Trees display red coloration in their leaves, bark, or stems, appearing either temporarily during autumn or persisting year-round. This red color can signal a tree’s annual preparation for dormancy or provide permanent visual interest, especially during winter. Understanding the biological reasons behind these displays helps distinguish between species known for seasonal color changes and those that maintain red features throughout the year.
The Chemistry of Red Coloration in Trees
The appearance of red in deciduous leaves begins when the tree halts chlorophyll production. Chlorophyll breakdown unmasks other pigments, such as the yellow and orange carotenoids, which are present throughout the growing season. The brilliant reds and purples, however, are caused by anthocyanins, a distinct group of pigments synthesized only when autumn begins.
Anthocyanins are newly synthesized in the leaf’s cell sap, forming when remaining sugars combine with compounds called anthocyanidins. These water-soluble pigments are stored in the plant cell vacuole and are responsible for the red and blue colors seen in many fruits and flowers. The specific hue is influenced by the acidity (pH) of the leaf tissue; more acidic conditions result in a brighter red color.
Environmental conditions influence the production of these pigments. The most vibrant red displays occur after warm, sunny days followed by cool, non-freezing nights. Sunny days allow the leaves to produce high levels of sugars needed for synthesis. Cool nights slow the sugar movement out of the leaf, causing a buildup that triggers red pigment production.
Trees Known for Seasonal Red Foliage
Many deciduous species shift dramatically to red foliage in the autumn, a display that lasts only a few weeks before the leaves drop. The Red Maple (Acer rubrum) is a recognized example, often turning brilliant scarlet, though some individuals may display orange or yellow. The leaves of all maples, including the Sugar Maple (Acer saccharum), are easily identified by their distinct, lobed shape.
Several oak species also contribute significantly to the red autumn landscape, notably the Northern Red Oak (Quercus rubra) and the Scarlet Oak (Quercus coccinea). Northern Red Oak leaves typically turn orangish-red to maroon, while Scarlet Oak produces an intense red color. Sumac (Rhus spp.) is a shrubby plant known for its brilliant crimson and scarlet foliage, thriving even in poor soils.
The Black Gum or Tupelo (Nyssa sylvatica) is known for its early and intense red display, often being one of the first trees to begin the color change in late summer. The leaves of the Flowering Dogwood (Cornus florida) provide a deep crimson color in the fall, following their attractive spring blossoms and summer fruit.
Trees with Permanent Red Features
Some trees exhibit red coloration as a persistent feature, most often in their bark or through specific cultivars bred for year-round foliage color. Certain varieties of Dogwood (Cornus), such as the Red-osier Dogwood, are valued for the bright, coral-red color of their young stems, which becomes most visible after the leaves drop in winter. The Paperbark Maple (Acer griseum) has bark that peels away in thin curls, exposing a rich, cinnamon-red inner layer that provides year-round texture and color.
Specific ornamental cultivars have been developed to maintain reddish-purple leaf color throughout the growing season. The Japanese Maple (Acer palmatum) has many such varieties, like ‘Bloodgood’ and ‘Atropurpureum.’ Their leaves emerge purple or deep wine-red in spring and hold that color until fall, when they may deepen to a crimson. The ‘Forest Pansy’ cultivar of the Eastern Redbud (Cercis canadensis) is prized for its heart-shaped leaves that remain a deep purple throughout the summer, contrasting with the species’ typical green.