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Tree Campus: Flowering Ash/Manna Ash

Tree Campus SCC is a multi-year and interdisciplinary college initiative to document, map, and celebrate the incredible diversity of trees planted on the campus. With over 200 species, Shoreline Community College is an arboreal paradise that deserves to b


Flowering Ash/Manna Ash

Fraxinus ornus (OLEACEAE)



S. Europe, S.W. Asia



"Honey bees actively collect pollen on F. ornus and C. sativa, even nectar on the latter. A panicle of F. ornus provides higher number of flowers than a catkin of C. sativa, which may explain the variations in number of units visited on each plant. Also the difference in handling routines may reflect flower spatial arrangement: F. ornus, lacking a landing surface, is approached apparently in a disorganized way. Honey bees in fact invest in hectic movements that result in a pollen cloud, covering their body with pollen grains that are groomed later. This strategy may also be necessary to maximize the pollen release from F. ornus anthers, considering that (as exhaustively described by Pacini and Hesse, 2004) some plant species evolved mechanisms to allow gradual removal of the grains.

F. ornus and C. sativa constitute a perfect pollen source, even more important from an apicultural point of view. In fact, early pollen collection during the blooming season improves colonies survival and allows achieving stronger beehives. Moreover, since honey is a product very appreciated on the market, hive locations could be scheduled according to the flowering phenology of the closest wind pollinated species to increase colony productivity, honey production and the survival of local communities." [1]


Equity: Cultural and Historical Significance

"The bark is the part of the plant commonly used in the folk medicine for wound healing and treatment of inflammation, arthritis, and dysentery 2 . " [2]



"Compared to the other ashes, the timber quality is similar, although with a lower density. It is good quality, heavy, with narrow annual rings and a small difference between sapwood and heartwood. However, its timber wood is of low economic interest, as trees develop small and poorly-shaped trunks with many defects, so it is mainly used for small tool handles and household items. Managed manna ash forests usually are coppiced for producing firewood. In southern Mediterranean regions they are also managed by pollarding as a source of fodder for livestock (cattle, goats and sheep). Several ash varieties are used as ornamental trees in gardens and urban parks, appreciated for the abundance of white scented flowers and the autumnal foliage coloration. For this reason, this tree is also called flowering ash. Manna ash occurs principally on slopes, so it is an important component of protective forests and, thanks to its pioneer habit, it is also used for afforestation of degraded sites. Like the narrow-leaved ash, the damaged bark exudes a bitter-sweet tasting sap, which crystallises in the air into a yellow mass called manna. The main manna component is mannitol, a sugar alcohol, which has higher concentrations in trees planted in warmer regions. Manna was traditionally used in medicine as a laxative and digestive. During the last century manna was produced for extracting the mannitol, which is mainly used as a sweetener and for producing medicine. In southern Italy several ash plantations were established, until manna demand decreased as mannitol was first extracted by other sources (seaweeds, molasses) and then substituted by other synthesised products. Nowadays manna production is still active only in few rural areas of Sicily." [3]



[1] Giovanetti, M., & Aronne, G. (2011). Honey bee interest in flowers with anemophilous characteristics: first notes on handling time and routine on Fraxinus ornus and Castanea sativa. Bulletin of Insectology, 64(1), 77-82.

[2] Kostova, I. (2001). Fraxinus ornus L. Fitoterapia, 72(5), 471-480.

[3] Caudullo, G., & de Rigo, D. (2016). Fraxinus ornus in Europe: distribution, habitat, usage and threats. European Atlas of Forest Tree Species. San-Miguel-Ayanz, J. et al., Eds. Publication Office of the European Union, Luxembourg.

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