Short answers, pulled from the story.
Fraxinus, commonly called ash, is a genus of 45 to 65 species of usually medium-to-large trees in the olive family, Oleaceae. Most species are deciduous, though some subtropical species are evergreen. The genus is widespread across much of Europe, Asia, and North America.
Both the Old English word aesc and the Latin fraxinus carried a secondary meaning of spear because ash wood was the standard material for spear shafts in pre-industrial Europe. The dual meaning is preserved in both words and traces back to Proto-Indo-European roots.
The emerald ash borer, Agrilus planipennis, accidentally introduced from eastern Asia in the late 1980s to early 1990s via solid wood packing material, has killed tens of millions of ash trees across 22 US states and the Canadian provinces of Ontario and Quebec. An estimated seven billion ash trees in North America remain threatened.
Ash dieback, caused by the fungus Hymenoscyphus fraxineus, has been spreading through European ash trees since the mid-1990s. The disease has infected about 90 percent of Denmark's ash trees, and was confirmed in mature woodland in the UK in 2012.
In Norse mythology, the vast ash tree Yggdrasil serves as the axis mundi sustaining the nine worlds of the cosmos, and Askr, the name of the first man, literally means ash. In Greek mythology, the Meliae, nymphs of the ash tree, were born from drops of Ouranos's blood falling on the earth according to Hesiod's Theogony.
Ash wood is used for tool handles, electric guitar bodies, and drum shells; Fender has used ash as a tonewood for electric guitars since 1950. The Morgan Motor Company of Great Britain manufactures sports car frames from ash. Additional uses include furniture, agricultural tools, firewood, and household objects such as bowls and spoons.