as a critical food source, as the leaves that fall from the trees are particularly suitable for tadpoles to feed upon in ponds (both temporary and permanent), large puddles, and other water sources.^[20] Species such as red maple, which are taking the place of ash, due to the ash borer, are much less suitable for the frogs as a food source — resulting in poor frog survival rates and small frog sizes.^[20] It is the lack of tannins in the American ash variety that makes them good for the frogs as a food source and also not resistant to the ash borer. Varieties of ash from outside North America typically have much higher tannin levels and resist the borer. Maples and various non-native invasive trees, trees that are taking the place of American ash species in the North American ecosystem, typically have much higher leaf tannin levels.^[20] Ash species native to North America also provide important habit and food for various other creatures that are native to North America.^[21]

Emerald ash borer

The emerald ash borer (Agrilus planipennis), also commonly known by the acronym EAB, is a green beetle native to Asia.

In North America the emerald ash borer is an invasive species, highly destructive to ash trees in its introduced range. The damage of this insect rivals that of chestnut blight and Dutch elm disease.^[22] To put its damage in perspective, the number of chestnuts killed by the chestnut blight was around 3.5 billion chestnut trees while there are 3.5 billion ash trees in Ohio alone. Dutch elm disease killed only 200 million elm trees while EAB threatens 7.5 billion ash trees in the United States. The insect threatens the entire North American genus Fraxinus. Since its accidental introduction into the United States and Canada in the 1990s, and its subsequent detection in 2002, it has spread to eleven states and adjacent parts of Canada. It has killed at least 50 million ash trees so far and threatens to kill most of the ash trees throughout North America. The green ash and the black ash trees are affected. White ash is also killed rapidly, but usually only after green and black ash trees are eliminated. Blue ash displays some resistance to the emerald ash borer by forming callus tissue around EAB galleries; however, they are usually killed. Statistically, White ash has been less affected by emerald ash borer. Due to its smaller population within wild forests, where long term field studies in Michigan and Ohio have been underway. Similarly same for Black Ash, until studies undertaken within its primary natural range such as State of Minnesota. ^[23][24]

An infested tree can be recognized by premature fall color and leaf senescence observed on affected branches between August and last week of September. Before EAB officially identified, such dieback symptoms thought to have been caused by a vascular disease classified as Ash Yellows. Assuming damage caused by Borers taking advantage of weakened tree. Other recognizable signs regularly observed have been upper crown dieback, epicormic shoots or sprouts, bark lesions, frass filled larval galleries, ^[25]and deformed exit holes ; when the "Flatheaded" beetle has fully developed, it will bore out of the tree, in this instance, with a hole in a deformed "D" shape. In past it had been assumed, once any symptoms had started to show. Or "Once a tree had become Infested", it was likely too late to begin management. Today only on site professionals diagnosing an individual tree can responsibly make such determinations. ^[26]

Ash fungal disease

Hymenoscyphus fraxineus is a fungal disease that attacks ash trees. The disease causes leaf loss, crown dieback, and lesions in the bark. This fungus is, for the most part, fatal, both directly and indirectly, by weakening the tree's immune system so that it is more susceptible to attacks from pests or pathogens. Because of this fact, younger trees are affected far worse, and fully matured ash trees are capable of living long enough to reproduce.

The disease has spread over most of Europe and has been confirmed in Britain, however, it has not yet been found in North America.

The scale of the threat is not yet known, but is thought to be able to cause significant damage to the ash landscape of Europe and the UK.^[27]

References

• Vlaka, Bosnia and Herzegovina
• Vlaka (disambiguation)
• Vlakbult
• Vlakca
• Vlakfonteiu
• Vlakom prema jugu
• Vlakovo, Istria
• Vlak svobody
• Vlak u snijegu (film)
• Vlaky s rokmi
• Vlakča
• Vlambeer
• Vlamertinge
• Vlaming’s unicornfish
• VLAN tagging
• Vlantimir Stergiou
• Vlaovic
• Vlaović
• V. L. Arlazarov
• V.L. Arlazarov
• V'Las
• Vlasak
• Vlasakova
• Vlasanica (Vladimirci)
• Vlasaty, Minnesota