Sources:
http://www.maple-trees.com/pages/paperbark-maple.php
http://bhort.bh.cornell.edu/tree/themaples.htm
http://rubens.anu.edu.au/raid1/student_projects97/sumo/religion/shinto.html
https://dengarden.com/landscaping/japanese-maple-trees
http://www.european-trees.com/maple.html
https://www.absolutely-wild.com/images/uses-of-tree-sap-in-europe.pdf
http://www.missouribotanicalgarden.org/PlantFinder/PlantFinderDetails.aspx?taxonid=275374