Spruce
late Middle English (denoting Prussia or something originating in Prussia): alteration of obsolete Pruce ‘Prussia’. The application to the tree dates from the early 17th century.
wiktionary
From Middle English Spruce, an alteration of Pruce(“Prussia”), from Medieval Latin, from a Baltic language, probably Old Prussian; for more, see Prussia. Spruce, spruse (1412), and Sprws (1378) were terms for commodities brought to England by Hanseatic merchants (beer, wood, leather). The tree with this name was also believed to have been native to Prussia. The adjective and verb senses ("trim, neat" and "to make trim, neat") are attested from 1594, and originate with spruce leather (1466), which was used to make a popular style of jerkins in the 1400s that was considered smart-looking.
etymonline
spruce (n.)
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.)
"to make trim or neat," 1590s, from spruce (adj.). Related: Spruced; sprucing.
spruce (adj.)
"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.
