Would anyone know who holds the copyright to "We thank thee, Father, who hast planted" by F. Bland Tucker?
is where I would look first; it's also in Gather Comprehensive (ed.?); Hymnal 1940 info is likely to be out of date. My off-the-cuff guess would be, in the US, maybe Church Publishing?
"(c) 1941, Church Hymnal Corp." according to the copyright attribution in "Rejoice in the Lord". Its current name, according to http://www.churchpublishing.org , is "Church Publishing Incorporated (CPI)".