Historical clue formulations

• Symbol on an Oregon license plate — 2026-07-12
• Needle holder — 2026-06-14
• Tree alongside a ski run — 2026-05-21
• Tree whose wood is used for telephone poles — 2026-04-26
• Wood used for flooring — 2026-01-16
• Holiday centerpiece — 2025-11-11
• Certain evergreen — 2025-09-22
• Christmas centerpiece — 2025-05-30
• *"The mind is not a vessel to be filled but a ___ to be kindled": Plutarch — 2025-04-17
• Evergreen variety — 2025-01-19
• Many a Christmas tree — 2024-12-22
• Something trimmed after purchase — 2024-09-14
• It bears no etymological relation to "conifer," surprisingly — 2024-08-25
• Silver ___ (tree of the Alps) — 2024-03-05
• Douglas ___ — 2023-03-28
• Christmas tree — 2023-01-24
• Hemlock relative — 2022-01-09
• Cedar relative — 2021-09-15
• One is depicted on the Oregon license plate — 2021-07-03
• The "Tannen" of Tannenbaum — 2021-05-21
• Many a Christmas tree — 2020-06-23
• Tree that starts fires? — 2019-09-29
• Pre-Christmas purchase — 2019-05-09
• Balsam ___ (tree) — 2019-03-04
• Christmas tree — 2018-01-01
• Cone producer — 2017-05-04
• An evergreen — 2017-04-02
• An evergreen — 2017-02-13
• Growth along a ski run — 2016-12-01
• Common Yuletide purchase — 2016-07-27
• Needle holder — 2015-10-04
• Norwegian wood — 2015-06-03
• TREE — 2014-10-05
• Lighted tree, maybe — 2014-06-11
• Cone origin — 2014-02-06
• "O Tannenbaum" subject — 2013-12-05
• Christmas tree — 2013-08-19
• Tree with needles — 2013-03-11
• Christmas purchase — 2012-10-07
• Tree with needles — 2012-09-10
• Wreath source — 2012-08-19
• Gung-ho — 2012-06-14
• It's green year-round — 2012-04-10
• Douglas ___ — 2011-10-25
• Source of some paper pulp — 2011-09-22
• Provider of material for some wreaths — 2011-07-29
• Tree with cones — 2010-11-08
• Resinous tree — 2010-06-15
• Evergreen — 2010-03-01
• Tree-line tree — 2010-02-12