spruceyoudaoicibaDictYouDict[spruce 词源字典]
spruce: Spruce ‘neat’ [16] and spruce the tree [17] are completely different words, of course, but they could have a common origin – in Spruce, the old English name for Prussia. Spruce the tree was originally the spruce fir, literally the ‘Prussian fir’. And it is thought that the adjective spruce may have come from the expression spruce leather ‘Prussian leather’, which denoted a particularly fine sort of leather, used for making jackets. The word itself is an unexplained alteration of Pruce ‘Prussia’, which was acquired via Old French from medieval Latin Prussia.
=> prussia[spruce etymology, spruce origin, 英语词源]
spruce (n.)youdaoicibaDictYouDict
1660s, "evergreen tree, fir," from spruse (adj.) "made of spruce wood" (early 15c.), literally "from Prussia," from Spruce, Sprws (late 14c.), unexplained alterations of Pruce "Prussia," from an Old French form of Prussia.

Spruce seems to have been a generic term for commodities brought to England by Hanseatic merchants (especially beer, boards and wooden chests, and leather), and the tree thus was believed to be particular to Prussia, which for a time was figurative in England as a land of luxuries. Compare spruce (adj.).

As a distinct species of evergreen tree from 1731. Nearly all pines have long, soft needles growing in groups of two (Scotch) to five (white); spruce and fir needles grow singly. Spruce needles are squarish and sharp; fir needles are short and flat. Cones of the fir stand upright; cones of a spruce hang before falling.
spruce (v.)youdaoicibaDictYouDict
"to make trim or neat," 1590s, from spruce (adj.). Related: Spruced; sprucing.
spruce (adj.)youdaoicibaDictYouDict
"neat, smart in dress and appearance, dapper, brisk," 1580s, from spruce leather (mid-15c.; see spruce (n.)), a type of leather imported from Prussia in the 1400s and 1500s which was used in England to make a popular style of jerkin that was considered smart-looking.