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Why leaves turn red

Tech From Here: NL, beyond Dutch Design Week

The work this post covers and every source it draws on, each linked to the original.

Research cited

  1. Harvard Forest, "The Process of Leaf Color Change", Harvard University, undated (page footer ©2025) harvardforest.fas.harvard.edu
  2. 3):1296 to 1305, doi doi.org
  3. Hoch WA, Singsaas EL, McCown BH, "Resorption Protection. Anthocyanins Facilitate Nutrient Recovery in Autumn by Shielding Leaves from Potentially Damaging Light Levels" (excerpt) pmc.ncbi.nlm.nih.gov
  4. Harvard Forest, "Factors Influencing Autumn Leaf Color", Harvard University, undated harvardforest.fas.harvard.edu

Images, slide by slide

Slide 1
A tall tree in orange and red leaves above a row of brick houses and a wet pavement under a gray skyPhoto: RN Collins
Slide 2
Diagram of three leaves: green in summer, yellow when chlorophyll breaks down, red when new anthocyanins are madeImage: RN Collins studio, code-drawn. Checked against Harvard Forest, The Process of Leaf Color Change, : "All leaves gradually lose chlorophyll during the growing season, and this loss accelerates before leaf fall." Carotenoids: "some of them are retained in the plastids after the chlorophyll is removed." Red: "the active synthesis of anthocyanin pigments just before the leaves fall from the trees."Museum or journal record
Slide 3
A broad tree with green and yellowing leaves and a few red ones, brick houses behind itPhoto: RN Collins
Slide 4
The crown of a tree in orange, red and some green leaves against a pale gray skyPhoto: RN Collins
Slide 5
A quiet brick street with terraced houses, a small tree with reddish leaves in the middle distance, fallen leaves on the kerbPhoto: RN Collins
Ring frame
Scallop-shaped covered bowl with a leaf-shaped stand, c. 1775 to c. 1799, Rijksmuseum (AK-NM-6432)Frame: Rijksmuseum, PD, cropped

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